International Law 2005 Q1

 Elaborate on how a rule of customary international law is formed and the nature of its principal elements, by reference to decided cases.

Sources of international law consists of primary sources (formal sources) and secondary sources (material sources). Primary sources are sources that create the rules of international law which could emerge from international treaties, customary international and general principles of law recognized by the civilized nations. Secondary sources are judicial decision, writings of jurists and resolution of United Nations General Assembly and reports made by international law commission.

Customary International Law is a law that evolved through the practice or customs of states. Generally speaking customary international law is the foundation stone of modern law of nations. Even though custom is the major source of international law and it is now gradually being replaced by treaties yet a great deal of the law governing the states today, still comes from this source. Thus, one can strongly affirm that international law has been rooted in customary law.

Article 38(1)(b) of the Statute of International Court (ICJ) expressly provided that international custom as evidence of a general practice accepted as law. The provision was vividly elucidated in the case of North Continental Shelf where it was held that the state practice must be general, consistent with such rule and should amount to a settle practice in addition supported by opinion juris sive necessitatus. Thus, in order to form a customary international law or for any custom to be crystallized into a customary law, the Court will have to evaluate a state practice and the opinion juris. These two are sometimes referred as objective and subjective elements of customary law.

What is meant by state practice? State practice is a material fact that refer to what the state actually do. It is not limited to actual activity facts and omissions of a state but a practice which are embodied in law of official legislation of the state, judicial decision and official manual. Statement made by government officials and the spokesman to the international conference or press in respect of situations or disputes also may indicate of state practice. Documentary records of ‘practice’ such as the Repertory of Practice of UN Organs is also of considerable practical importance. However, different type of activity carries different type of weight. Even local custom also may form a customary law if the practice is developed between few states and they recognize it as binding upon them (Asylum Case – Columbia v Peru). Be that as it may, it is pertinent to note that a contrary state practice will be presumed to be action in breach of the rule (Nicaragua v USA).

In order to establish state practice one must look at the repetition, duration and consistency of the said practice.

How many examples of state practice or repetition are required? In the case of North Sea Continental, the Court said that it cannot mathematically or uniformly be decided. Each fact requires to be evaluated relatively according to the different occasions and circumstances. Even a single act without subsequent repetition such as outer space program can be regarded as custom as long the states regarded the new practice as binding. 

There is no guideline on the duration of state practice either. The ICJ never set a guidelines on the time required for state practice to mature into customary law because the creation of customary law is inherently fluid. Further, in North Sea Continental Shelf Cases it was held that the length of time needed will vary from subject to subject and a brief period of time is not a bar to the formation of customary law but nevertheless a practice in short period of time can suffice if there is widespread and representative participations. In Right of Passage Over Indian Territory, a case concerning a right to transit from the Portuguese colony of Goa (on the coast of India) to little Portuguese-controlled enclaves in the interior of India, between Portuguese and Indian governments. The court held that there had been a custom existed for many century between its predecessors ie British and Maratha rulers thus Portuguese right of passage binding upon India.

The state practice also must be reasonably consistent. It must, in the words of the Permanent Court in the Lotus Case, be ‘constant and uniform’. There is no need be total consistency, for it is clear that this criterion is satisfied if there is substantial, rather than complete consistency in the practice of states. It is also clear from the Anglo-Norwegian Fisheries Case that the degree of consistency required may vary according to the subject matter of the rule in dispute. In The Asylum Case, the Peruvian military leader took refuge in the Colombian Embassy in Lima after leading an unsuccessful coup attempt. The Peru government turned down the Colombian government’s request for safe passage out of the embassy, out of the country and to the asylum state. The issue before the ICJ was whether a custom exists then with regard to the political asylum. The Court held that the facts….disclose so much of uncertainty and contradictions, so much fluctuations and discrepancy in the exercise of political asylum in the ……it is not possible to discern in all this any constant and uniform usage, accepted as law… . The court held that the Columbian Government failed to prove the existence of such custom.  

Mere general, uniform and consistent state practice are not sufficient for the formation of customary law. The state must also recognize such practice as binding upon them as law.

In the Lotus Case, the PCIJ emphasized that opinio juris was an essential element in the formation of customary law and the same was reaffirmed in the North Sea Continental Shelf Cases and has been accepted ever since. Opinio juris attempts to ascertain whether a practice is observed out of a sense of legal obligation or necessity or rather merely out of courtesy, neighborliness or expediency. On this point, a majority of the Court in the North Sea Continental Shelf Case said that ‘the frequency or even habitual character’ of a practice is not enough to establish opinio juris.

Opinio Juris is usually defined as conviction felt by states that certain form of conduct is required/recognized by international law. In Lotus Case it was held as a matter of inference from all circumstances, not merely the detailed acts which constitute the material element of the alleged customary rule.

How opinio juris may be proved was outlined in North Sea Continental Shelf. The Court went on to state that a state practice must be a settle practice and it must be done in such a way that the practice rendered obligatory upon the state by the existence of rule of law. The need for such a believe is a need for a subjective element to implicit in the very notion of opinion juris. The states must feel that they are conforming to what amount to legal obligation.

Be that as it may, Judge Tanaka in his dissenting judgment expressed that the opinion juris as something very difficult to achieve. He was of the view that it is extremely difficult to get evidence of its existence in a case. Opinio juris being of a psychological in nature, cannot be ascertained easily, particularly when diverse legislative and executive organs of a government participate in the process of decision making in respect state’s act. There is no other way then to ascertain OJ, from the fact of external existence of certain custom/practice and its necessity felt in international community, rather then to seek evidence as to the subjective motive of each examples of state practice, something which is impossible of achievement.

Judge Sorensen in his dissenting judgment in the case of North Continental held that the practice of state is sufficient evidence of the existence of any necessary opinion juris.

Treaty can also form a new customary law based on the provisions in it. The Court will refer to certain conditions which would have to be satisfied before declaring certain practice based on the provision of treaty had crystallized into customary law. A treaty rule may relate to customary law in one of three ways : -

a)    It may be declaratory of a rule of customary international law;

b)    It may crystallized a rule of customary international law, which means widespread and representative participation in the treaty; and

c)    It may serve to generate a rule of customary international law in the future by subsequent practice of state.

In the case of Delimitation of Maritime Boundary in the Gulf Area 1984, the ICJ said that general convention in which principle and rules of general principles can be identified, must be seen against the background of the subsequent CIL and interpreted in its light. 1958 Convention regarding continental shelf, the ICJ – the fact that there is 1958 Convention which applies to continental delimitation in the case does not mean Art. 6 in the convention can be interpreted without reference to subsequent rule of customary international law on the subject matter.

Thus, as elaborated above are the ways how customary international law is formed and the nature of its principle elements according to the decided cases.