This paper looks back on the evolution of institutional frameworks for economic integration in East Asia, which accelerated after the Asian financial crisis, analyzes its dynamics and future prospects, and identifies Japan's roles in the process that are consistent with the institutional transformation of its economy and society as well as the fundamental interests the United States have in Asian integration and constructive roles it can play in the process. In Section I, it analyzes the forces influencing the development and performance of various regional frameworks. In Section II, the paper assesses the prospects for Asian economic integration in light of these forces as well as perceived obstacles. Section III examines the link between Japan's policy efforts to overcome economic and political challenges, and the development of various institutional frameworks for East Asian economic integration. In Section IV, this paper presents positive implications for the U. S. policy for Asia.