The international relations of Southeast Asia has traditionally been determined by external powers. During the Cold War until the conclusion of the Second Indochina War in 1975, the United States had overwhelming influence on the ASEAN states. Between 1975 and 1989, ASEAN achieved greater accommodation with China to address Thai security concerns. Since 1989, ASEAN has been relatively free of external power entanglements. Preliminary evidence from the past indicates a generally favourable appraisal of the United States and Japan and a more cautious attitude towards China. ASEAN's new latitude in managing its own affairs is complicated by its membership expansion and internal disagreements. However, ASEAN's manifest desire is that the major external powers will provide a favourable regional environment for peace and development. Introduction External powers have traditionally determined the contours and context of international relations in Southeast Asia. The earliest influences, until the sixteenth century, derived from China and India. However, beginning from the sixteenth century and especially after the eighteenth century, European colonial powers began to actively extend their empires into Southeast Asia. The only country that retained its sovereign status in the region was Thailand. [1] European influence on Southeast Asian international relations evaporated rapidly after World War II and the Japanese Occupation of the region from 1942 to 1945. The pressures of domestic independence movements, military engagements, and the crystallization of states as the primary political units in world affairs led to the breakup of colonial empires. The process began with the Philippines in 1946 as part of the first wave of decolonization and ended with the Geneva Accords of 1954 which partitioned Vietnam into two halves. [2] The second wave brought independence to the Malay Archipelago -- the Federation of Malaya in 1957, which was expanded to the Federation of Malaysia in 1963. Singapore separated from Malaysia in 1965, and Brunei was the last state to become independent in 1984. The process of decolonization dovetailed with the onset of the Cold War. Accordingly, Southeast Asia operated as a sub-system of broader global structural arrangements for most of the period from the 1960s to the 1980s. [3] Given the overwhelming influence of the United States, the Soviet Union, and China during this period, the region's destiny was understandably intertwined with and determined by these and, to some extent, other extra-regional powers. In this regard, both Southeast Asia as a region and the Association of Southeast Asian Nations (ASEAN) as an organization have been relatively free of overwhelming external influences for only the last decade. This article examines the relationship between ASEAN and three major extra-regional powers -- China, Japan, and the United States. Two caveats are necessary at the outset. The first of these is that whereas Southeast Asia is a region comprising ten sovereign states, ASEAN is only an organization in which all ten states have collective membership. In this regard, the region is, to all intents and purposes, much larger, both philosophically and in terms of its major attributes, than ASEAN. Accordingly, the two units should not be used interchangeably. In this regard, ASEAN is but one of many international fora available to regional countries to create and utilize opportunities, ensure greater collaboration and calibration of policies, achieve and enhance familiarity and accommodation, and serve as a vehicle for extra-regional representations. The second caveat pertains to the treatment of ASEAN as a unitary corporate entity. It should be noted that insofar as collaboration and co-ordination is concerned, there are often significant differences or disagreements between the policy positions of individual member countries. Collective pronouncements are therefore often premised on the lowest common denominator principle, given ASEAN's consensual decision-making model. …