Why have ASEAN member states declared and why do they continue to declare their intention to enhance cooperation and devise projects when implementation lags behind their rhetoric? Why do they rhetorically commit themselves to cooperation, when they continue to stick to self-interested policies to the detriment of ASEAN's collective interest? And given these diverging practices, how likely is it that the objective of a more legalized and binding cooperation associated with the recently ratified ASEAN Charter is being implemented? This article draws attention to ASEAN's hybrid or dual character of international cooperation, consisting of the emulation of the European integration project and the persistence of deeper cultural strata of Southeast Asia's cooperation project that determine the limits of cooperation: Southeast Asia's social structure and political culture that have not produced those mechanisms that might facilitate international cooperation. If our explanation is correct that cooperation within ASEAN comes about as a simultaneous process of emulation and established cultural practices, we expect change only under specified conditions. Based on our argument and the theoretical literature on normative change, we identify and discuss in greater detail three potential outcomes of change: inertia, localization and transformation. The three modes make different predictions concerning change within ASEAN. Based on an analysis of the two major shocks with which ASEAN has had to contend in the last two decades,