Southeast Asia Treaty Organization - Membership

Membership

Despite its name, SEATO mostly included countries located outside of the region but with an interest either in the region or the organization itself. They are: Australia, France, New Zealand, Pakistan (including East Pakistan, now Bangladesh), the Philippines, Thailand, the United Kingdom, and the United States.

The Philippines and Thailand were the only Southeast Asia countries that actually participated in the organization. Both shared a close tie with the United States, particularly the Philippines, and both were facing with incipient communist insurgency against their own governments . Thailand became a member upon the discovery of the newly found “Thai Autonomous Region” in Yunnan Province (South China) - apparently feeling threatened by potential Chinese communist subversion on its land. Other SEA countries like Burma and Indonesia were far more minded with domestic internal stability rather than concern of communism threat, hence rejected joining . Malaya (including Singapore) also chose to not participate formally, though was kept updated with key developments due to its close relationship with the United Kingdom . The rest of Southeast Asia countries: Vietnam, Cambodia and Laos were prevented from taking part in any international military alliance as a result of the Geneva Agreements signed July 20th of the same year concluding the end of the First Indochina War . However, with the lingering threat coming from communist North Vietnam and the possibility of the domino theory with Indochina turning into a communist frontier, SEATO got these countries under its protection - an act that would be considered to be one of the main justifications for the U.S. involvement in the Vietnam War.. Cambodia, however rejected the protection in 1956.

The majority of SEATO members however are not geographically presented in Southeast Asia region. To Australia and New Zealand, SEATO was seen as a more satisfying organization than ANZUS – a collective defense organization with the U.S. . Great Britain and France joined due partly to the long maintained colonies in the region, partly to the concern over the development in Indochina. Pakistan, however, was simply interested for joining over the appeal of potential support for its long struggle against India. Last but not least, the U.S.A. upon perceiving Southeast Asia to be a pivotal frontier of the Cold War geopolitics saw the establishment of SEATO as essential to its Cold War containment policy.

All in all, the membership reflected a mid-1950s combination of anti-communist Western nations and such nations in Southeast Asia. The United Kingdom, France and the United States, the latter of which joined after the U.S. Senate ratified the treaty by a 82–1 vote, represented the strongest Western powers. Canada also considered joining, but decided against it in order to concentrate on its NATO responsibilities.