Using institution-building theory from the school of neoliberalism, the paper examines the role of leadership and institutional bargaining in moving the "10+3" regional cooperation framework forward. The core argument developed here is that close cooperation between Japan and China is key to the future of "10+3", and ASEAN states and South Korea should utilize the "10+3" platform for bringing Japan and China together. Finally, some ASEAN states’ fear that a more integrated East Asia will mean the withdrawal of U.S. presence in the region is very remote.