Chapter 2 explores the ILC framework of international responsibility. The aim of the analysis is to identity rules which govern the allocation of international responsibility in a multi-layered structure where sovereignty is shared between different subjects of international law. This study argues that the purpose of both the ARIO and the ARSIWA is to determine whether a subject of international law is internationally responsible. If the question of responsibility arises in the context of a multi-layered structure, such as that of the EU, additional questions arise. The allocation of international responsibility within an international body falls outside the scope of the ARIO framework. Instead, this book suggests looking for guidance in the rules of organisation and the international dispute-settlement practice in which these rules operate.