Abstract
Can international organizations (IOs) possess sovereignty like modern states? How can IOs obtain sovereignty? Can IOs supersede states as dominant political structures in the international system? Neorealists theorize that European sovereignty practice is changing the institution and rules of sovereignty, indicating that IOs as structures of political organization, particularly the European Union, can gain sovereignty through formal agreements among states and eventually supplant sovereign states. I study the emerging African sovereignty practice in relations between the African Union (AU) and the UN amidst the legitimation crisis in the UN Security Council and provide the constructivist alternative theory: IOs can attain sovereignty when dominant IOs like the UN face legitimation crises and states constituting IOs claim sovereignty. African sovereignty practice shows that sovereignty claims can occur because of noncompliance with IO legitimation rules of inclusive representation, or the alignment of values, norms, priorities, interests, or goals.