Abstract：Most Asian countries were reluctant to commit to regional institutions and felt more comfortable with cooperation in decentralized and non-institutionalized settings, or a soft approach toward regionalism. In explaining the persistence of soft regionalism, realist scholars often cite the sheer size and diversity in the form of historical legacies, economic and ideological differences, and ambiguous geographical boundaries as particularly daunting obstacle to any formal efforts to institutionalize regional cooperation in Asia–Pacific. In contrast, liberal scholars have used integration theory to argue that, as a result of political spillover of economic interdependence, Asian regionalism is inevitable and will resemble Europe’s model of regional integration. This paper argues that each of the above two explanations captures only part of the truth. On the one hand, although the size and diversity of regions do not prevent regionalism from occurring, they are important variables to influence negotiations of regional institution-building efforts. On the other hand, while economic interdependence indeed facilitates regional cooperation, it does not dictate the organizational choice of regional cooperation. Going beyond economic variables, this paper examines the changing political environment that created new incentives for building regional institution in the Asia–Pacific after the end of the Cold War and how sheer size and diversity of the region has produced a unique Asian style of regionalism, exemplified in the ASEAN and APEC Way of Institution-building.

Keywords：Regionalism, Asia–Pacific, Economic interdependence, ASEAN ,APEC ,Regional institution building

（Suisheng Zhao：The Charhar Institute, China,“Journal of Global Policy and Governance”, 05 September, 2013）