The International Court of Justice and Territorial Disputes: an Updated Systematization

Abstract

Over the course of the past 75 years, the International Court of Justice (ICJ) has adjudicated a total of 17 territorial disputes, building a considerable body of case law along the way. While the Court has shed light on many legal issues concerning territorial sovereignty over the years, it has never clarified its approach to territorial disputes. Bridging the gap between a 2004 analysis by Brian Sumner, who identified a three-tiered hierarchical decision rule, and modern territorial doctrine, this study aims to provide an updated attempt at systematization of the Court’s approach in its case law concerning territorial disputes. Refining Sumner’s hierarchical decision rule, the findings – while overall congruent with the basic hierarchy identified in his work – suggest that the Court’s approach revolves around a hierarchy of three tiers of territorial titles (understood broadly as sources of the right to territory), namely, legal instruments, State succession and intangibility of boundaries, and independent effectivités. Equity infra legem is used as a last resort tool for interpretation of these titles, where they themselves yield no clear result. Another source of the right to territory, unilateral conduct constituting acquiescence and/or estoppel, is relied on outside of this hierarchy, often to support a decision based on another title. A review of the entirety of the Court’s case law reveals a relatively consistent yet multi-layered approach to territorial disputes.