Southeast Asia Treaty Organization (SEATO), alliance of nations to provide defense and economic cooperation in Southeast Asia and the South Pacific area. The alliance was founded on September 8, 1954, less than two months after agreements reached at the Geneva Conference had paved the way for the French withdrawal from Indochina. The founding members of SEATO were Australia, France, the United Kingdom, New Zealand, Pakistan, the Philippines, Thailand, and the United States. Like the North Atlantic Treaty Organization (NATO), the Southeast Asian alliance was intended to prevent the spread of communism; but unlike the NATO pact, the SEATO agreement did not obligate one member to assist another against a military threat. Although SEATO sanctioned the U.S. military effort in Vietnam, and although several SEATO members sent troops to fight there, SEATO itself played no direct role in the war. France ceased active participation in SEATO in 1967; Pakistan officially withdrew in 1972. With the U.S. withdrawal from Vietnam and the Communist victories throughout Indochina in 1975, SEATO became an anachronism. By mutual consent, the alliance disbanded on June 30, 1977.