Emerging East Asian economies have seen their share of world exports more than triple during the past quarter-century, and intraregional trade has driven this growth. Broad measures of development in East Asia have improved at the same headlong pace. Why push further integration now? Two economic events of historic proportions provide the context: strategic thinking of development in the region following the East Asian financial crisis of 1997-98 and the accession of China to the World Trade Organization. Policymakers interested in a stable, prosperous region are concerned by mildly rising...