Fragmenting international law through compromissory clauses? Some remarks on the decision of the ICJ in the Oil Platforms case

This article addresses the role of compromissory clauses in limiting the law applicable by the ICJ to disputes concerning the interpretation and application of treaty provisions. In the Oil Platforms case, the Court essentially tried to avoid such a problematic side-effect of compromissory clauses by relying on principles of treaty interpretation. Accordingly, customary law can be taken into account in order to interpret treaty provisions falling under the Court’s jurisdiction. However, this is only a limited mechanism aiming at balancing the principle of consent (underlying the limited jurisdiction under compromissory clauses) and the need to take other international law rules into account when applying treaty rules to the dispute before it. In particular, there are disputes governed at the same time by treaty rules and customary law, which can hardly be settled on the ground of the former only. An inquiry into the jurisprudence of the ICJ shows that the Court is also prepared to consider that disputes concerning the applicability of a treaty fall within its jurisdiction under compromissory clauses. This may be deemed an important tool at the disposal of the Court in order to avoid the fragmentation of international law under compromissory clauses. This article deals with the problem of fragmentation of international law which might be produced by compromissory clauses included in a treaty with a view to attributing to an international tribunal the competence to settle disputes concerning the interpretation of the application of the Treaty. The thesis is suggested that the limitation of the jurisdiction conferred to the tribunal only concerns the nature and content of the dispute. It does not, however, limit the law applicable to the dispute, which necessarily extends to all the rules of international law applicable in the relations among the parties. The application of the whole body of international rules for the settlement of disputes brought before a court through compromissory clauses therefore reaffirms the unity of international law and prevents international law from being fragmented into a series of self-contained treaty-regimes.