A Few Reflections about uti possidetis iuris and Self-Determination between the Twentieth and the Twenty-First Centuries

The Advisory Opinion of the ICJ on Chagos, and the ongoing conflict concerning – inter alia – the international borders resulting from uti possidetis beyond decolonization in some areas of the former Soviet Union, suggest that a clarification of the relationship between uti possidetis and the right of self-determination of peoples is in order. After summarizing the effects of the Chagos Advisory Opinion on the relations between territorial (and maritime) divisions drawn in colonial times and peoples’ self-determination, the author clarifies why uti possidetis is a delimitation principle that can be used outside the context of decolonization, provided the conditions for its applicability are met, and how it can impact the right to self-determination. In light of these reflections, some concluding remarks on the relationship between uti possidetis and the right of self-determination of peoples in contemporary international law are made.