"Japan's role in ensuring maritime security in Southeast Asia has received some attention in recent years. Japan's primary focus on the Malacca Strait has resulted in close cooperation with the three littoral states (Singapore, Malaysia, and Indonesia), but Japan's newer initiatives for multilateral cooperation encompass a broader set of countries in East Asia. Japan particularly sees Thailand as a potential partner for maritime security cooperation. At the same time, divergence of interests and differences in institutional settings between Japan and Southeast Asian countries pose some obstacles to closer cooperation. This article will assess Japan's maritime security cooperation with Southeast Asia and explore implications for U.S. policy."--Abstract from DTIC.