The signatories, including France, Great Britain, Australia, New Zealand, the Philippines, Pakistan, Thailand and the United States, pledged to « act to address the common danger » in the event of aggression against a signatory state. A separate protocol at SEATO designated Laos, Cambodia and « free territory under the jurisdiction of the State of Vietnam [south vietnam] » as territories also governed by the treaty provisions. The language of the treaty did not go as far as the absolute mutual defence obligations and the force structure of the NATO alliance, but provided only for consultations in the event of aggression against a signatory or a state of the protocol before joint actions were taken. This lack of agreement, which would have forced a military response combined with the aggression, significantly weakened SEATO as a military alliance. It did, however, serve as the legal basis for the U.S. engagement in southern Vietnam. SEATO expired on June 30, 1977. The Southeast Asian Collective Defence Treaty (Manila Pact) was signed on 8 September 1954 in Manila as part of the US Truman Doctrine to create bilateral and collective anti-communist defence treaties.  These treaties and agreements were to create alliances that would keep the communist powers in check (Communist China, in the case of SEATO).
 This policy was widely developed by the American diplomat and Soviet expert George F. Kennan. President Dwight D. Eisenhower`s Foreign Minister, John Foster Dulles (1953-1959), is considered the main force behind the founding of SEATO, which extended the concept of collective anti-communist defence to Southeast Asia.  Richard Nixon, then Vice-President, was a supporter of an Asian equivalent of the North Atlantic Treaty Organization (NATO) upon his return from his trip to Asia in late 1953 and NATO was the model of the new organization, with each member`s armed forces having to be coordinated to ensure the collective defence of member states.  After its founding, SEATO became militarily insignificant, with most of its member countries having contributed very little to the alliance.  While SEATO forces were conducting joint military training, they were never deployed due to internal differences. SEATO was unable to intervene in the conflicts in Laos because France and the United Kingdom refused to resort to military action.
 As a result, after 1962, the United States provided unilateral support to Laos.  Although the United States opposed it, SEATO`s participation in the Vietnam War was denied due to a lack of British and French cooperation.  After President Dwight D. Eisenhower was ordered by President Dwight D. Eisenhower to form an alliance to curb all communist aggression in the free zones of Vietnam, Laos and Cambodia or Southeast Asia, Foreign Minister John Foster Dulles reached an agreement to create a military alliance that would become the South Asian Treaty Organization (SEATO).