The Use of Precedent and External Case Law by the International Court of Justice and the International Tribunal for the Law of the Sea

Abstract

Judicial decisions are explicitly mentioned in Article 38 of the Statute of the International Court of Justice (ICJ) as “a subsidiary means for the determination of rules of law”. Doctrine and judicial decisions are then usually categorised as subsidiary or material sources. Despite the absence of any rule on binding precedent in international law generally, references to previous cases of both the Permanent Court of International Justice and the ICJ, and increasingly also case law from other courts and tribunals, in the decisions of the ICJ and the International Tribunal for the Law of the Sea (ITLOS) are a widespread phenomenon. This article aims at mapping out and critically evaluating the practice of both the ICJ and ITLOS in using and relying on their own previous case law or external case law of other international courts and tribunals. I will first identify the conventional principles applicable to judicial and arbitral decisions as “sources” of international law. I will next map the practice of the ICJ by investigating the ways in which the ICJ has used its previous decisions, as well as those of its predecessor, and that of other international courts and tribunals. Finally, I will discuss and analyse the practice of the ITLOS.