The Background and the Puzzle
Following its open-door reforms programme (widely known as doi moi) introduced in 1986, Vietnam began to develop all-sided relations with the Association of Southeast Asian Nations (ASEAN). The process of Vietnam-ASEAN rapprochement was marked by Vietnam signing the Treaty of Amity and Co-operation in 1991 and its membership of the organization in 1995 -- the only formal international treaty and organization that the country has entered since the end of the Cold War. Myanmar and Laos joined ASEAN in 1997 and Cambodia in 1999. It has been widely acknowledged that after East Timor gains full independence, it too will seek membership in ASEAN. The mode of ASEAN co-operation now covers the entirety of the Southeast Asian region. These developments were contrasted with what had happened earlier in Southeast Asia: in general, the relations between Vietnam and ASEAN had reflected the patterns of amity and enmity among regional states along the ideological divide during the Cold War and especially during the Vietnam War. Furthermore, when Vietnam sent troops to Cambodia in 1979, relations between Vietnam and ASEAN became more hostile. For more than two decades, the existence of ASEAN and the Indochinese group, consisting of Vietnam, Laos, and Cambodia, effectively divided Southeast Asia into two opposing camps.
Why did Vietnam decide to join ASEAN in 1995? Why did it attach such significance to peace and co-operation in Southeast Asia for the cause of national political and economic development? What had prevented Vietnam from doing so earlier? For the last fifteen years, starting from 1986 when the reforms in Vietnam officially began, considerable efforts (many of which will be reviewed below) have been made to explain the shift towards a co-operative posture by Vietnam with regard to the Southeast Asian course of co-operation --defined as the process of policy co-ordination in which goal-oriented actors adjust their behaviour to the actual or anticipated preferences of others. (1) Yet, while more adequate and satisfactory answers to these questions have not yet been found, new developments in Vietnam and the rest of Southeast Asia, not to mention those in the rest of the world, keep adding new dimensions to the study of Vietnam's foreign relations. A search for a more plausible theoretical framework with a higher level of abstraction, therefore, is required.
The end of the Cold War also changed the context of Vietnam's foreign relations with big powers. The Soviet Union collapsed in 1991, effectively terminating the Soviet-Vietnamese alliance officially established in 1978 with the conclusion of the Treaty of Friendship and Cooperation. Relations between Vietnam and China were normalized in 1991, with the two states agreeing not to return to the type of alliance that had existed in the past and which was broken with the border war between the two countries in 1979. Besides, although relations between Vietnam and the United States started to improve in the early 1990s, and the two countries normalized diplomatic and trade relations in 1995 and 2001 respectively, ideological differences and the legacy of the Vietnam War still complicate this bilateral relationship. The impacts to Vietnam's foreign relations in Southeast Asia have been curious. On the one hand, Vietnam no longer enjoys alliance-type relations with any big power. On the other hand, it enjoys greater freedom in the conduct of foreign policy. The absence of constraints imposed by big power confrontation on smaller states and the relaxation of ideological constraints in world politics following the end of the Cold War suggest that Vietnam and other Southeast Asian states can be freer to follow their nationalist agenda. The region, therefore, would be "ripe for rivalry" (2) because the regional states have traditional suspicions about, and territorial disputes with, each other; moreover, many of them possess more military capabilities as a consequence of several decades of steady economic growth. …