East Asian economic integration has rapidly advanced through several mechanisms: the economic dialogue in APEC and ASEAN+3, financial cooperation via the Chiang Mai Initiative Multilateralization (CMIM), and infrastructure investment through the Asian Infrastructure Investment Bank (AIIB) and portals for implementing China’s One Belt One Road initiative (OBOR). Most recently, the Trans Pacific Partnership joined by 12 Asian Pacific countries has been signed, serving as the cornerstone of the U.S. “pivot to Asia.” Why should the United States care so much about the degree of economic integration between East Asian nations – the nations encompassing Korea and Japan in the north, China in the middle, and ASEAN in the south? Like “motherhood and apple pie,” economic integration seems like a good thing. But to put the question starkly, does economic integration among the 15 countries of East Asia have any greater importance for the United States than economic integration among the 54 countries of sub-Saharan Africa? The answer is a resounding “yes,” both for security and economic reasons. Our paper addresses in turn the security and economic aspects of East Asian economic integration from an American perspective.