The Role of General Assembly Resolutions in the Identification of Customary International Law and the Chagos Archipelago Advisory Opinion

This article analyses how the Chagos Archipelago Advisory Opinion (2019) has contributed to the determination of the role of General Assembly resolutions in the identification of customary norms. By exposing, firstly, the many theories on the weight of these international organisations’ instruments and, secondly, which of these conclusions are considered customary (by the International Law Commission’s work on Identification of Customary Law and by the International Court of Justice’s jurisprudence); it defends that the Chagos advisory opinion has innovated in three main points. Firstly, the resolutions were not subsidiary evidence, but rather the central point of analysis for establishing the existence and scope of the right to self-determination. Secondly, the Court has offered more elements to be observed in these instruments than it ever did. Thirdly, although maintaining the focus on State practice, the Court acknowledged the role of the General Assembly, as one collective organ, on decolonisation as relevant.