CHAPTER 3

SOURCES OF INTERNATIONAL LAW

3.1Introduction

The term ‘sources of law’ has generated considerable debate among writers and is capable of conveying more than one meaning.

In English jurisprudence at least, the classic scheme of the sources of law is that of Salmond, who divided them first into those which are ‘formal’ and those which are ‘material’ – those imparting to a given rule the force of law and those from which its substance is drawn. He further subdivided ‘material sources’ into ‘legal’ and ‘historical’ sources – those which the law itself acknowledges, such as statute and judicial precedent in England, and those which, though possibly no less influential, are not so acknowledged, as, for instance, the Roman legal system from which, via judicial precedent, many English rules are derived. Finally, in a footnote, Salmond distinguished a category of ‘literary’ sources, consisting in ‘the sources of our knowledge of the law, or rather the original authoritative sources of our knowledge, as opposed to later commentary and literature’.1

Though its primary distinction between ‘formal’ and ‘material’ sources, however difficult of application in practice, still commands some general acceptance, Salmond’s scheme has been much criticised. The alternatives to it which have been proffered have not, however, fared much better. Indeed Sir Carleton Allen, Salmond’s chief critic, is regarded by Professor Paton as advocating the abandonment of the search for the sources of law in favour of an enquiry, into first, its validity and, second, the origins of the materials from which it is fashioned, on the ground that the multiplicity of theories has utterly confused the term ‘source’.2

The traditional notion of sources in international law: terminology

International lawyers appear to have persisted longer in the search for ‘sources’. Whether this is because they have displayed a greater capacity for the clear definition of terms is perhaps questionable. But their terminology is, in any case, slightly different from Salmond’s.

In an endeavour to introduce some order into the words used, Professor Corbett essayed 40 years ago to distinguish different elements relevant to the discussion. He laid it down thus:

1The cause of international law is the desire of states to have the mutual relations which their social nature renders indispensable regulated with the greatest possible rationality and uniformity.

2The basis of the rules of international law as a system and of the rules of which it is composed is the consent of states.

3The origins of the rules of international law, which may also be called ‘the sources’ of that law – though the word ‘source’ has such a history of confusion behind it that it might well be abandoned – are the opinions, decisions or acts constituting the starting point from which their more or less gradual establishment can be traced.

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1Salmond, Jurisprudence, 10th edn, 1947, London: Sweet & Maxwell at pp 151–56.

2Paton, Jurisprudence, 3rd edn, 1964, Oxford: Clarendon Press at pp 159–60.

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4The records or evidence of international law are the documents or acts proving the consent of states to its rules. Among such records or evidence, treaties and practice play an essential part, though recourse must be had to unilateral declarations, instructions to diplomatic agents, laws and ordinances, and, in a

lesser degree, to the writings of authoritative jurists. Custom is merely that general practice which affords conclusive proof of a rule.3

Amongst the interesting features of this series of propositions is, first, that the term but not ostensibly the concept of ‘sources’ of law is condemned, though both term and concept are narrower than Salmond would have made them; and, secondly, the introduction of the term ‘evidence’. This last is something more, it is clear, than Salmond’s ‘literary sources’.

Even writers in English have not adhered to these golden rules, as is testified by John Basset Moore, who usually had a pretty turn of phrase. For, in the Introduction to his great series of International Adjudications he wrote:

Being desirous to deal with the substance of things, and, by avoiding as far as possible wars of epithets, to save a great cause from needless injury and attrition, I have placed the words ‘source’ and ‘evidence’ [in the title to a section on the influence of arbitral decisions on the law] in the alternative, thus leaving it to their partisans, who may often agree except in terminology, the unchallenged enjoyment of the title they prefer.4

Oppenheim endeavoured to resolve the confusion between ‘source’ and ‘cause’ by tracing the former term to its own source, in the meaning of spring or well, which:

... has to be defined as the rising from the ground of a spring of water. When we see a stream of water and want to know whence it comes, we follow the stream upwards until we come to the spot where it rises naturally from the ground. On that spot, we say, is the source of the stream of water. We know very well that this source is not the cause of the existence of the stream of water ...5

...

If we apply the conception of source in this meaning to the term ‘source of law’ the confusion of source with cause cannot arise. Just as we see streams of water running over the surface of the earth, so we see, as it were, streams of rules running over the area of law. And if we want to know whence these rules come, we have to follow these streams upwards until we come to the beginning; where we find that such rules do not rise from a spot on the ground as water does; they rise from facts in the historical development of a community. Thus in Great Britain a good many rules rise each year from Acts of Parliament. ‘Source of law’ is therefore the name for an historical fact out of which rules of conduct rise into existence and legal force.6

Romantic and evocative though I find this image, I must avow that it is unhelpful to me for at least two reasons. First, I feel that the assertion that an Act of Parliament is, or is simply, ‘an historical fact’ would stand, and would not

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3Corbett, ‘The Consent of States and the Sources of the Law of Nations’ (1925) BYIL VI at pp 20, 29–30.

4International Adjudications, Modern Series (1929), Vol I, p xii.

5Oppenheim, International Law, Vol I, 8th edn, 1955, London: Longman at p 24.

6Oppenheim, International Law, Vol I, 8th edn, 1955, ibid at p 25.

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withstand, closer examination. And secondly, though I can see that an Act of Parliament would be both a ‘literary source’ in Salmond’s sense and an item of ‘evidence’ in Professor Corbett’s, and that this circumstance would not exclude its inclusion in other categories established by those authors (since these categories are not necessarily on the same plane or not mutually exclusive), I am troubled by the possible effect of Professor Corbett’s cursory assignment of custom to the category of evidence.

To say this is perhaps to be obscure unless it is first explained that Oppenheim goes on almost immediately to say that ‘Custom is the oldest and original source of international law’, to define it as ‘a clear and continuous habit of doing certain actions [which] has grown up under the aegis of a conviction that these actions are, according to international law, obligatory or right’, and to distinguish it from mere usage, a habit which has grown up without any such conviction.7 Professor Corbett is no doubt more logical here: he says, in effect, custom merely proves or illustrates – or indeed merely provides evidence – that the conduct it reflects is obligatory. Therefore, in his system it cannot be a ‘source’ – an origin. Oppenheim says or implies in somewhat circular fashion that a custom is already considered as binding before it becomes such, but it is for him a source. But perhaps I misunderstand Professor Corbett here. Perhaps what he terms practice is Oppenheim’s custom, and presumably he would concede practice to be both source and evidence in his sense. The alternative, which is not to be excluded, is that Professor Corbett has in fact carried out his threat and excised ‘source’ in all but name from his system: certainly it is difficult to regard practice, however, defined, as involving no more than ‘the opinions, decisions or acts constituting the starting-point’.

However, this may be, it is well – a point sometimes overlooked by students of international law – to see briefly how writers in other languages and other countries regard the matter of terminology. A fair and accurate summary seems, if one may say so, to be provided by Professor Sorensen, who says that in usual legal language the sources of international law are those things which indicate the actual or concrete content of that system. Admittedly, certain authors prefer to avoid the term altogether or substitute alternative lines of enquiry for an enquiry after sources. Among these he includes Professor Corbett, thus confirming in some measure the suspicion we have already aired. But there is no harm in retaining the word if one makes sure how it is intended to be used. And it should not be used in relation to the question why international law is in general binding: that is the problem of ‘basis’, upon which designation Professor Corbett and many others agree,8 or of ‘source’ in the singular. Nor should it be used in connection with the question what are the ‘material sources’ of international law in the sense of the elements and influences determining its content, be they the practical interests and needs of states or the idealistic urgings of the social conscience or the ideologies prevailing at any particular time.9 10

Clive Parry makes reference to Oppenheim’s International Law and cites passages from the eighth edition which was published in 1955. The view

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7Oppenheim, International Law, Vol I, 8th edn, 1955, ibid at pp 25–26.

8Cf Brierly, The Basis of Obligation in International Law, 1958, Oxford: Clarendon Press.

9Sorensen, Les Sources du Droit International, 1946, Copenhagen: E Munksgaard.

10Clive Parry, The Sources and Evidences of International Law, 1965, Manchester: Manchester University Press at pp 1–5.

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taken by the editors of the ninth edition (published in 1992) is slightly different:

There is much discussion of the meaning to be attributed to such terms as ‘source’, ‘cause’, ‘basis’ and ‘evidence’ of international law.11 There is, however, an unavoidable degree of flexibility and overlap in the use of such terms, and little practical purpose is served in attempting to define them too precisely or to differentiate them too rigidly. Nevertheless, the concept of a ‘source’ of a rule of law is important, since it enables rules of law to be identified and distinguished from other rules (in particular rules de lege ferenda) and concerns the way in which the legal force of new rules of conduct is established and in which existing rules are changed.

The causes of a rule of law are generally to be found in particular social and historical circumstances in the development of a community, which suggest the need for a rule of conduct in a particular sense. The source of a rule of law is, by contrast, to be found in the process by which it first becomes identifiable as a rule of conduct with legal force and from which it derives its legal validity.

The sources of international law must not be confused with the basis of international law; this, as we have seen, is to be found in the common consent of the international community. The sources of law, on the other hand, concern the particular rules which constitute the system, and the processes by which the rules become identifiable as rules of law. The sources of the rules of law, while therefore distinct from the basis of the law, are nevertheless necessarily related to the basis of the legal system as a whole.

We should at this point also note the distinction between the formal and the material sources of international law. The former – with which we are more concerned here – is the source from which the legal rule derives its legal validity, while the latter denotes the provenance of the substantive content of that rule. Thus, for example, the formal source of a particular rule may be custom, although its material source may be found in a bilateral treaty concluded many years previously, or in some state’s unilateral declaration.12

The attempt is often made to distinguish between the basis, the causes, the sources, the formal and material sources, and the evidence of sources of international law. These and similar distinctions may be useful, within limits, so long as their importance is not exaggerated and so long as they are not permitted to conceal the essential identity of the subject matter which they are intended to elucidate. The basis – the primary cause – of international law is the fact of the existence of an international society composed of human beings organised as sovereign states. Its more immediate cause (or, as it is occasionally referred to, its objective source) is the interdependence, in its manifold manifestations, of these sovereign states; the need to safeguard their interests and their independent existence by means of binding rules of law; and the necessity to protect the individual human being who is the ultimate unit of all law, in so far as such protection, both of nationals and aliens, is rendered relevant by reference to the existence of separate sovereign states ...

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11On the different meanings of these terms see Corbett (1925) BYIL 6 at pp 20–30; Fitzmaurice in Symbolae Verzijl, 1958, p 153; Parry, The Sources and Evidences of International Law, 1965, Manchester: Manchester University Press .

12Jennings and Watts (eds), Oppenheim’s International Law, 9th edn, 1992, London: Longman at p 23.

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The more direct sources of international law are the agencies, human or other, by means of which it is expressed and rendered binding.13

Some writers have gone further to argue that the whole idea of ‘sources’ of international law is flawed. For example, O’Connell has written:

Sometimes the word ‘source’ is used to indicate the basis of international law; sometimes it is confused with the social origin and other ‘causes’ of the law; at others it is indicative of the formal law-making agency and at others again it is used instead of the term evidence of the law... As a figurative association the word ‘source’ is misleading and should be discarded.14

3.2Article 38 of the Statute of the International Court of Justice

1The Court, whose function is to decide in accordance with international law such disputes as are submitted to it, shall apply:

(a)international conventions, whether general or particular, establishing rules expressly recognised by the contesting states;

(b)international custom, as evidence of a general practice accepted as law;

(c)the general principles of law recognised by civilised nations;

(d)subject to the provisions of Article 59, judicial decisions and the teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law.

2This provision shall not prejudice the power of the Court to decide a case ex aequo et bono, if the parties agree thereto.15

The traditional starting point for any discussion of the sources of international law has been Article 38 of the Statute of the International Court of Justice. Apart from a few formal changes the Statute is similar to the Statute of the Permanent Court of International Justice. The Permanent Court of International Justice (PCIJ) was created in 1920 under the auspices of the League of Nations and the Statute was drafted by an ‘Advisory Committee of Jurists’ appointed by the Council of the League of Nations. The role and procedures of the International Court are discussed in Chapter 12.

The search for the thing which, by the highest compulsive force as it were, gives to the content of the rules of international law their character as law, whither should it be directed? The traditional approach leads one to turn to Article 38(1) of the Statute of the International Court of Justice – formerly the same article in the Statute of the Permanent Court of International Justice. Quite why this should be the approach is not wholly clear. That article, says Brierly, is ‘a text of the highest authority’,16 which is to state the proposition to be proved. The article does not even say that it purports to be a list of sources otherwise than by implication. For it simply states that the Court ‘whose function it is to decide in accordance with international law such disputes as are submitted to it, shall

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13E Lauterpacht (ed), International Law – Collected Papers of Hersch Lauterpacht, Vol 1, 1970, Cambridge: Cambridge University Press at p 51.

14O’Connell, International Law, Vol 1, 1970, London: Stevens.

15Article 38 of the Statute of the International Court of Justice.

16Brierly, Law of Nations, 6th edn, 1963, Oxford: Clarendon Press at p 56.

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apply’ that which it prescribes. One of the matters so prescribed is ‘the writings of the most highly qualified publicists ... as a subsidiary means for the determination of rules of law’, a formulation which suggests less a formal source than what Salmond would have called no more than legal literature – not even a literary source. Another item echoes, or is echoed by, Professor Corbett: namely ‘international custom as evidence of a general practice accepted by law’ – not a source at all according to him, if he admits any sources at all.17

Article 38 does not actually use the term ‘sources’ but rather describes how the Court is to decide disputes which come before it for settlement. Law is not necessarily simply defined in terms of how courts decide disputes. Article 38 does not refer to resolutions of the United Nations or other international organisations yet such resolutions may play an extremely important role in international society and may arguably constitute a source of law. A question that will be considered at the end of this chapter is the extent to which Article 38 is to be regarded as a comprehensive list of the sources of international law.

Another question that arises is whether Article 38 para 1 creates a hierarchy of sources. It is argued that there is no rigid hierarchy, but those drafting the article intended to give an order and in practice the Court may be expected to observe the order in which they appear. (a) and (b) are obviously the important sources, and the priority of (a) is explicable by the fact that this refers to a source of mutual obligation of the parties – source (a) is thus not primarily a source of rules of general application, although as we shall see, treaties may provide evidence of the formation of custom. It may be useful here to note what Lauterpacht has written on the issue:

The order in which the sources of international law are enumerated in the statute

... is, essentially, in accordance both with correct legal principle and with the character of international law as a body of rules based on consent to a degree higher than is law within the state. The rights and duties of states are determined, in the first instance, by their agreement as expressed in treaties – just as, in the case of individuals, their rights are specifically determined by any contract which is binding upon them. When a controversy arises between two or more states with regard to a matter regulated by treaty, it is natural that the parties should invoke and that the adjudicating party should apply, in the first instance, the provisions of the treaty in question.18

3.3Treaties

Treaties represent a source of law whose importance has grown since 1945. In this chapter we are only concerned with treaties as a source of law. Chapter 4 deals with the mechanics of treaty making and enforcement in more detail. Treaties may be bipartite/bilateral or multipartite/multilateral and they may create particular or general rules of international law. A distinction is often drawn between law-making treaties (traité-lois) and treaty contracts (traité contracts). The essence of the distinction lies in the fact that treaty contracts,

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17Clive Parry, The Sources and Evidences of International Law, 1965, Manchester: Manchester University Press at p 5.

18Lauterpacht, International Law, Collected Papers, Vol 1, p 87.

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being agreements between relatively few states, can only create a particular obligation between the signatories, an obligation which is capable of fulfilment, eg an agreement between France, Germany and the UK to develop and build a new fighter jet. Law-making treaties create obligations which can continue as law, eg an agreement between 90 states to outlaw the use of torture. There has been a great increase in the number of law-making treaties throughout this century. One reason for this growth is the increase in the number of states and the fact that many new states have a lack of faith in any rules of customary international law in which they have not played a part in creating. The term ‘law-making’ can lead to confusion and it should be used with care – strictly speaking no treaty can bind non-signatories. Even a multipartite treaty only binds those states which are party to it. The mere fact that a large number of states are party to a multilateral convention does not make it binding on nonparties although its existence may be evidence of customary international law as was discussed in the North Sea Continental Shelf cases (1969).19 For this reason sometimes the term law-making is replaced by ‘normative’. Normative treaties bind signatories as treaties, but may also provide evidence of rules of custom which bind all states. Examples of normative treaties would include treaties operating a general standard setting instrument – eg International Covenant on Civil and Political Rights 1966; and treaties creating an internationally recognised regime – eg the Antarctic Treaty 1959.

Customary law and treaty law have equal authority. However if there is a conflict between the two it is the treaty that prevails. This point is illustrated by the Wimbledon case (1923).20 In that case the PCIJ, while recognising that customary international law prohibited the passage of armaments through the territory of a neutral state into the territory of a belligerent state, upheld the Treaty of Versailles Article 380, which provided that the Kiel canal was to be free and open to all commercial vessels and warships belonging to states at peace with Germany. In stopping a vessel of a state with which it was at peace, Germany was in breach of treaty obligations. It should, however, be noted that there is a presumption against the replacement of custom by treaty – treaties will be construed to avoid conflict with rules of custom unless the treaty is clearly intended to overrule existing custom.

3.4Custom

In any society rules of acceptable behaviour develop at an early stage and the international community is no exception. As contact between states increased, certain norms of behaviour crystallised into rules of customary international law. Until comparatively recently the rules of general international law were nearly all customary rules.

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19Federal Republic of Germany v Denmark; Federal Republic of Germany v The Netherlands [1969] ICJ Rep 3.

20PCIJ Rep, Ser A, No 1.

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3.4.1 Definitions of international custom

Custom in international law is a practice followed by those involved because they feel legally obliged to behave in such a way. Custom must be distinguished from mere usage, such as acts done out of courtesy, friendship or convenience rather than out of obligation or a feeling that non-compliance would produce legal consequences. Article 38 circumscribes customary law as ‘international custom, as evidence of a general practice accepted as law.’ The Court cannot apply custom, only customary law and subpara 1(b) arguably reverses the logical order of events since it is general practice, accepted as law, which constitutes evidence of a customary rule. Judge Hudson of the International Law Commission listed the following criteria for the establishment of a customary rule:

(a)concordant practice by a number of states with reference to a type of situation falling within the domain of international relations;

(b)continuation or repetition of the practice over a considerable period of time;

(c)conception that the practice is required by, or consistent with, prevailing international law; and

(d)general acquiescence in the practice by other states.21

How then is custom distinguished from behaviour which involves no legal obligation? The traditional view is that a rule of customary international law derives its validity from the possession of two elements: a material element and a psychological element. The material element refers to the behaviour and practice of states; whereas the psychological element, usually referred to as the opinio juris sive necessitatis or simply opinio juris, is the subjective conviction held by states that the behaviour in question is compulsory and not discretionary. Any alleged rule of customary law must therefore be checked as to its material and its psychological element.

ASYLUM CASE22

The Colombian government has finally invoked ‘American international law in general’. In addition to the rules arising from agreements which have already been considered, it has relied on an alleged regional or local custom peculiar to Latin-American states.

The Party which relies on a custom of this kind must prove that this custom is established in such a manner that it has become binding on the other Party. The Colombian government must prove that the rule invoked by it is in accordance with a constant and uniform usage practised by the states in questions, and that this usage is the expression of a right appertaining to the state granting asylum and a duty incumbent on the territorial state. This follows from Article 38 of the Statute of the Court, which refers to international custom ‘as evidence of a general practice accepted as law’.

In support of its contention concerning the existence of such a custom, the Colombian government has referred to a large number of ... treaties ...

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21UN Doc A/CN4/16 3/3/50 at p 5.

22Asylum case (Columbia v Peru) [1950] ICJ Rep 266.

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Finally, the Colombian government has referred to a large number of particular cases in which diplomatic asylum was in fact granted and respected. But it has not shown that the alleged rule ... was invoked or – if in some cases it was in fact invoked – that it was, apart from conventional stipulations, exercised by the states granting asylum as a right appertaining to them and respected by territorial states as a duty incumbent on them and not merely for reasons of political expediency. The facts brought to the knowledge of the Court disclose so much uncertainty and contradiction, so much fluctuation and discrepancy in the exercise of diplomatic asylum and in the official views expressed on various occasions, there has been so much inconsistency in the rapid succession of conventions on asylum, ratified by some states and rejected by others, and the practice has been so much influenced by considerations of political expediency in the various cases, that it is not possible to discern in all this any constant and uniform usage, accepted as law, with regard to the alleged rule of unilateral and definitive qualification of the offence.

The Court cannot therefore find that the Colombian government has proved the existence of such a custom. But even if it could be supposed that such a custom existed between certain Latin-American states only, it could not be invoked against Peru which, far from having by its attitude adhered to, has, on the contrary, repudiated it by refraining from ratifying the Montevideo Conventions of 1933 and 1939, which were the first to include a rule concerning the qualification of the offence in matters of diplomatic asylum.

NORTH SEA CONTINENTAL SHELF CASES23

70The Court must now proceed to the last stage in the argument put forward on behalf of Denmark and the Netherlands. This is due to the effect that even if there was at the date of the Geneva Convention no rule of customary international law in favour of the equidistance principle, and no such rule was crystallised in Article 6 of the Convention, nevertheless such a rule has come into being since the Convention, partly because of its own impact, partly on the basis of subsequent state practice – and that this rule, being now a rule of customary international law binding on all states, including therefore the Federal Republic, should be declared applicable to the delimitation of the boundaries between the Parties’ respective continental shelf areas in the North Sea.

71In so far as this contention is based on the view that Article 6 of the Convention has had the influence, and has produced the effect described, it clearly involves treating that Article as a norm-creating provision which has constituted the foundation of, or has generated a rule which, while only conventional or contractual in its origin, has since passed into the general corpus of international law, and is now accepted as such by the opinio juris, so as to have become binding even for countries which have never, and do not, become parties to the Convention. There is no doubt that this process is a perfectly possible one and does from time to time occur: it constitutes indeed one of the recognised methods by which new rules of customary international law may be formed. At the same time this result is not lightly to be regarded as having been attained.

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23Federal Republic of Germany v Denmark; Federal Republic of Germany v The Netherlands [1969] ICJ Rep 3.

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72It would in the first place be necessary that the provision concerned should, at all events potentially, be of a fundamentally norm-creating character such as could be regarded as forming the basis of a general rule of law. Considered in abstracto the equidistance principle might be said to fulfil this requirement. yet in the particular form in which it is embodied in Article 6 of the Geneva Convention, and having regard to the relationship of that Article to other provisions of the Convention, this must be open to some doubt. In the first place, Article 6 is so framed as to put second the obligation to make use of the equidistance method, causing it to come after a primary obligation to effect delimitation by agreement. Such a primary obligation constitutes an unusual preface to what is claimed to be a potential general rule of law. Without attempting to enter into, still less pronounce upon on question of jus cogens, it is well understood that, in practice, rules of international law can, by agreement, be derogated from in particular cases, or as between particular parties – but this is not normally the subject of any express provision, as it is in Article 6 of the Geneva Convention. Secondly, the part played by the notion of special circumstances relative to the principle of equidistance as embodied in Article 6, and the very considerable, still unresolved controversies as to the exact meaning and scope of this notion. must raise further doubts as to the potentially norm-creating character of the rule. Finally, the faculty of making reservations to Article 6, while it might not of itself prevent the equidistance principle being eventually received as general law, does add considerably to the difficulty of regarding this result as having been brought about (or being potentially possible) on the basis of the Convention: for so long as this faculty continues to exist, and is not made the subject of any revision brought about in consequence of a request made under Article 13 of the Convention – of which there is at present no official indication – it is the Convention itself which would, for the reasons already indicated, seem to deny to the provisions of Article 6 the same norm-creating character as, for instance, Articles 1 and 2 possess.

73With respect to the other elements usually regarded as necessary before a conventional rule can be considered to have become a general rule of international law, it might be that, even without the passage of any considerable period of time, a very widespread and representative participation in the convention might suffice of itself, provided it included that of states whose interests were specially affected. In the present case, however, the Court notes that, even if allowance is made for the existence of a number of states to whom participation in the Geneva Convention is not open, or which, by reason for instance of being land-locked states, would have no interest in becoming parties to it, the number of ratifications and accessions so far secured is, though respectable, hardly sufficient. That nonratification may sometimes be due to factors other than active disapproval of the convention concerned can hardly constitute a basis on which positive acceptance of its principles can be implied. The reasons are speculative, but the facts remain.

74As regards the time element, the Court notes that it is now over ten years since the Convention was signed, but that it is even now less than five years since it came into force in June 1964, and that when the present proceedings were brought it was less than three years, while less than one had elapsed at the time when the respective negotiations between the Federal Republic and the other two Parties for a complete delimitation broke down on the question of the application of the equidistance principle . Although the passage of only a short period of time is not necessarily, or of itself, a bar to the formation of a

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new rule of customary international law on the basis of what was originally a purely conventional rule, an indispensable requirement would be that within the period in question, short though it might be, state practice, including that of states whose interests are specially affected, should have been both extensive and virtually uniform in the sense of the provision invoked – and should moreover have occurred in such a way as to show a general recognition that a rule of law or legal obligation is involved.

75The Court must now consider whether state practice in the matter of continental shelf delimitation has, subsequent to the Geneva Convention, been of such a kind as to satisfy this requirement ... Some fifteen cases have been cited in the course of the present proceedings, occurring mostly since the signature of the 1958 Geneva Convention, in which continental shelf boundaries have been delimited according to the equidistance principle – in the majority of the cases by agreement, in a few other, unilaterally – or else the delimitation was foreshadowed but has not yet been carried out ... even if these various cases constituted more than a very small proportion of those potentially calling for delimitation in the world as a whole, the Court would not think it necessary to enumerate or evaluate them separately, since there are, a priori, several grounds which deprive them of weight as precedents in the present context.

76... Over half the states concerned, whether acting unilaterally or conjointly, were or shortly became parties to the Geneva Convention, and were therefore presumably, so far as they were concerned, acting actually or potentially in the application of the Convention. From their action no inference could legitimately be drawn as to the existence of a rule of customary international law in favour of the equidistance principle. As regards those states, on the other hand, which were not, and have not become parties to the Convention, the basis of their action can only be problematical and must remain entirely speculative. Clearly, they were not applying the Convention. But from that no inference could justifiably be drawn that they believed themselves to be applying a mandatory rule of customary international law. There is not a shred of evidence that they did and ... there is no lack of other reasons for using the equidistance method, so that acting, or agreeing to act in a certain way, does not of itself demonstrate anything of a juridical nature.

77The essential point in this connection – and it seems necessary to stress it – is that even if these instances of action by non-parties to the Convention were much more numerous than they in fact are, they would not, even in the aggregate, suffice in themselves to constitute the opinio juris – for, in order to achieve this result, two conditions must be fulfilled. Not only must the acts concerned amount to a settled practice, but they must also be such, or be carried out in such a way, as to be evidence of a belief that this practice is rendered obligatory by the existence of a rule requiring it. The need for such a belief, ie the existence of a subjective element, is implicit in the very notion of the opinio juris sive necessitatis. The states concerned must therefore feel that they are conforming to what amounts to a legal obligation. The frequency, or even habitual character of the acts is not in itself enough. There are many international acts, eg in the field of ceremonial and protocol, which are performed almost invariably, but which are motivated only by considerations of courtesy, convenience or tradition, and not by any sense of legal duty.

78In this respect the Court follows the view adopted by the Permanent Court of Justice in the Lotus Case, as stated in the following passage, the principle of which is, by analogy, applicable almost word for word, mutatis mutandis, to the present case (PCIJ Ser A, No 10, p 28, (1927)):

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Even if the rarity of the judicial decisions to be found ... were sufficient to prove ... the circumstances alleged ... it would merely show that states had often, in practice, abstained from instituting criminal proceedings, and not that they recognised themselves as being obliged to do so; for only if such abstention were based on their being conscious of having a duty to abstain would it be possible to speak of an international custom. The alleged fact does not allow one to infer that states have been conscious of having such a duty; on the other hand ... there are other circumstances calculated to show that the contrary is true.

Applying this dictum to the present case, the position is simply that in certain cases – not a great number – the states concerned agreed to draw or did draw the boundaries concerned according to the principle of equidistance. There is no evidence that they so acted because they felt legally compelled to draw them in this way by reason of a rule of customary law obliging them to do so

– especially considering that they might have been motivated by other obvious factors ...

81The Court accordingly concludes that if the Geneva Convention was not in its origins or inception declaratory of a mandatory rule of customary international law enjoining the use of the equidistance principle for the delimitation of continental shelf areas between adjacent states; neither has its subsequent effect been constitutive of such a rule; and that state practice up- to-date has equally been insufficient for this purpose ...

It should be noted that in recent years a number of writers have criticised this traditional view of customary law. In an article written in 1982, Sir Robert Jennings, former President of the ICJ criticised the traditional view on the basis that it was outworn and inadequate and commented:

... most of what we perversely persist in calling customary international law is not only not customary law, it does not even faintly resemble a customary law.24

Critics of the traditional view argue that although the ICJ speaks in terms of state practice and opinio juris, increasingly its conclusions are determined by the application of legal rules that are largely treated as self-evident. The interpretation of state practice and opinio juris is never a straightforward automatic operation but involves a choice, usually justified on grounds of relevance, between conflicting facts and statements. Advocates of the nontraditional view, such as Martti Koskenniemi and Bruno Simma, argue that the study of international law must involve discussion of the way in which that choice is to be made. There is considerable merit to this view and an attempt will be made here to look critically at the way in which the ICJ deals with alleged rules of international custom.

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24‘The Identification of International Law’ in Cheng, International Law: Teaching and Practice, 1982, London: Stevens.

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3.4.2 The material element

3.4.2.1 State practice

State practice includes any act, articulation, or other behaviour of a state which discloses the state’s conscious attitude concerning a customary rule or its recognition of a customary rule. In 1950 the International Law Commission listed the following classical forms of ‘Evidence of Customary International Law’:

•treaties;

•decisions of national and international courts;

•national legislation;

•diplomatic correspondence;

•opinions of national legal advisers;

•practice of international organisations.

The list was not intended to be exhaustive but to provide a basis for discussion.25

There is some disagreement as to whether, for the purpose of the formation of customary law, state practice should consist merely of concrete actions, or whether it may also include abstract verbal, ie written or oral, statements of state representatives, or their votes, at diplomatic conferences, or in UN bodies. Judge Read’s dissenting opinion in the Anglo-Norwegian Fisheries case (1951), explained the restricted view of state practice in more detail:

Customary law is the generalisation of the practice of states. This cannot be established by citing cases where coastal states have made extensive claims ...

Such claims may be important as starting points, which, if not challenged, may ripen into historic title in the course of time ... The only convincing evidence of state practice is to be found in seizures, where the coastal state asserts its sovereignty over the water in question by arresting a foreign ship.26

Dr Thirlway gives a similar view:

The fact that the practice is ‘against interest’ gives it more weight than the mere acceptance of a theoretical rule in the course of discussion by state representatives at a conference, and considerably more weight than the assertion of such a rule ... Claims may be made in the widest of general terms; but the occasion of an act of state practice contributing to the formation of custom must always be some specific dispute or potential dispute.

The mere assertion in abstracto of the existence of a legal right or legal rule is not an act of state practice ... Such assertions can be relied on as supplementary evidence both of state practice and of the existence of the opinio juris.27

Such views regard abstract statements as less, or not at all, relevant, apparently due to a reluctance to accept the notion that one body or conference could make law. However, states themselves do regard comments at conferences as

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25(1950) ILC Yearbook at pp 368–72.

26Anglo-Norwegian Fisheries case [1951] ICJ Rep at p 116.

27International Customary Law and Codification, 1972, Leiden: AW Sijthoff at p 64.

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constitutive of state practice and the courts do refer to abstract statements when identifying a customary rule. Also the term ‘practice’ in Article 38 is general enough to cover any act or behaviour of a state and it is not clear in what respect verbal acts originating from a state could not be considered behaviour of a state. It is also the case that the traditional evidence of state practice – diplomatic notes, instructions to state representatives – are often abstract and verbal. It could be argued that the restricted view of state practice is more compatible with a time when means of communication were much slower and there was less interaction between states. In the past, too, there has been a difficulty in obtaining evidence of state practice in situations not involving concrete actions. It is submitted that today such difficulties are no longer as great. Satellite communication and the development of techniques of information gathering and storage have made the collection of evidence of what states say far easier.

Of course, when using statements as evidence of state practice it is necessary to look at the context and the manner in which they were made. Consideration must be given to whether they were made de lege lata (about the law that is in force) or de lege ferenda (about the law which it is desired to establish), ‘against’ or ‘not against interest’, or as trading ploys. Statements made de lege lata and against national interest are likely to provide more compelling evidence than those made de lege ferenda or supporting national interest. It is not always easy to discover a state’s true motives behind statements. It may be argued that it is unnecessary to look at motives, since whatever a state feels or believes when making a statement, other states may come to rely on the statement and the original state may become estopped from altering its position.

A further question concerns whether written texts such as conventions, ILC drafts, resolutions, etc can be regarded as state practice. There seems no difficulty in regarding treaties as state practice, providing it is remembered that state practice must be accompanied by opinio juris for the creation of customary law. In the North Sea Continental Shelf cases the ICJ stated that ‘a very widespread and representative participation in the convention might suffice of itself’ for a conventional rule to generate customary law – but it seems clear that opinio juris has to be demonstrated beyond mere contractual obligation in such cases. Mere participation in a conference and votes on single draft rules possess little value as practice, although votes on the draft text are of much more use but usually only when accompanied by statements and explanations.

In the end, one of the main problems in evaluating the evidence for state practice is trying to ascertain what states actually do – their practice is not always consistent. For example if one were looking at the law relating to military intervention in the internal affairs of other states does one look at USSR practice in Afghanistan in 1980 which was denounced by the USA or at USA practice in Grenada in 1983 which was denounced by the USSR; how does one reconcile a reluctance to intervene militarily in ‘Yugoslavia’ with military action taken against Iraq? It is exactly this point that the critics of the traditional view of custom wish to explore further. They are concerned to try to identify the basis on which the ICJ and others applying international law make decisions about conflicting state practice.

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One final point should be made here. Although discussion has been of ‘state practice’ this should not be taken to mean that it is only the behaviour of states which is of interest. The practice of international organisations and even of individuals may well be taken into account in the attempt to establish the existence of a rule of customary international law.

3.4.2.2 The extent of the practice

The formation and existence of a customary rule requires general state practice. In the North Sea Continental Shelf cases the ICJ postulated that ‘state practice ...

should ... have been extensive’. The term ‘general’ indicates that common and widespread practice is required, although universal practice is not necessary. It seems also that practice must be representative in the sense that all the major political and socio-economic systems should be involved in the widespread practice. This marks a shift away from the position before the First World War when Professor Westlake could argue that to prove the existence of a rule of custom:

... it is enough to show that the general consensus of opinion within the limits of European civilisation is in favour of the rule.28

If practice is not widespread or general it may still give rise to a local or regional customary rule/special rule, as was argued, unsuccessfully, in the Asylum case (1950). In that case, the ICJ held that before state practice could be acknowledged as law, it had to be in accordance with a constant and uniform usage practised by the states in question. The case concerned political asylum – after an unsuccessful rebellion in Peru one of the leaders was granted asylum in the Colombian embassy in Lima. Columbia sought a guarantee of safe conduct of the leader out of Peru which was refused. Columbia took the matter to the ICJ and asked for a ruling that Columbia, as the state granting asylum, was competent to qualify the offence for the purposes of granting asylum – it argued for the ruling on the basis of treaty provisions and American law in general – ie local/regional international custom. The court found that it was impossible to find any constant and uniform usage accepted as law. There was too much fluctuation and inconsistency.29

However inconsistency per se is not sufficient to negate the crystallisation of a rule into customary law – the inconsistency must be analysed and assessed in the light of such factors as subject matter, the identity of the states practising the inconsistency, the number of states involved and whether or not there are existing rules with which the alleged rule conflicts.

The practice of specially affected states is also often significant – for example in the North Sea Continental Shelf cases it was coastal states with a continental shelf which were specially affected; the practice of landlocked states was not significant. However, it is not true to say that if all affected states follow a particular practice then a rule of customary law comes into effect, since the practice of non-affected states may be sufficiently inconsistent to prevent the

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28Westlake, International Law, Part I, 1904, Cambridge: Cambridge University Press.

29For a successful assertion of a local/special custom see the Right of Passage case [1960] ICJ Rep 6.

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formation of a rule. It may be said that what is most significant is the adherence to a rule by all those states who had the opportunity to engage in such practice.

3.4.2.3 The practice of dissenting states and persistent objectors

If, and when, certain patterns of practice are emerging, or have emerged, states may wish to diverge or dissent from such practice. States may dissent from a customary rule from its inception onwards. The feasibility of such dissent was acknowledged by the ICJ in the Anglo-Norwegian Fisheries case (1951). The case concerned the manner in which Norway calculated its territorial sea and the Court found that Norway was not bound by the existing general rules of customary law relating to the matter. A persistent objector is not bound by the eventual customary rule if the state fulfils two conditions:

1The objections must have been maintained from the early stages of the rule onwards, up to its formation and beyond.

2The objections must have been maintained consistently, since the position of other states that may have come to rely on the position of the objector, has to be protected. The objector should not be able to rely on his own inconsistencies. Thus if a state objects and at other times invokes the rule, it will no longer be entitled to be regarded as a persistent objector. In all cases the persistent objector bears the burden of proving its exceptional position.

It may be that states dissent from a customary rule after its formation. Their position is untenable because other states have come to rely on the ‘subsequent objector’ originally conforming to the rule. Also, general customary law is binding on all states and cannot be the subject of any right of unilateral exclusion exercisable at will by any one state in its own favour. It should be noted, however, that a large number of subsequent objections may lead to desuetude or modification of the rule. It should also be noted that acquiescence over a period of time to an apparent breach of a general customary rule will lead to the result that the apparent breach cannot be challenged by those states acquiescing in it.

There has been some discussion regarding the situation of newly independent states. Such states have not participated in the creation of customary rules already in force when they come into existence, nor have they had any opportunity to oppose the rule’s formation. It is open to the new state to contest the validity of customary rules or dispute their interpretation but it has no right to refuse to observe such rules, save in regard to those states which have expressly agreed to their waiver. When a new state begins to enter into relations with other states it must be taken to accept the rules of international law which are then in force. When a state applies for membership of the UN it must declare its acceptance of the principles of the Charter, the first purpose of which is the settlement of disputes ‘in conformity with the principles of justice and international law’ (Article 1(1)).

3.4.2.4 Duration of practice

In the North Sea Continental Shelf cases, the ICJ held that:

Even without the passage of any considerable period of time, a very widespread and representative participation in the (practice) might suffice of itself ...

Although the passage of only a short period of time is not necessarily, of itself, a

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bar to the formation of a new rule of customary law ... within the period in question, short though it might be, state practice ... should have been both extensive and virtually uniform.

There is no set time limit and no demand that the behaviour should have existed since time immemorial. The relative unimportance of time was highlighted by the ICJ in the North Sea Continental Shelf cases. The cases involved the Federal Republic of Germany, Denmark and Holland and a dispute over the continental shelf. Denmark and Holland argued that the equidistance principle which was contained in the Convention on the Continental Shelf 1958 was customary law. The two states had argued that even if no customary rule existed at the time of the Convention, a rule had since come into being, partly as a result of the impact of the Convention, and partly on the basis of subsequent state practice. The Court was therefore required to look at the time requirement and it ruled, in rejecting their argument, that although the passage of only a short period of time is not necessarily, or of itself, a bar to the formation of a new rule of customary international law, an indispensable requirement would be that the practice of states whose interests are specially affected, should have been extensive and virtually uniform.

The length of time required to establish a rule of customary international law will therefore depend on other factors pertinent to the alleged rule. If, for example, the rule is dealing with subject matter about which there are no previously existing rules, then the duration of practice required is less than if there is an existing rule to be overturned. Time has also become less important as international communication has improved – it is much easier to assess a state’s response to an alleged rule than it was in the past.

3.4.3 The psychological element

In addition to the material element an alleged rule of customary international law also requires a psychological element, otherwise known as opinio juris sive necessitatis. State practice must occur because the state concerned believes it is legally bound to behave in a particular way – customary law must be distinguished from mere usage. The Statute of the International Court refers to ‘a general practice accepted as law’. The essential problem then becomes one of burden and standard of proof. The position is probably as follows – the proponent of a custom has to establish a general practice and, having done this, must show that the general practice is due to a feeling of legal obligation. In many cases the International Court has been willing to assume the existence of an opinio juris on the basis of evidence of a general practice, or the previous determinations of the Court or other international tribunals (for example in the Gulf of Maine case (1984)). However, in a significant minority of cases the Court has adopted a more rigorous approach and has called for more positive evidence of the recognition of the validity of the rules in question. The first occasion where such an approach was taken was in the Lotus case (1927) where the Court said:

Even if the rarity of the judicial decisions to be found among the reported cases were sufficient to prove in point of fact the circumstances alleged by the agent for the French government, it would merely show that states had often, in practice,

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abstained from instituting criminal proceedings, and not that they recognised themselves as being obliged to do so; for only if such abstention were based on their being conscious of a duty to abstain would it be possible to speak of an international custom. The alleged fact does not allow one to infer that the states have been conscious of having such a duty; on the other hand ... there are other circumstances calculated to show that the contrary is true.

More recently the ICJ stated:

For a new customary rule to be formed, not only must the acts concerned amount to a settled practice, but they must be accompanied by the opinio juris sive necessitatis.30

The generally held view of customary law, which has been endorsed by the International Court of Justice,31 is that the creation of a rule of customary international law postulates:

... two constitutive elements: (1) a general practice of states and (2) the acceptance by states of the general practice as law.32

...

The precise definition of the opinio juris, the psychological element in the formation of custom, the philosophers’ stone which transmutes the inert mass of accumulated usage into the gold of binding legal rules, has probably caused more academic controversy than all the actual contested claims made by states on the basis of alleged custom, put together. A present-day writer may be understandably reluctant to call upon his readers to devote further time to this juridical squaring of the circle, but it is impossible to discuss the future of customary law without some study of the elements which are regarded as going to its making.

The simple equation of the opinio juris with the intention to conform to what is recognised, at the moment of conforming, as an existing rule of law has been exposed to the objection of Kelsen and others which, on its own terms, is unanswerable – that it necessarily implies a vicious circle in the logical analysis of the creation of custom. As a usage appears and develops, states may come to consider the practice to be required by law before this is in fact the case; but if the practice cannot become law until states follow it in the correct belief that it is required by law, no practice can ever become law, because this is an impossible condition. Nor does the avenue of escape indicated by the tag communis error facit jus, ie the argument that the belief, even the mistaken belief, of states in the existence of a rule of law requiring them to act, or refrain from acting, in a certain way, is sufficient to create the rule believed in, have many adherents.

The extreme opposite view, the theory that the establishment of international custom does not require opinio juris at all, but that established usage is sufficient without evidence of states of mind, has also comparatively few supporters.33 As Professor Zemanek has observed,34 while the requirement of opinio juris does

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30ICJ in Nicaragua v US (Merits) case (1986).

31See particularly Continental Shelf cases [1969[ ICJ Rep at p 44.

32Schwarzenberger, A Manual of International Law, 1967, London: Stevens at p 32.

33See for example, Kelsen, ‘Théorie du droit international coutumier’, Revue internationale de la théorie du droit, 1939, p 253ff; Guggenheim, Lehrbuch des Volkerrechts, 1948, pp 46–47; Les deux éléments de la coutume en droit international, Etudes en l’honneur de G Scelle, Vol 1, p 275; ‘Principes de droit international public’, 80 Receuil des Cours, 1952–I, at pp 70–72.

34‘Die Bedeutung der Kodifizierung des Volkerrechts für deine Anwerdung’, in Festschrift Verdross, 1971, p 565 at p 574.

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undoubtedly give rise to many problems in practice, particularly with regard to proof of its existence, to assert that it is wholly unnecessary is to ‘throw out the baby with the bathwater’. Furthermore, it is admittedly difficult to distinguish between usage which has not (apart from cases, such as the Right of Passage case before the International Court of Justice,35 in which the question is largely or entirely one of generality or consistency of practice), without allowing the psychological element in the creation of custom to creep back into the discussion by a devious route and under another name.36

A proposal for an interpretation of the traditional concept of the opinio juris which would not be subject to objection that it creates a circulus inextricabilis was advanced by Mr IC MacGibbon in 1957.37 Mr MacGibbon starts by drawing attention to the importance of distinguishing between customary rules expressed as rights and customary rules expressed as obligations, and argues that the opinio juris is principally, if not wholly, of importance from the latter standpoint.

It is only with difficulty that it can be conceived that a practice motivated by reasons of convenience or self-interest would have been initiated or evolved under the conviction on the part of the states participating that such a practice was in conformity with the law, far less that it was enjoined by the law, although such consideration may well apply to the formation of a customary obligation. To hold otherwise would be to suppose that the assertion of a claim, far from being made as of right or in a state of indifference as to whether or not it was in conformity with law, was made as a matter of duty.38

The distinction is of course a valid one, and it is perfectly correct that a state can hardly be supposed to believe that customary international law requires it to assert a certain claim, as opposed to requiring it to admit or recognise the claim of some other state, made in conformity with existing law. But the distinction as expressed by Mr MacGibbon is in fact an oversimplification of the problem: for the state which asserts a claim will be guided by what it believes to be the law in fixing the extent of its claim. The opinio juris in the traditional sense does therefore have a real existence and meaning on the side of the state which asserts a right, in that it claims as much and no more as it believes to be due to it,39 that is to say, it does not make its claim because it believes that international law requires it to do so, but because it limits its claim because it believes that international law requires it to do so.40

The orthodox view is that a rule of customary law has two constitutive elements:

(i) corpus, the material or objective element, and (ii) animus, the psychological or subjective element. The corpus of a rule of customary law is the existence of a usage (consuetudo) embodying a rule of conduct. The animus consists in the

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35Right of Passage over Indian Territory (Merits), [1960] ICJ Rep at p 6.

36Cf Tunkin, ‘Remarks on the Juridical Nature of Customary Norms of International Law’ (1961) 49 Cal LR p 419 at p 476, with reference to Guggenheim’s paper (op cit n 28 above).

37‘Customary International Law and Acquiescence’, 33 BYIL at p 115.

38MacGibbon, op cit at pp 127–28.

39Of course in practice a state may, and probably will, claim more than it thinks it is entitled to, in the form of a sort of percentage to allow for objections, but this does not affect the point made above.

40HWA Thirlway, International Customary Law and Codification, 1972, Leiden: AW Sijthoff at pp 47–49.

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conviction on the part of states that the rule embodied in the usage is binding (opinio juris). This view finds expression in Article 38(1)(b) of the Statute of the International Court of Justice which speaks of the Court applying ‘international custom, being evidence of a general practice accepted as law’.

There is a school of thought, the principal exponent of which at present is doubtless Professor Guggenheim, which disputes the reality and consequently the requirement of the subjective element of opinio juris. But both the Permanent Court of International Justice and the International Court of Justice have in a number of cases stressed the importance of the subjective element of opinio juris. indeed, it should be perhaps pointed out that by the so-called ‘psychological’ element of opinio juris, it is intended to mean not so much the mental process or inner motive of a state when it performs or abstains from certain acts, but rather the acceptance or recognition of, or acquiescence in, the binding character of the rule in question implied in a state’s action or omission. It is not without reason that the Statute of the World Court speaks of ‘international custom, being evidence of a general practice accepted as law’.

However, Article 38(1)(b) of the Statute would have been even more correct if it had said ‘international custom as evidenced by a general practice accepted as law’, for it is not the custom or customary rule of international law which is evidence of the general practice, but rather the general practice accepted as law that provides evidence of the customary rule.

Indeed, it may be permissible to go further and say that the role of the usage in the establishment of rules of international customary law is purely evidentiary; it provides evidence on the one hand of the contents of the rule in question and on the other hand of the opinio juris of the states concerned. Not only is it unnecessary that the usage should be prolonged, but there need also be no usage at all in the sense of repeated practice, provided that the opinio juris of the states concerned can be clearly established. Consequently, international customary law has in reality only one constitutive element, the opinio juris. Where there is opinio juris, there is a rule of international customary law. It is true that in the case of a rule without usage, objection might be taken to the use of the term custom or customary. But whether in such a case one speaks of international customary law or an unwritten rule of international law becomes purely a matter of terminology.

It should, however, be pointed out that in municipal law it would ordinarily not be possible to have a legally binding custom without usage; for in municipal law it is not the opinio juris of individual subjects of the legal system that is decisive but the opinio juris generalis of the community, locality, trade or profession concerned as a whole. To this opinio juris generalis the general law of the community gives its blessing and lends the weight of its own authority. Such opinio juris generalis can normally be established and ascertained only through a general and usually also prolonged practice.

But in international law, the possibility of international customary law without usage becomes obvious if it is remembered that in international society states are their own law-makers. From the analytical point of view, the binding force of all rules of international law ultimately rests on their consent, recognition, acquiescence or the principle of estoppel. If states consider themselves bound by a given rule as a rule of international law, it is difficult to see why it should not be treated as such insofar as these states are concerned, especially when the rule does not infringe the right of a third state not sharing the same opinio juris. The Asylum case and the Right of Passage case have shown that it is possible for such opinio juris to exist among a limited number of states or even between two states

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so that, besides rules of universal international customary law, one finds also local and even bipartite international customary law.

From this point of view, there is no reason why an opinio juris communis may not grow up in a very short period of time among all or simply some members of the United Nations with the result that a new rule of international law comes into being among them. And there is also no reason why they may not use an Assembly resolution to ‘positivise’ their new common opinio juris ...

... when a General Assembly resolution proclaims principles recognised, albeit not long since, by members of the United Nations as principles of international law, and is adopted unanimously, it represents the law as generally accepted in the United Nations. In such an event, the binding force of these principles comes not from the resolution, but from their acceptance by member states as part of international law. They are, therefore, binding even before the resolution, although the resolution helps to establish their existence and contents.41

Discussion of custom usually takes place in the context of discourse about sources. For a positivist (and most international lawyers are more or less positivists today), what this means is process: we seek to identify the types of procedure which, if carried out by authorised actors, create law for members of the society in question ...

... What characterises [custom], above all, is its very lack of formality. So to discuss customary law in terms of elements, steps in its creation, and so on is to impose on it a framework which in a sense falsifies its nature. The problem is exacerbated by the modern jurist’s unfamiliarity with customary law outside the international sphere. Not so very long ago, the general custom of the realm, the region, or the municipality was an important source of law throughout Europe, as well as in other places; but it came to be replaced by statute law and (to a greater or lesser extent) judicial precedent. True, customary law lingers on in parts of Africa and elsewhere, but even there it has become somewhat subordinated to the modern, ‘Western’ approach. So most commentators about the sources of international law slip easily into a formalistic mode of analysis without stopping to ask themselves whether the technique is suitable to the phenomenon under consideration. It is submitted that, mutatis mutandis, the study of domestic customary law societies, past and present, can afford useful insights into the nature of customary law ...

There is another methodological trap of which one should beware. Because in modern municipal societies jurisdiction is compulsory, it is at least feasible (if not wholly correct) to think of law in terms of what a judge will do; and in few areas is this more marked than in the doctrine of sources, where the question is often reduced to an investigation of what processes a judge would regard as capable of creating binding law. But it should not be forgotten that, in the international system, where jurisdiction is not compulsory, adjudication is the exception, not the rule. The more typical decision-maker is the government official, engaged either in advising his or her own government, or in negotiating with others. The difference in the observational standpoint has the following consequence for our topic. At least in theory, if the status of an alleged rule as customary law is challenged before a tribunal, the judge or arbitrator has to decide whether the processes for the creation of custom had been completed by the critical date.

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41Bin Cheng, ‘United Nations Resolutions on Outer Space: “Instant” International Customary Law?’, in Bin Cheng (ed), International Law: Teaching and Practice, 1982, London: Stevens at pp 249–52.

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Government decision-makers, however, need not be so objective; whilst they may well want to find out how much support the practice has attracted up until now, if it is one which they wish to follow on its merits they will probably do so, even if the rule has not yet ‘crystallised’...

Some identify the subjective element in custom as the state’s will (or several or all states’ will) that the practice become a rule of law: in other words, with consent to the (would-be) rule. Proponents of this, voluntarist, approach tend to equate the creation of custom with tacit agreement: just as treaties are the written, formal expression of states’ will, so custom is its informal manifestation. Others reject the voluntarist thesis, preferring to regard the subjective element as a belief – a belief in the legally permissible or obligatory character (as the case may be) of the conduct in question: opinio juris sive necessitatis, or opinio juris as it is known for short.

The jurisprudence of the World Court has certainly failed to still the controversy, and proponents of both theories can cite judgments which expressly or impliedly support (or appear to support) their contentions ...

OPINIO JURIS SIVE NECESSITATIS

Literally, the phrase means ‘belief (or opinion) of law or of necessity’. This does not make much sense in English, and in fact its clumsiness as a piece of Latin arouses the suspicion that it is not Roman at all. The present writer has not found it in the Digest or other classical writings on Roman law, and although the Glossators and post-Glossators have not been exhaustively combed through, the expression does not appear to have much of a pedigree in Roman law. The first person to use the complete phrase seems to have been Geny in 1919,42 though, as Guggenheim noted,43 one finds parts of the phrase or something like it in the writings of the German historical school in the late 18th and early 19th centuries. We shall return to the historical school later. So far as specifically international law is concerned, the expression does not seem to have been used by any of the so-called ‘fathers’ of international law, and the earliest use of the concept – though not the precise phrase – that the present writer has found in this context is in Rivier in 1896.44 The idea was quickly adopted by many others, however.

It is quite common to dress up legal maxims and the like in Roman robes in order to give them an air of respectability, though only too often the toga can muffle thought. In this case, the robes seem not even to be genuine, and it is submitted that the linguistic incoherence of the phrase opinio juris sive necessitatis reflects a certain incoherence of the thought behind it.

What does opinio juris sive necessitatis mean, or what should it mean, in the context of international law? At this point, it may be helpful to offer a working translation or definition. It is a belief in (or claim as to) the legally permissible or

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42Méthode d’interpretation et sources en droit privé positif, 2nd edn, 1919, Paris: Librairie générale de droit et de jurisprudence at pp 319–24, 360.

43‘Contribution à l’histoire des sources du droit des gens’ (1958–II) 94 Recueil des Cours pp 1, 52; id, ‘L’origine de la notion de la opinio juris sive necessitatis comme deuxième élément de la coutume dans l’historie du droit des gens’, in Hommage d’une génération de juristes au Président Basdevant, 1960 at p 258.

44Principe du droit des gens, Vol 1 p 35. But there are perhaps earlier hints of this in Savigny, System des heutigen Romischen Rechts, Vol 1, 1840, Heidelberg: Mohr at pp 32–34.

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obligatory nature of the conduct in question,45 or of its necessity. We shall return later to the part of the definition which refers to necessity.

On the subject of belief, it may also be convenient at this juncture to refer to an observation made by Virally,46 and echoed by D’Amato47 and Akehurst,48 amongst others. We cannot know what states believe, it is suggested. First of all states, being abstractions or institutions, do not have minds of their own; and in any case, since much of the decision-making within governments takes place in secret, we cannot know what states (or those who direct or speak for them) really think, but only what they say they think. There may be something of an exaggeration here. In some instances, we can discover their views because the opinions of their legal advisers or governments are published.49 Furthermore, it will be suggested later that the express or presumptive understandings and beliefs of the international community about the rules of international law are in certain circumstances relevant. We should not speak of a psychological element in custom, but of a subjective one, for it is more a question of the positions taken by the organs of state about international law, in their internal processes50 and in their interaction with other states, than of their beliefs. This viewpoint is not unrelated to the well-known observation of McDougal that the customary process is one of claim and response, where the legal claims and the responses thereto can be implied in the conduct concerned without necessarily being expressed ...

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45The bipolar nature of legal relations means that if X has a legal right (eg to compensation), Y will have a duty to pay; and if X has a liberty (eg of innocent passage through Y’s territorial sea), Y will have no right to complain and an obligation not to interfere with that passage. These ideas can be expressed in terms of obligatoriness and permissibility. Cf Mendelson ‘State Acts and Omissions as Explicit or Implicit Claims’, in Le Droit international au service de la paix, de la justice et du développement, 1991, Mélanges Michel Virally at p 373. It is hard to follow MacGibbon’s suggestion that the role of opinio juris should be limited to positive conduct.

46’The Sources of International Law’ in Sorensen (ed), Manual of Public International Law, 1968, London: Macmillan at pp 116, 133–4.

47The Concept of Custom in International Law, 1971, Ithaca: Cornell University Press at pp 35–39. This volume, which enjoyed a considerable vogue, particularly in the United States, for some years after its publication, propounds a number of unconventional ideas, but unfortunately not a few of them seem unfounded or overstated. Reasons of space preclude a complete examination here, but among these questionable ideas are the following. (1) The equation or substitution of opinio juris with a theory of articulation, whereby if any entity, be it a state, international organisation, or scholar, has articulated what it, he or she considers to be a new rule of customary law, and that articulation is followed at any time thereafter by an act of state practice – apparently even a single one – then that will found the rule, even if the state which performed the act made no connection between its own conduct and the articulation by another – so long as it was aware of it, or had reason to be (pp 74–87). (2) So far as concerns the material element, the author appears to consider that treaty promises constitute (without more) qualifying state practice, but unilateral acts, such as legislation, cannot – a strange reversal (pp 89–91). (3) A mechanistic form of reasoning (pp 91–8) leads him to suggest that just two precedents can constitute a (semble general) customary rule. This seems far too crude. A fortiori the suggestion that, in litigation, a single precedent might well suffice. (4) The legal significance of protest is downgraded (pp 98–102) in a manner belied by the practice of states and the decisions of international tribunals.

48’Custom as a Source of International Law’ (1974–75) BYIL 47 p 1 at pp 36–37.

49Though admittedly this is done only on a partial and selective basis and often only long after the event, and though it must also be conceded that the opinion of a legal adviser does not invariably become that of the government.

50Including the communication of governments to national legislatures and courts, and the express or implicit prises de position about rules of international law by national courts and legislatures in the exercise of their functions.

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Summary and conclusions

1A state’s consent to a rule will be a sufficient explanation of its being bound by it, and its refusal at the formative stage of a rule a reason why it is (probably) not bound. But the voluntarist approach does not provide a satisfactory explanation of the whole of customary law. In particular, it does not provide a convincing reason why states who have not truly participated in the formation of a rule should be bound by it – though undoubtedly they are.

2Opinio juris sive necessitatis, for its part, is a phrase of dubious provenance and uncertain meaning. The concept was originally used by the historical school of jurisprudence to explain the content of substantive national law, and was transferred to the context of international law around the turn of the present century. It does have a role to perform in explaining why certain types of conduct constitute mere comity or otherwise do not count as precedents. It is not certain, however, that these functions could not be as well or better performed by using the language of claim and response.

3In any case, there seems analytically to be no particular reason to insist on proof of the presence of opinio juris in the standard type of case, where there is a constant, uniform and unambiguous practice of sufficient generality, clearly taking place in a legal context and unaccompanied by disclaimers, with no evidence of opposition at the time of the rule’s formation by the state which it is sought to burden with the customary obligation, or by another state or group of states sufficiently important to have prevented as general rule coming into existence at all.

The adoption of the present thesis would bring doctrine more into line with the practice of states and of international tribunals than the mechanical repetition of the necessity of the two elements. As a matter of theory, too, it is submitted that this approach could be justified in terms of the creation of legitimate expectations. This is not the place for a complete explanation of this author’s theory of legitimate expectations which underlie the sources of international law. Perhaps it will suffice for the present to say that if a state actually consents to a rule, a legitimate expectation will be created that it will comply with it, just as a disclaimer or persistent dissent at the appropriate time will prevent such an expectation being created. And where there is a constant and uniform practice of sufficient generality, in a legal context, it seems legitimate for members of the community to expect all others to continue to observe that practice. And finally, as a matter of policy, the solution proposed seems a reasonable one. If a relevant practice is sufficiently widespread, it ought to become law, because otherwise the convoy will have to move at the pace of the slowest. To require proof of consent

– or even opinio juris on the part of each and every state – seems excessive and unnecessary. At the same time, the sovereignty and the reasonable interests of states can be safeguarded. If a sufficient number of like-minded states object to a new practice, they can prevent it from ever becoming general law. And in addition, the individual state can individually opt out, at the formative stage, by becoming a persistent objector. By these means, customary law can continue to make a useful contribution to the formation of international law; and given that the treaty process has disadvantages as well as advantages, it is essential that custom continues to make that contribution.51

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51M Mendelson, ‘The Subjective Element in customary International Law’ (1995) 66 BYIL at pp 177, 178–81, 194–96, 207–8.

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3.4.4 Treaties as evidence of customary law

The issue here is the extent to which a multilateral treaty can be used as evidence of customary international law. It is a general rule of international law which is confirmed in Article 34 of the Vienna Convention on the Law of Treaties 1969 that treaties cannot bind third parties without their consent. If a state wishes to enforce the provisions of a treaty against a non-party it is necessary to argue that the provisions of the treaty are valid as rules of customary international law. Two possible situations arise:

1Where the treaty is intended to be declaratory of existing customary international law;

2Where the treaty is constitutive of new law.

If the treaty on its face purports to be declaratory of customary international law or if it can be established that it was intended to be declaratory of customary international law, then it may be accepted as valid evidence of the state of the customary rule. If the treaty at the time of its adoption was constitutive of new rules of law, then the party relying on the treaty as evidence of customary law will have the burden of establishing that the treaty has subsequently been accepted into custom.

The ICJ in the North Sea Continental Shelf cases recognised that it is possible for a treaty to contain norm-creating provisions which become accepted by the opinio juris and bind non-parties just as much as parties to the convention but the court did lay down a series of conditions:

1The convention provision must be of a fundamentally norm-creating character such as could be regarded as forming the basis of a general rule of law;

2There must be widespread and representative participation in the convention particularly of those states whose interests are specifically affected;

3There must be opinio juris reflected in extensive state practice virtually uniform in the sense of the provision invoked.

The following point should also be noted:

Since treaties and custom are on the same footing, it follows that the relations between rules generated by the two sources are governed by those general principles which in all legal orders govern the relations between norms deriving from the same source: lex posterior derogat priori (a later law repeals an earlier law), lex posterior generalis non derogat priori speciali (a later law, general in character does not derogate from an earlier law which is special in character), and lex specialis derogat generali (a special law prevails over a general law).52

3.5General principles of law

The general object, then, of inserting the phrase [‘general principles of law recognised by civilised nations’] in the statute seems to have been, essentially, to make it clear that the Court was to be permitted to reason, though not to

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52 Cassese, International Law in a Divided World, 1986 Oxford: Clarendon Press at p 180.

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legislate, and by, for instance, the application of analogies from the law within the state, to avoid ever having to declare that there was no law applicable to any question coming before it. This was a problem which troubled the Continental jurists who assisted in the drafting of the Statute, but did not trouble the AngloSaxons, who of course expected judges to reason without express instructions.53

The prevailing view as to the meaning of Article 38(1)(c) is that it authorises the Court to apply the general principles of municipal jurisprudence, in particular of private law, in as far as they are applicable to the relations of states. It is not thought to refer to principles of international law itself, which are to be derived from custom or treaty. International tribunals will often refer to ‘well-known’ or ‘generally recognised’ principles such as the principle of the independence and equality of states. Such principles do not come within Article 38(1)(c).

[General principles] are, in the first instance, those principles of law, private and public, which contemplation of the legal experience of civilised nations leads one to regard as obvious maxims of jurisprudence of a general and fundamental character – such as the principle that no one may be judge in his own cause, that a breach of legal duty entails the obligation of restitution, that a person cannot invoke his own wrong as a reason for release from legal obligation, that the law will not countenance the abuse of a right, that legal obligations must be fulfilled and rights must be exercised in good faith, and the like.54

No decision of the Court, or indeed the Permanent Court, has yet been based explicitly upon a principle or rule of law drawn from the ‘general principles of law recognised by civilised nations’ referred to in Article 38, para 1(c) of the Statute.55 It is comparatively rare for a state to base a claim before the Court on such principles, so that it is correspondingly infrequent for the Court to have occasion to refer to them for the purposes of its decision. Even where referred to

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53Clive Parry, The Sources and Evidences of International Law, 1965, Manchester: Manchester University Press at p 83.

54Lauterpacht, International Law, Vol 1, 1970, Cambridge: Cambridge University Press at p 69.

55A member of the Court has however gone on record, in an extra-judicial capacity, to the following effect:

‘The silence observed in this matter by them International Court of Justice or other international tribunals must [not] be misinterpreted as any neglect of the importance of examining the common grounds of national systems. However, as far as my experience goes, basic principles common to national legal systems are not normally disputed. The jus gentium applied by the Roman praetor peregrinus is still a reality. The main question is, however, how a generally accepted principle can provide an appropriate solution in the actual case under consideration. Studies of national legislations which have been submitted to the Court in the past are very helpful in clarifying the concepts and solutions found in national law, but usually they cannot offer precise criteria for the application and interpretation of international law in the given case. The presentation of the various solutions of national legislations paraphrasing the basic principle involved, would often not be in conformity with the style of a judgment, the reasoning of which must proceed in a continuous chain of thought and argument to the operative part. I admit, however, that it would be welcomed not only by the parties but also by the international legal world if the reasoning of judgments and advisory opinions were to explain that the Court had examined, by comparative methods, the assertion – sometimes boldly stated – that a general principle of law, having a specified meaning and significance, forms part of binding general international law’: Mosler, ‘To what extent does the variety of legal systems of the world influence the application of general principles of law within the meaning of Article 38(1)(c) of the Statute of the International Court of Justice?’, International Law and the Grotian Heritage, 1985, The Hague: TMC Asser Instituut at p 180.

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by a party to proceedings, the general principles tend to be employed as something of a makeweight or last resort, a supplementary argument in case the contentions based on customary law or treaties fail to convince: with the result that the Court hardly ever needs to refer to them. On the other hand, individual Members of the Court invoke general principles more frequently: Judge Ammoun was particularly attached to them, though he had strong objections to the use in the Statute of the term ‘civilised nations’.

...

It is fairly well established that the general principles contemplated by Article 38, para 1(c) of the Statute are at least primarily those which reveal themselves in the consistent solutions to a particular problem adopted in the various systems of municipal law – what Mr Elihu Root called, during the discussions of the 1920 Committee of Jurists, those which were ‘accepted by all nations in foro domestico’.56 It is necessary, though not always easy, to distinguish these principles from, on the one hand, what Sorensen has called ‘les principes fondamentaux de la structure du droit international’57 ... and from, on the other hand, mere arguments from analogy by reference to institutions or rules found in one or more systems of municipal law. These discussions were the subject of much argument between the parties in the Right of Passage case.58

The general principles of law recognised by civilised nations’ form part of the law to be applied by the permanent forum of the family of nations, the International Court of Justice ...

[Article 38 of the Statute of the International Court of Justice] is the same as Article 38 of the Statute of the Permanent Court of International Justice, except for an alteration in the numbering of the paragraphs and sub-paragraphs59 and the addition of a few words of no great practical importance in the introductory phrase. The mention of ‘general principles of law recognised by civilised nations’ (‘les principes generaux de droit reconnus par les nations civilisées’) as part of the law to be applied by the Permanent Court of International Justice at once provoked considerable discussion among writers, in which the most divergent views on the character of such principles were expressed.

Some writers consider that the expression refers primarily to general principles of international law and only subsidiarily to principles obtaining in the municipal law of the various states.60 Others hold that it would have been

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56Procès-verbal of the Committee, p 335.

57Les Sources du droit international, p 116. The interpretation of Article 38(1)(c) as restricted to principles derivable from municipal law recognition does not of course signify the exclusion of other general principles form the corpus of law applicable by the Court. Mosler, following Anzilotti, observes that the more basic principles need no transformation into international law, whereas the principles commonly accepted in municipal systems do need to be so transformed, hence the inclusion of Article 38(1)(c) in the Statute: ‘Bedeutungswandel in der Anwendung “der van den zivilisierten Staaten annerkannten allgemeinen Rechtgrundsatze”’, Pensamiento juridico y sociedad internacional, 1986, Madrid: Melanges Treyol Serra at pp 7–76.

58H Thirlway, ‘The Law and Procedure of the International Court of Justice 1960–1989’ Part Two (1990) 61 BYIL at pp 110, 114.

59In the Statute of the PCIJ the paragraphs were not numbered, while the sub-paragraphs were numbered by arabic figures. The present Art 38 1(c) was, therefore, referred to, under the old statute, as Art 38 I 3, or often Art 38 3. For the sake of convenience, the new numbering will be used in this work even when referring to the Statute of the PCIJ.

60Anzilotti, (1929) 1 Cours de Droit International at p 117. Hudson, The PCIJ 1920–42, 1943, New York: Macmillan at p 611. Castberg ‘La methodologie du droit international public,’ (1933) 43

Recueil La Haye p 313 at p 370 et seq. Morellie ‘La théorie générale du procès international’, 61 ibid, p 253 at p 344 et seq.

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redundant for the Statute to require the Court to apply general principles of international law, and that, therefore, this provision can refer only to principles obtaining in municipal law.61 Some writers even maintain that the expression is intended to refer exclusively to principles of private law.62

A difference of opinion also exists as to whether ‘the general principles of law recognised by civilised nations’ are or are not principles of natural law. While certain authors think they are, others deny categorically that they have any connection with natural law. A leading exponent of the modern doctrine of natural law believes, however, that while they are not actually principles of natural law, they are derived from it.63

Nor do authors agree as to whether ‘general principles of law’ are part of the international legal order, simply because it is a legal order, or because there exists a rule of customary international law according to which such principles are applicable in international relations. Moreover, some writers maintain that ‘general principles of law’ do not form part of the law to be applied by the World Court by virtue of the enabling provision in its Statute.

The greatest conflict of views concerns the part played in international law by these ‘general principles’. While some writers regard them merely as a means for assisting the interpretation and application of international treaty and customary law, and others consider them as no more than a subsidiary source of international law, some modern authors look upon ‘general principles’ as the embodiment of the highest principles – the ‘superconstitution’ of international law.

Interesting though this discussion of the character of such ‘general principles’ may be in the theory of international law, it is even more important to know what they in fact represent. For this reason, the purpose of the present study is not to ascertain what they ought to be theoretically, or how they should be classified, but is primarily intended to determine what they are in substance and the manner in which they have been applied by international tribunals.

As an introduction to this study, the genesis of Article 38(1)(c) of the Statute of the World Court may usefully be examined. In February 1920 at its second meeting, the Council of the League of Nations appointed an Advisory Committee of Jurists for the purpose of preparing plans for the establishment of

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61Strupp, ‘Le droit de juge international de statuer selon l’équité’ 33 ibid (1930) p 357 at pp 474–75. Scerni, I principi generali di diretto riconosciuti dala nazioni civili, 1932, p 13 et seq.

62Cf Lauterpacht, Private Law Sources and Analogies of International Law, 1927, Cambridge: Cambridge University Press at p 71: ‘Those general principles of law are for the most practical purposes identical with general principles of private law.’ See also ibid, p 85. For a criticism of this exclusive approach, see Le Fur, ‘Règles générales du droit de la paix’ (1935) 54

Recueil La Haye p 5 at pp 206–07. In his The Function of Law in the International Community, 1933, Lauterpacht admitted that they included also general principles of public law, general maxims and principles of jurisprudence.

Graspin, Valeur internationale des principaux generaux du droit, 1934, pp 64–66. Ripert ‘Règles du droit civil applicables aux rapports internationaux (1933) 44 Recueil La Haye at p 569. Ripert believed that they were principles of municipal law (jus civile of the Romans): he seemed to have allowed it subsequently to assume its modern meaning of private law by tracing the evolution of the meaning of the term in France (p 583). His main object, however, was to ascertain which principles of private law were really principles applicable in all legal systems (p 569) and he did not appear to maintain that the latter were exclusively to be found in private law.

63Le Fur, ‘La coutume et les principes generaux du droit comme sources du droit international public’, (1936) 3 Recueil Geny p 362 at p 368. The relevant passage was almost textually reproduced in the same authors ‘Règles generales etc’ loc cit p 205.

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the Permanent Court of International Justice provided for in Article 14 of the Covenant of the League of Nations. This Advisory Committee held its meetings from June 16 to July 24, 1920 and was able to present its Report together with the Draft Statute of the Court to the Council of the League at its eighth session (July 30–August 5, 1920).

Before the Advisory Committee actually met, a Memorandum was submitted to it by the Secretariat of the League of Nations, together with a number of draft schemes prepared by states and individuals, relating to the establishment of a World Court. In so far as the law to be applied by the Court was concerned, it will be found that none of these drafts took a positivist64 or voluntarist65 view. Besides treaties and established rules, the Court was according to these various drafts directed to apply ‘general principles of law,’66 ‘general principles of law and equity,’67 ‘general principles of justice and equity,’68 or even ‘rules which, in the considered opinion of the Court, should be the rules of international law’.69

It was, therefore, quite in line with these drafts, which may be considered as a fair indication of the general opinion on the subject, that, when the question of the law to be applied by the Court came up for discussion in the Advisory Committee of Jurists, Baron Descamps, Chairman of the Committee, proposed that, after conventions (clause 1) and commonly recognised custom (clause 2), the Court should apply ‘the rules of international law as recognised by the legal conscience of civilised nations’ (clause 3), or, as they were described in the original French version of the proposal ‘les règles de droit international telles que les reconnaît la conscience juridique des peuples civilisés.’

Mr Elihu Root, the American member of the Committee, whilst not objecting to the application by the Court of conventions and recognised custom (ie clauses 1 and 2 of the Descamps proposal) said that he ‘could not understand the exact meaning of clause 3’. He wondered whether it was possible to compel states to submit their disputes to a court ‘which would administer not merely law but also what it deems to be the conscience of civilised peoples’.

It may be apposite to point out here that although some words, which are identically spelt in French and English, can be literally transposed from one language into the other, others carry subtle but important differences in meaning in the two languages so that literal transposition becomes impossible. Thus the word ‘conscience’, which exists in both English and French, while it often conveys the same meaning in both languages, does not invariably do so. ‘Conscience’ has

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64As used in this work, ‘positivism’ denotes that school of thought which consider that law ‘properly so called’ consists only of rules derived from a ‘determinate source’ or, in other words, rendered ‘positive’ by means of a formal process.

65As used in this work ‘voluntarism’ denotes that school of thought which emphasises the element of will in the formation of legal norms, either the will of the state, in the form of a command, or the will of the subjects, as manifested by consent.

66Draft scheme of Denmark, Norway and Sweden, Art 27 II.

67German Draft Scheme, Art 35. Clovia Bevilaqua’s Draft scheme, Art 24 II. Bevilaqua’s second category of rules is in fact customary international law.

68Article 42 of the Swiss Draft Scheme establishes the following three categories: conventions, principles of international law, and the general principles of justice and equity. Article 12 of the Draft of the Union Juridique Internationale directs the court to apply ‘law, justice and equity’.

69Draft Scheme of Denmark, Norway and Sweden, Art 27 II (Alternative) Danish Draft Scheme, Art 15 II, Norwegian Draft Scheme, Art 15 II, Swedish Draft Scheme, Art 17 II, Draft Scheme of the Five Neutral Powers (Denmark, Norway, Netherlands, Sweden, Switzerland), Art 2 II.

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acquired in current English usage a primarily moral and introspective connotation – the sense of what is morally right or wrong possessed by an individual or a group as regards things for which the individual himself, or the group collectively, is responsible.

In French ‘conscience’ denotes also ‘the sense of what is right or wrong’, but not necessarily what is morally right or wrong. For instance, the French speak of ‘liberté de conscience’ for ‘freedom of belief’, thus distinguishing ‘conscience réligeuse’ from ‘conscience morale’. It follows that ‘conscience juridique’ is equally distinguishable from ‘conscience morale’. It is a familiar expression with French jurists, meaning ‘the sense of what is juridically right or wrong’.

Furthermore, although ‘conscience’ in French also implies the passing of judgment upon human actions and motives, it does not invariably mean an introspective judgment upon one’s own actions and motives. Thus ‘conscience publique’ in French merely means ‘the people’s sense of what is right or wrong’ without necessarily implying self-judgment.

For these reasons, the phrase ‘la conscience juridique des peuples civilisés’ which figured in the Descamps proposal may be translated into English as ‘the sense common to all civilised peoples70 of what is juridically right or wrong’, or as ‘the opinio juris communis of civilised mankind’.

The literal translation of the phrase by ‘the conscience of civilised nations’ would seem to have a different meaning in English, namely ‘the moral sense of right or wrong possessed by each civilised nation as regards things for which it is responsible’. And, since ‘conscience’ in English denotes an essentially moral quality, the original English translation of the Descamps proposal which spoke of the ‘legal conscience of civilised nations’, is, if not self-contradictory, at least as difficult to understand, as, indeed, Mr Root found it.

The reason why Mr Root at first objected to the Descamps proposal was certainly more substantial than one arising from a linguistic misunderstanding but a proper understanding of the original proposal is nevertheless important.

An examination of the various proposals put forward and opinions expressed during the discussion, concerning the rules of law to be applied by the Court, discloses five distinct views:

(1)First, a group of proposals refrained from indicating to the Court which rules of law it was to apply.

(2)Secondly, the various Scandinavian drafts and that of the five neutral powers inspired by the Swiss Civil Code directed the Court to apply conventions and recognised rules of international law, and, in default of such rules, to apply what, in its considered opinion, the rule of international law on the subject

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70It should be noticed that the original proposal of Descamps referred to ‘peuples civilisés’, ie ‘civilised peoples’ or ‘civilised mankind’. This is important, because the expressions ‘civilised nations’ and ‘nations civilisés’ which are now found in the English and French text of Art 38 1(c) originate from Root’s amendment to the Descamps proposal. This amendment referred to ‘civilised nations’ which was the English translation used by the Committee of Jurists for Descamps’ ‘peuples civilisés’. In fact, the earlier translation of the Root amendment also used ‘peuples civilisés in the French version. Looked at from this angle, the word ‘nation’ in Art 38 1(c) should be understood not in its politico-legal sense, as it is used in the ‘League of Nations’ ‘United Nations’ or ‘International Law’ but in its more general sense of a people, as for instance, the Scottish nation, the French nation, the Maori nation, etc. Some further support for this view may be found in the fact that, at certain stages of the drafting of the article, the word nation in clause 3 was written with a small n, while the same word in clause 4 in the sense of a country was written with a capital N.

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ought to be. The latter part of this proposal was regarded as conferring on the Court a legislative power, and, since all the members of the Committee were in agreement that a Court should not legislate, this formula did not find any favour.

(3)Thirdly, there was the proposal of Baron Descamps, which was supported by M Loder and M Hagerup and received no serious opposition except from Mr Elihu Root. In order to appreciate how much this view coincides with the fifth view which was that of Lord Phillimore’s, it must be realised that, in his proposal, Baron Descamps defined international custom as ‘pratique commune des nations, acceptée par elles comme loi’. As such, his conception of custom was much more restrictive than Lord Phillimore’s. According to the Descamps formula, both the consuetudo and the opinio juris, the two constitutive elements of a custom, have to be common to all nations. Adopting so stringent a view of international custom, it is not surprising that Baron Descamps should classify another portion of international law under a third heading, ‘les règles de droit international telles que les reconnait la conscience juridique des peuples civilisés’. While he conceived these as rules of objective justice, he limited the formula to what the opinio juris communis of the civilised world considered as rules of international law. These rules of objective justice Baron Descamps also called ‘general principles of law’, and, as an illustration of the principles he had in mind, he cited the case of the application of the principle of res judicata in the Pious Fund case by the Permanent Court of Arbitration.

(4)Fourthly, there was the original view of Mr Root who seemed ready to admit only clauses 1 and 2 of the Descamps proposal, and even entertained some doubt as to clause 2 concerning the application by the Court of commonly recognised custom. The position originally adopted by this distinguished American statesman, who had contributed so much to the establishment of the Permanent Court of International Justice, was, however, actuated more by an earnest wish to see the Statute accepted by all countries than by a strict adherence to juridical principles. In this connection, it should be borne in mind that, at the time, the Advisory Committee had agreed in principle that the compulsory jurisdiction of the Court should be accepted by all the members of the League of Nations by the very fact of adhering to the Statute of the Court. Mr Root rightly linked this aspect of the question with the rules concerning the application of law. However unconnected they may be from a juridical standpoint, their relation is certainly real and substantial from the point of view of states called upon to submit to the jurisdiction of the Court. A restrictive formula with regard to the law to be applied would, in Mr Root’s opinion, have facilitated the acceptance of the step forward in the field of jurisdiction. He was, therefore, disposed to accept the Descamps proposal in respect of all the Court’s jurisdiction other than its compulsory jurisdiction. He was even disposed to accept it, where the Court had compulsory jurisdiction, so long as the dispute concerned the extent and nature of reparation for breach of an obligation, or the interpretation of judgments, but he was not prepared to accept it where the dispute concerned questions of international law in general.

(5)Finally, there was Lord Phillimore’s amended text of the Descamps proposal, elaborated in conjunction with Mr Root, which was in fact the text adopted by the Advisory Committee. On closer examination, Lord Phillimore’s views were not so different from Baron Descamps. His attitude with regard to the rules concerning the law to be applied was even more liberal than that of Baron Descamps; for he was ready to allow that, in the absence of treaty law,

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the Court should apply the rules of international law in force ‘from whatever source they may be derived’. But, even on the assumption that, by this formula, Lord Phillimore intended the only alternative to treaty law to be customary law, his conception of international custom was much more liberal than that of Baron Descamps; for he declared that ‘generally speaking, all the principles of common law are applicable to international relations. they are in fact part of international law.’ He considered the example cited by Baron Descamps to illustrate ‘les règles de droit international telles que les reconnait la conscience juridique des peuples civilisés’, namely the principle of res judicata as one of the principles of common law. ‘This’, he said, ‘is a principle which has the same character of law as any formulated rule’. In other words, there are principles of international law in force which have not yet assumed the form of formulated rules. Indeed when questioned by Baron Descamps Lord Phillimore agreed that international law as understood by him resembled natural law. Theoretical niceties apart, there is, therefore, little practical difference between the views of Baron Descamps who held that international law included certain principles of objective justice and the views of Lord Phillimore who held that international law included all the principles of common law, which itself resembled natural law. Furthermore, Lord Phillimore declared himself generally in agreement with M Ricci-Busatti who has said that the Court should apply ‘general principles of law’. It is indeed, in this formula that the views of Baron Descamps and Lord Phillimore found their common denominator.

When, therefore, at the 15th meeting of the Committee (3 July 1920) the formula ‘the general principles of law recognised by civilised nations’ in lieu of the original clause 3 was actually proposed by Mr Root, who had in collaboration with Lord Phillimore prepared an amended text to the Descamps proposal, it was immediately agreed to by Baron Descamps and the rest of the committee. This is the origin of the present Article 38(1)(c) of the Statute of the International Court of Justice.71

DRAFT CODE OF GENERAL PRINCIPLES OF LAW

Article 1 Good faith shall govern relations between states.

In particular, every state shall fulfil its obligations and exercise its rights in good faith.

Article 2 A state is responsible for any failure on the part of its organs to carry out the international obligations of the state, unless the failure is due to vis major.

Vis major, in order to relieve a state of its obligations, must be of such a nature as to make it impossible for the state to fulfil that obligation, and this impossibility must not be imputable to the state itself.

Article 3 Responsibility involves an obligation on the part of the state concerned to make integral reparation for the damage caused, in so far as it is the proximate result of the failure to comply with the international obligation.

The state shall, wherever possible, make restitution in kind. If this is not possible, a sum corresponding to the value which restitution in kind would bear shall be paid. Whenever restitution in kind, or

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71Bin Cheng, General Principles of Law as applied by International Courts and Tribunals, 1993, Cambridge: Cambridge University Press at pp 1–14.

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payment in lieu of it, does not cover the entire loss suffered, damages shall be paid in order that the injured party is fully compensated.

The damage suffered shall be deemed to be the proximate result of an act if it is the normal and natural consequence thereof, or if it would have been foreseen by a reasonable man in the position of the author of the act, or if it is the intended result of the act.

Article 4 Any claim by one state against another shall be deemed invalid if the claimant state has, by its own negligence, failed to present the claim for so long as to give rise to a danger of mistaking the truth.

Article 5 Every tribunal has the power, in the first instance, to determine the extent of its jurisdiction, in the absence of express provision to the contrary.

Article 6 The jurisdiction of a tribunal extends to all relevant matters incidental to the principal question in respect of which it is competent, in the absence of express provisions to the contrary.

Article 7 Parties to a dispute are disqualified from acting as judges or arbitrators in such a dispute.

Where a judge or arbitrator is the national of, or has been selected by, one of the parties to the dispute, he shall not consider himself as an agent of that party, but must decide the case submitted to him impartially without fear or favour.

Article 8 In judicial proceedings, the tribunal shall ensure that both parties have an adequate and equal opportunity to be heard.

Article 9 The above provision shall not affect the right of the tribunal to decide by default, if one of the parties, without valid reason, fails to appear before the tribunal, or to defend his case.

In such an event the tribunal must decide according to the merits of the case, after satisfying itself that it has jurisdiction.

Article 10 The tribunal shall, within the limits of its jurisdiction, examine points of law proprio motu, without being limited to the arguments of the parties.

Article 11 Parties to a case must abstain from any act which might aggravate or extend the dispute and, in particular, from any measure calculated to have a prejudicial effect in regard to the carrying out of the decision to be given.

Article 12 The decision of an international tribunal is final. Any question which has been resolved by a valid and final decision may not be reopened between the same parties.

Article 13 The decision of an international tribunal is binding only upon the parties to the dispute.

Decisions on incidental or preliminary questions are only binding upon the parties to the dispute.

Article 14 A judgment may be annulled:

(a)if the tribunal which gave the judgment lacked jurisdiction or exceeded its jurisdiction;

(b)if the tribunal, or any member thereof is proved to have been guilty of fraud or corruption in connection with the particular case; or

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(c) if the tribunal failed to give both parties an equal and adequate opportunity to be heard.

Article 15 A judgment may be revised on the grounds of:

(a)manifest and essential error;

(b)after-discovered evidence; or

(c)fraud of the parties or collusion of witnesses.

Article 16 A tribunal may annul or revise its own judgment, either proprio motu, or on the application of one of the parties, for any of the reasons mentioned in the two preceding Articles provided that it still has jurisdiction over the dispute.72

3.5.1 Some examples

A number of decisions of the International Court help illustrate the nature of ‘general principles’. In the Chorzow Factory (Jurisdiction) case, the Permanent Court enunciated the principle that:

... one party cannot avail himself of the fact that the other has not fulfilled some obligation, or has not had recourse to some means of redress, if the former party has, by some illegal act, prevented the latter from fulfilling the obligation in question, or from having recourse to the tribunal which would be open to him.73

Later on in the same case, the Court observed:

... that it is a principle of international law, and even a general conception of law, that any breach of an engagement involves an obligation to make reparation.74

In a number of cases the International Court has made use of the doctrine of estoppel as recognised by a number of municipal legal systems. Perhaps the clearest example came in the Temple case involving Thailand (formerly Siam) and Cambodia, formerly part of French Indo-China. The two states were in dispute over a section of the frontier. Cambodia successfully relied on a map of 1907 which the predecessor French authorities had produced at the request of the Siamese Government. The map clearly showed the Temple area as part of French IndoChina. The Siamese authorities, far from protesting at the error, had thanked the French for preparing the map and requested a number of copies. Furthermore, in 1930, a Siamese prince paid a state visit to the disputed area and was officially received there by the French authorities. Together, these two events were seen by the International Court as conclusive and it found that Thailand was precluded by its conduct from denying the frontier indicated on the map.75

Other principles considered by the Court have included the right to bring class actions (actio popularis)76 and the doctrine of corporate personality in the

Barcelona Traction, Light and Power Company Limited case.77

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72Bin Cheng, General Principles of Law as applied by International Courts and Tribunals, 1993, Cambridge: Cambridge University Press at Appendix I.

73Chorzow Factory (Jurisdiction) case PCIJ Ser A, No 9 (1927).

74Chorzow Factory (Merits) case (1928) PCIJ Ser A, No 17 (1928).

75Temple of Preah Vihear [1962] ICJ Rep at p 1.

76South West Africa case [1950] ICJ Rep at p 128.

77[1970] ICJ Rep at p 3.

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3.5.2 Equity

Amongst these general principles it could be argued that equity, in the sense of justice and fairness, is included and in a number of cases it has been used indirectly to affect the way in which substantive law is applied. The application of equity as a general principle should not be confused with Article 38(2) which states that if both parties to a dispute agree, the court can decide a case ex aequo et bono, ie the court can apply equity in precedence to all other legal rules.

During the period under review [1960–1989] there has been a striking increase in references to equity in the work of the Court – not only in the pleadings of the parties, but in the judgments themselves; so much so that one observer has felt able to declare that ‘after 50 years of hesitation the World Court has clearly accepted equity as an important part of the law that it is authorised to apply’.78 Concepts of equity have certainly had a very extensive influence in one particular domain – that of the delimitation of maritime areas; but it is probably premature to see in the decisions of the Court even in that specific field the application of any consistent and mature theory of equity. In matters unconnected with maritime delimitation, equity has been referred to and applied sporadically, but in ways which paradoxically are easier to reconcile with classical concepts of equity than the specialised use of it in disputes of maritime areas.79

The ICJ itself has on a number of occasions indicated that it considers the principles of equity to constitute an integral part of international law. In the Diversion of Water from the Meuse case (1937), Judge Hudson declared:

What are widely known as principles of equity have long been considered to constitute a part of international law, and as such they have often been applied by international tribunals.80

Over 40 years later the ICJ confirmed this view in the Continental Shelf (Tunisia/Libyan Arab Jamahiriya) case (1982):

Equity as a legal concept is a direct emanation of the idea of justice. The court whose task is by definition to administer justice is bound to apply it ... [The Court] is bound to apply equitable principles as part of international law, and to balance up the various considerations which it regards as relevant in order to produce an equitable result.

For a particularly full discussion of the place of equity within international law readers are referred to the judgment of Judge Weeranmantry in the Case Concerning Maritime Delimitation in the Area Between Greenland and Jan Mayen (Denmark v Norway)(1993).

3.6Judicial decisions

In the event of the court being unable to solve a dispute by reference to treaty law, custom or general principles, Article 38 provides a subsidiary means of

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78Sohn, The Role of Equity in the Jurisprudence of the International Court of Justice, 1984, Mélanges Georges Perrin (1984) at p 311.

79H Thirlway, ‘The Law and Procedure of the International Court of Justice 1960–1989’ Part One (1989) 60, BYIL (1989) at p 49.

80PCIJ Ser A/B, No 70.

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judicial decisions and the teachings of the most highly qualified publicists of the various nations be employed – although the increase of treaty law has led to a decline in the use of the subsidiary source.

Judicial decisions may be applied subject to the provisions of Article 59 which states:

The decision of the Court has no binding force except between the parties and in respect of that particular case.81

In other words, there is no stare decisis in international law. Nevertheless the ICJ does look at earlier decisions and take them into account. Value is seen in judicial consistency. But caution should be exercised when looking at a particular decision. Decisions are by majority. In the event of even division a decision may have been made by the President using a casting vote. Some dissenting judgments may be made more for political than for legal reasons. Arbitration decisions depend for their weight on the subject matter involved and the agreement between the states to submit the dispute to arbitration. The procedure of international tribunals is considered in more detail in Chapter 12.

Article 38 does not limit the judicial decisions that may be applied to international tribunals. If a municipal court’s decision is relevant it may be taken into account – the weight attached will depend on the standing of the court – eg the US Supreme Court is held in high regard, particularly in disputes on state boundaries; similarly the decisions of the English Prize Courts contributed to the growth of prize law – the law relating to vessels captured at sea during war. Municipal court decisions may also be evidence of state practice for the purpose of establishing the rules of customary international law.

3.7The teachings of the most highly qualified publicists of the various nations

Historically, writers have performed a major role in the development of international law. The significance of jurists such as Grotius, Suarez and Gentilis has already been discussed in Chapter 1. Even today states make plentiful reference to academic writings in their pleadings before the Court. Writers have played an important part in the development of international law for two main reasons, the comparative youth of a comprehensive system of international law and the absence of any legislative body. In the formative period writers helped to determine the scope and content of international law. However as the body of substantive law has increased so the influence of writers has decreased – although writers still have an important role in developing new areas of law, eg marine pollution. Who are the most qualified writers is a matter for subjective assessment – as usual in these matters death is often seen as an important qualification! It should be noted that the Court itself does not usually make reference to specific writers.

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81 Article 59 of the Statute of the ICJ.

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3.8Other possible sources

Over the last 30 years there has been increasing support for the view that Article 38 should not be understood as a comprehensive and complete list of the sources of international law. On the one hand, examples can be found from the more recent decisions of the ICJ which seem to be based on rules of law not readily falling within the triad of sources created by the statute. On the other hand it is argued that international law does not simply consist of the decisions of the ICJ. Indeed, between 1966 and 1980 the work load of the court decreased dramatically following the decision in the South West Africa case, Second Phase (1966).82 The decision was heavily criticised by the newly independent states who were already distrustful of what they perceived as a European and American bias within the Court. Rather than submit disputes to the ICJ they preferred to seek remedies through the political organs of the UN. As the work of the UN has increased it can be seen to have had a profound effect on the behaviour of states which cannot be ignored in any analysis of international law. For both these reasons, it is argued that the discussion of the sources of international law can no longer be confined to the provisions of Article 38. Support for this view can be found among the judges of the ICJ:

We cannot reasonably expect to get very far if we try to rationalise the law of today solely in the language of Article 38 of the Statute of the International Court of Justice, framed as it was in 1920. It too needs urgent rethinking and elaboration ... To use Article 38 as it stands, as we constantly do still, for the purposes of analysing and explaining the elements and categories of the law today has a strong element of absurdity.83

It is therefore necessary to consider a number of other sources of international law.

3.9Resolutions of international organisations

The exact status of resolutions of international organisations, in particular resolutions of the United Nations General Assembly, has long been an area of controversy. Nonetheless it is certainly true that the resolutions passed by the UN General Assembly have a far more significant role to play in the formation of international law than was envisaged in 1945, let alone in 1920 when Article 38 was drafted. When discussing the effect of resolutions it may be useful to consider the categories suggested by Sloan, who identifies three main categories of resolution:

• Decisions

By virtue of Article 17 of the UN Charter, the General Assembly may take decisions on budgetary and financial matters which are binding on the members. Failure to abide by budgetary decisions can ultimately lead to suspension and expulsion from membership. In addition, Article 2(5) of the Charter provides that:

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82[1966] ICJ Rep at p 6.

83Jennings, ‘The Identification of International Law’ in International Law, Teaching and Practice, Bin Cheng (ed), 1982, at p 9.

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All members shall give the United Nations every assistance in any action it takes in accordance with the present Charter, and shall refrain from giving assistance to any state against which the United Nations is taking preventive or enforcement action.

Thus arguably, resolutions that commit the UN to taking ‘action’ can be binding on member states.

• Recommendations

Article 10: The General Assembly may discuss any questions or any matters within the scope of the present Charter ... and ... may make recommendations to the members of the United Nations or to the Security Council or to both on any such questions or matters.

The essence of ‘recommendations’ is that they are non-binding. They cannot, therefore, instantly create binding rules of international law in themselves. However, recommendations can be used as evidence of state practice and thus go towards the creation of customary rules of international law.

• Declarations

Declarations are a species of General Assembly resolutions based on established practice outside the express provisions of Chapter IV of the Charter ... While the effect of declarations remains controversial, they are not recommendations and are not to be evaluated as such.84

Since 1945 the General Assembly has adopted a number of resolutions which have been termed declarations and have expressed principles of international law. Such declarations have often been adopted by unanimous vote or by consensus (ie without voting). The most comprehensive was Declaration on Principles of International Law concerning Friendly Relations and Co-operation among states (GA Resolution 2625 (XXV) (1970)). Other significant declarations have been the Declaration on the Granting of Independence to Colonial Territories and Peoples (GA Resolution 1514 (XV) (1960)); Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of Outer Space (GA Resolution 1962 (XVIII) (1963)). Certain other resolutions, although not designated as ‘declarations’ have affirmed principles of international law. One example is the resolution entitled Affirmation of the Principles of International Law Recognised by the Charter of the Nuremberg Tribunal (GA Resolution 95 (I) (1946)). It should also be noted that some ‘declarations’ by the General Assembly are not intended to express legal rights and obligations, an important example being the Universal Declaration of Human Rights (GA Resolution 217 (III)) which is expressly stated to proclaim ‘a common standard of achievement’.

It seems to be almost universally accepted today, therefore, that in certain situations UN resolutions can be used to establish binding rules of international law. Whether a particular resolution will be regarded as valid international law will depend on a number of criteria including the context in which the resolution was passed, voting behaviour and analysis of the provisions concerned. In Texaco Overseas Petroleum Co v Libya (1978),85 an arbitration which

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84Sloan, ‘General Assembly Resolutions Revisited’ (1987) 58 BYIL 93.

85(1978) 17 ILM at pp 1–37.

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arose after Libya had nationalised the property of two American oil companies, the arbitrator, Professor Dupuy, had cause to discuss the international law relating to nationalisation of foreign owned property. In particular, he referred to the General Assembly Resolution on Permanent Sovereignty over Natural Resources 1962 (GA Res 1803 (XVII)) and the Charter of Economic Rights and Duties of States, 1974 (GA Res 3281 (XXIX)). Resolution 1803 had been adopted by 87 votes to 2, with 12 abstentions. France and South Africa had voted against the resolution and the Soviet bloc, Burma, Cuba and Ghana had abstained. The resolution recognised the right to expropriate foreign owned property where it was carried out for reasons of public utility, security or national interest and where compensation is paid. Arbitrator Dupuy, who had been appointed by the President of the ICJ commented:

On the basis of the circumstances of adoption ... and by expressing an opinio juris communis, Resolution 1803 (XVII) seems to this Tribunal to reflect the state of customary law existing in this field ... The consensus by a majority of states belonging to the various representative groups indicates without the slightest doubt universal recognition of the rules therein incorporated. 86

He then turned to consider the status of the Charter of Economic Rights and Duties of States 1974. This resolution was adopted by 120 votes to 6 with 10 abstentions. The states voting against were Belgium, Denmark, the Federal Republic of Germany, Luxembourg, the UK and the USA; those abstaining were Austria, Canada, France, Ireland, Israel, Italy, Japan, the Netherlands, Norway and Spain. The provisions of the Charter were much more favourable to the developing states. Arbitrator Dupuy found that there were several factors which mitigated against recognising the Charter as a source of international law:

In the first place, Article 2 of this Charter must be analysed as a political rather than a legal declaration concerned with the ideological strategy of development and, as such, only supported by non-industrial states ... The absence of any connection between the procedures of compensation and international law and the subjection of this procedure solely to municipal law cannot be regarded by the Tribunal except as a de lege ferenda formulation, which even appears contra legem in the eyes of many developed countries.87

Since it now seems to be accepted that resolutions are capable of constituting rules of international law, debate now is focused on whether such resolutions constitute a source of law in their own right or whether they merely provide evidence of customary law or general principles of law. One resolution which has been the subject of much analysis is the Declaration on Outer Space which was passed in 1962. The main aim of the resolution was to establish a legal regime for outer space which incorporated the principles that space exploration was to be carried out for the benefit of all mankind, that ‘outer space and celestial bodies’ were not to be the subject of national appropriation, and that the use and exploration of outer space was to be carried out for peaceful purposes only. During the discussions leading to the adoption of the resolution

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86Ibid, p 30.

87Ibid, p 32.

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delegates to the General Assembly considered the legal effect of declarations in general and support was offered for the view that a declaration of legal principles, adopted unanimously could be, in effect, legally binding. A significant number of states expressed the view that the binding nature of such declarations was based on the fact that the declaration constituted state practice and also the necessary opinio juris to create a rule of custom. Such resolutions constituted, in the words of Bin Cheng, ‘instant customary law’.88 In the Nicaragua case (1986) the ICJ expressed the view that UN Resolutions could constitute opinio juris which together with evidence of state practice could constitute a rule of custom. Until the provisions of Article 38 of the Statute of the ICJ are amended it seems likely that international tribunals will continue to refer to resolutions in terms of evidence of international custom. Whether that is an accurate description of the procedure remains open to doubt.

3.10 Resolutions of regional organisations

Regional organisations, for example, the European Union, the Council of Europe, the Organisation of American States, and the Organisation for African Unity can, via their internal measures, demonstrate what they, as a regional group, consider to be the law. This is especially important in the area of human rights law, which is discussed in Chapter 15.

3.11 The International Law Commission and codification

The major difficulty with customary law is that it is diffuse and often lacks precision. In the light of this, attempts have been made to codify international law, an early example of which is provided by the Hague Conferences of 1899 and 1907 which did much to codify the laws relating to dispute settlement and the use of armed force. The codification and development of international law was a concern of the founders of the UN and that concern is reflected in Article 13(1) of the UN Charter which provides:

The General Assembly shall initiate studies and make recommendations for the purpose of:

(a) promoting international co-operation in the political field and encouraging the progressive development of international law and its codification’ (emphasis added).

In 1947, under the auspices of the UN, the International Law Commission was set up and charged with the task of progressively developing and codifying international law. The ILC is made up of 34 members from around the world who remain in office for five years each and who are appointed from lists supplied by national governments. The members of the ILC sit as individuals rather than as state representatives. Generally the Commission works on its own initiative. Draft articles are prepared and sent for comments, a conference may then be convened at which the draft articles are discussed with the aim of producing a finished convention which can then be opened for signature. Conferences can last for some time – the Third Law of the Sea Conference had

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88Bin Cheng, ‘UN Resolutions on Outer Space: Instant International Customary Law?’ (1965) 5

Indian Journal of International Law 23.

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its opening session in New York in 1973 and the Law of the Sea Convention was finally opened for signature in December 1982. Ratified conventions are clearly a source of law, while the drafts are often highly persuasive statements of present state practice in a particular area of law.

Although the ILC is the most important international body engaged in the development and codification of international law, there do exist a number of other public organisations which are involved in the same mission. Such organisations generally specialise in particular areas of law – eg the UN Commission on International Trade Law (UNCITRAL); the International Labour Organisation (ILO); the United Nations Educational, Scientific and Cultural Organisation (UNESCO). Additionally there are also some private, independent bodies engaged in the development of the law eg the International Law Association and the Institut de Droit International are two of the best known today, while the various Harvard Research drafts produced before the Second World War are still of value today.

3.12 ‘Soft law’

A recent development in the study of the sources of international law has been the claim that international law consists of norms of behaviour of varying decrees of density or force. On the one hand there are rules, usually contained in treaties, which constitute positive obligations binding states objectively. On the other hand, there are international instruments which, while not binding on states in the manner of treaty provisions, nonetheless constitute normative claims and provide standards or aspirations of behaviour. Such instruments can have an enormous impact on international relations and the behaviour of states but would not be considered law in the positivist sense. A growing body of writers has argued that both types of norms should be considered law and the distinction between the two is indicated by the terms ‘hard law’ and ‘soft law’. The concept of soft law has been used significantly in the area of environmental protection which is discussed more fully in Chapter 17.

One particular benefit of soft law is that it allows states to participate in the formulation of standards of behaviour which they may not feel, at the time of formulation, ready to implement fully. For example, the Universal Declaration of Human Rights 1948 might be considered to be soft law since it was expressed to be non-binding and instead set down aims for achievement. Since that time it can be argued that most, if not all, its provisions have transformed into rules of hard law. Another example might be the Charter of Economic Rights and Duties of States 1974 which has already been mentioned. This has undoubtedly had an effect on the behaviour of states but is certainly a long way from hardening into a binding rule of law. It is clear that within soft law there will be varying degrees of hardness. Other examples of soft law would include the Final Act of the Conference on Security and Co-operation in Europe 1975 (the Helsinki Declaration) which was expressed to be non-binding, the OECD Guidelines for Multinational Enterprises and the Gleneagles Agreement on the Sporting Boycott of South Africa. All undoubtedly have some legal effects without being creating legally binding obligations.

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3.13 Jus cogens or peremptory norms

Having discussed the distinction between hard and soft law it seems appropriate to turn to consideration of a duality of levels within hard law itself. Many municipal systems distinguish between jus cogens89 (rules or principles of public policy which cannot be derogated from by legal subjects, often referred to as ordre public) and jus dispositivum (norms which can be replaced by subjects in their private dealings). The idea that there are certain non-derogable fundamental norms in international law is not new. Even before the First World War many writers had expressed the view that treaties which contravened certain fundamental norms would be void. The doctrine of international jus cogens was heavily influenced by natural law theories. Unlike the positivists who argued that sovereign states enjoyed an almost complete freedom of contract, natural lawyers argued that states were not completely free in their treaty-making powers. They argued that there were certain fundamental principles underpinning the international community which all states were obliged to respect.

In preparing the draft articles on the Law of Treaties the ILC gave considerable thought to the doctrine of jus cogens. The ILC supported the idea that treaties conflicting with peremptory norms of international law would be void but it proposed no clear criteria by which such norms could be identified. An attempt at definition was made at the Vienna Conference and the result was seen in Article 53 of the Vienna Convention on the Law of Treaties 1969 which provides:

A treaty is void if, at the time of its conclusion, it conflicts with a peremptory norm of general international law. For the purposes of the present Convention, a peremptory norm of general international law is a norm accepted and recognised by the international community of states as a whole from which no derogation is permitted and which can be modified only by a subsequent norm of general international law having the same character.

The identical provision was included in the Vienna Convention on the Law of Treaties Between States and International Organisations or Between International Organisations 1986. The doctrine of jus cogens is further reflected in the Draft Articles on State Responsibility prepared by the ILC which propose the notion of an international crime resulting from the breach by a state of an international obligation ‘essential for the protection of fundamental interests of the international community’.90 Support for the existence of peremptory norms is also to be found in a number of judgments of the ICJ, notably in the Nicaragua case (1986) where the Court identified the prohibition on the use of force as being ‘a conspicuous example of a rule of international law having the character of jus cogens’. Other activities that have been identified as contravening jus cogens include slave trading, piracy and genocide.

Although it seems to be undisputed that international law recognises the concept of jus cogens, what is less clear is the way in which rules of jus cogens

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89See also the more detailed discussion in Chapter 4.

90(1976 – II) YBILC 73.

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may be created. Since jus cogens has the status of a higher law binding all states it should not be possible for rules of jus cogens to be created by a simple majority of states and then imposed on a political or ideological minority. During discussions at the Vienna Conference on the Law of Treaties a number of states stressed the need for universal acceptance of norms of jus cogens while the Austrian delegate argued that rules could only be regarded as having the status of jus cogens if there was ‘the substantial concurrence of states belonging to all principal legal systems’91 and the US representative argued that such a norm ‘would require, as a minimum, the absence of dissent by any important element of the international community’.92 It therefore seems that the creation of a rule of jus cogens must, at the very least, meet the requirements of the establishment of a rule of customary law. As the Russian jurist, Gennady Danilenko, has written:

As ‘higher law’ jus cogens clearly requires the application of higher standards for the ascertainment of the existence of community consensus as regards both the content and the peremptory character of the relevant rules. Only such an approach may ensure the required universality in the formation and subsequent implementation of rules designed to reflect and to protect the fundamental interests of the World Community.93

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91UNCLOT I at p 388.

92UNCLOT II at p 102.

93‘International Jus Cogens: Issues of Law-Making’ (1991) 2 EJIL at p 65.

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