Having been directed by President Dwight D. Eisenhower to put together an alliance to contain any communist aggression in the free territories of Vietnam, Laos, and Cambodia, or Southeast Asia in general, Secretary of State John Foster Dulles forges an agreement establishing a military alliance that becomes the Southeast Asia Treaty Organization (SEATO).
Signatories, including France, Great Britain, Australia, New Zealand, the Philippines, Pakistan, Thailand, and the United States, pledged themselves to “act to meet the common danger” in the event of aggression against any signatory state. A separate protocol to SEATO designated Laos, Cambodia, and “the free territory under the jurisdiction of the State of Vietnam [South Vietnam]” as also being areas subject to the provisions of the treaty. The language of the treaty did not go as far as the absolute mutual defense commitments and force structure of the NATO alliance, instead providing only for consultations in case of aggression against a signatory or protocol state before any combined actions were initiated. This lack of an agreement that would have compelled a combined military response to aggression significantly weakened SEATO as a military alliance. It was, however, used as legal basis for U.S. involvement in South Vietnam. SEATO expired on June 30, 1977.