After some false starts in Southeast Asian cooperation in 1963, ASEAN was formed in 1967 at the time of the cold war. It was composed of the non-communist parts of SEA, namely, Indonesia, Malaysia, the Philippines, Singapore and Thailand. Initially, it aimed mainly at economic cooperation and diplomatic interactions. The prevalent arrangements in security/military coopera6on in the Asia-Pacific was affected by bipolarity of the cold war. Essentially, the arrangements were bilateral alliances and military partnerships between an Asian state and an extra regional major power in each camp. For example, the bilateral defence treaty between US and Japan, US and the Philippines, US and South Korea, US and Thailand, US and Taiwan and Soviet Union and Vietnam. The only regional/mul6lateral security cooperation was SEATO (1954 to 1977) headed by the US and the consultative. Five-Power Defence Arrangements headed by the UK starting from 1971. In addition, there were some bilateral or trilateral border security agreements and defence links among selected ASEAN states. There was no region-wide security cooperation in the Asia-Pacific in the cold war period. It remains to be noted that for Southeast Asian security in the cold war, ASEAN took an ac6ve role in resolving conflicts. Basic principles and approaches in security cooperation were developed; these included notably the ASEAN way and the Treaty of Amity and Cooperation in Southeast Asia.