This chapter examines Third World regional organizations’ discursive foundations, focusing on macronationalism as a movement and discourse, and tracing the development of the OAS, the OAU, and ASEAN. Decolonization produced sovereignty-sensitive states. It also, in some cases, produced regional international societies founded on macronational ideologies, like pan-Americanism and pan-Africanism. And because macronationalism appeals to values and solidarities that transcend the nation state, it holds the potential to challenge strict sovereignty norms. In Latin America and Africa, the establishment of regional organizations in some ways culminated pan-American and pan-African movements, but the formation of ASEAN did not culminate pan-Asianism – the latter had long lost favor in the wider region due to its cooptation by imperial Japan. ASEAN’s discursive foundations served more to reinforce strict sovereignty norms – in the long run – than to create openings for contestation of them. Non-interference did not have to compete with transnational pan-Asian discourses or liberal ideas about human rights and democracy that were more prominent in the African and Latin American cases.