Shared Obligations and the Responsibility of an International Organization and Its Member States: The Case of EU Mixed Agreements

Discussions on the allocation of international responsibility between an international organization and its member states do not comprehensively engage with the role of obligations in assigning responsibility to the organization and/or its members. The present article sets out what will be termed an obligations-based approach to the allocation of international responsibility by exploring the phenomenon of sharing international obligations by an international organization and its members, as well as the implications thereof for their responsibility under international law. It will do so by focusing on the practice of concluding mixed agreements by the EU and its member states, which commonly results in overlapping obligations for the organization and its members. It is ultimately argued that a distinction should be made between two types of shared obligations in mixed agreements in order to untangle who can be held responsible in case of a breach: the EU, the member state(s), or both.