Article 38 of the statute of the International Court of Justice(ICJ).

 

Custom can be divided into local custom and general custom. Although they involve many states, and contributes a larger part to the making of international law,  international customs are perhaps less important in this particular discussion than local custom, as considered by the court in the ‘Right to Passage’ case. Although no specific time duration is required to validate a custom, as in Northern Sea case, there is requirement for substantial uniformity of practice (Asylum Case), where the custom must be proved to be established in such a manner that it had become binding on the other party. Whilst not necessary in the case of a local custom as a source of law, generality of the practice is important in respect of international custom (Anglo-Norwegian Fisheries Case). Silence is generally held to be acquiescence to custom as law, but acceptance by the relevant states is necessary factor for consideration. Opinion juris, is a (the most debated) requirement that there is a consideration on the part of the relevant states holding the practice to be law, a belief that the custom is legally binding. Although there are two distinct interpretations to this requirement; a non presumption of the requirement as taken in Lotus, and Northern Seas by the majority, and that there should be a presumption of the requirement, such as taken by Judge Lachs and Tanaken in their dissenting judgements of the Right to Passage case. Thus, recognised by the ICJ in Columbia v. Peru, the principle adopted by the court was that local custom may increase or derogate from general customary international law. In effect, this is what creates a hierarchy of the sources of law.

When a treaty comes into force, it will overrides customary law as between the parties to the treaty (Wimbledon Case).  States make treaties because they regard the relevant rules of customary law is inadequate. However, treaties can come to an end through desuetude, which often takes the form of the appearance of a new rule of customary law, conflicting with the treaty.  The only difference between treaties and custom is one of type, treaties representing an express agreement and custom characterising an implied agreement. .

General principles is the third source of law, where principles that are common to all or most national systems of law is used to fill the holes in international law. Today, it has come to regulate certain contracts made by individuals or companies with states or international organizations such as, contracts of employment in international organizations. Treaties and customary law contain limited rules applicable to such topics and the gap has been filled by recourse to general principles of commercial and administrative law, borrowed from national legal systems. However, it is important to note that treaties and custom prevail over general principles of law in the event of conflict.

Nevertheless, there may be other hierarchies based on other grounds as in Hulsroj article, who thinks general principles of law is a better source of law than customs. Although his view is very much based on the face that there must be no non liquets, and appears to be biased in such a way, it does highlight the issue that Article 38 must be interpreted, to have an order of sources of law as shown by the courts in the Right of Passage case.

Judicial and academic writings are secondary to the other three sources listed above. Depending on the quality of the reasoning which the judge or writer portrays, judicial decisions usually outweighs academic writings. Besides that, the court is also directed to ‘apply’ the teachings of the most highly qualified publicist of the various nations.  

In conclusion, whilst there is an implied hierarchy of sources in Article 38, it may be that such a hierarchy is diminished by the ability of the sources to co-exist and to overlap. (Nicaragua) (Northern Sea) As put forward by Rosalyn Higgins, ‘sources of international law are not compartmentalized, but do indeed overlap’. Thus, there should be a hierarchy of sources according to their probable reliability in yielding a truly universal rule of international law.

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Bibliography

• Antonio Cassese, International Law in a Divided World (Oxford: Clarendon, 1986).

• E. Olufemi: The Nature of Subjective Element in Customary International Law ICLQ vol. 44 (1995) 501 – 520

• Fitzmaurice, "Expression of Consent to be Bound by a Treaty as Developed in Certain Environmental Treaties" in Klabbers and Lefeber, eds., Essays on the Law of Treaties (1998)

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• Ian Brownlie, Principles of Public International Law, 4th ed. (Oxford: Clarendon, 1990).

• Lukashuk, "The Principle Pacta Sunt Servanda and the nature of Obligation under International Law" (1989) 83 AJIL 513-518

• Malcolm N. Shaw, International Law, 4th ed. (Cambridge: Grotius Publications, 1997).

• Peter Malanczuk, Modern Introduction to International Law, Akehurst’s, 7th rev’d ed. (London: Routledge, 1997). Rosalyn Higgins, Problems and Process: International Law and How We Use It (Oxford: Clarendon, 1994).

• P.K. Menon, An Introduction to the Law of Treaties (Barbados: UWI / USAID Caribbean Justice Improvement Project, 1992)

• Rosalyn Higgins, Problems and Process: International Law and How We Use It (Oxford: Clarendon, 1994)

• Sir Robert Jennings and Sir Arthur Watts, eds., Oppenheim’s International Law, 9th ed. (London: Longman, 1996).

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