Southeast Asia Treaty Organization (SEATO)
Southeast Asia Treaty Organization (SEATO), defense treaty signed by Australia, France, Great Britain, New Zealand, Pakistan, the Philippines, Thailand, and United States after France withdrew from Indochina in 1954. Headquarters were at Bangkok, Thailand. Although there were no standing forces, its aim was to prevent Communist expansion. The treaty was invoked by the United States in the Vietnam War (1964–73). Pakistan withdrew in 1972. SEATO dissolved in 1977.