The treaty was a product of U.S. cold war policy. The United States had washed its hands of China’s civil war in 1948, but had become concerned about communist expansion when Communist North Korea attacked proWestern South Korea in 1950. The United States then sent the Seventh Fleet to patrol the waters in Taiwan Strait.
In September 1954 the PRC attacked the ROC. The terms of the treaty committed the U.S. government to deploy land, sea, and air forces in and around Taiwan as required for its defense. The treaty also stipulated that the ROC and the United States would aid each other to increase their capacity to resist an armed attack or communist subversive activities directed against either country’s territorial integrity. Furthermore, both sides agreed to maintain peace and security in the region and refrain from the use of force in any manner inconsistent with their obligations to the United Nations.
Following the 1954 crisis with the PRC, the United States became concerned that the nationalist government of Taiwan might deploy force against the mainland. This could possibly involve American troops despite the treaty’s defensive nature. United States Secretary of State John Foster Dulles met with ROC president Chiang Kaishek to urge against attacking the PRC.
An incident occurred in 1958 when the PRC shot down two Nationalist F-84s on patrol. The PRC also renewed attacks on the offshore islands in midsummer 1958, testing the commitment of the United States to the treaty. In response, the United States deployed an aircraft carrier battle group to the region that included combat aircraft and transports. Nationalist forces were escorted safely by their ships to supply their offshore islands.
Both the United States and the Soviet Union urged a peaceful solution. Throughout the 1950s–60s the United States remained sympathetic to the cause of the ROC but also acted to restrain the ROC from acts that might provoke the PRC.
Beginning in 1971 the United States began to negotiate with the PRC. In 1972 President Richard Nixon visited China. The visit culminated in the Shanghai Communiqué in which China declared that Taiwan was a part of China and that differences should be resolved peacefully.
In 1978 President Jimmy Carter established formal diplomatic relations with the PRC, effective in 1979, thereby severing relations with the ROC and ending the U.S.-ROC Mutual Defense Treaty. A Taiwan Relations Act enacted by the U.S. Senate in 1979 authorized non-official relations with the ROC that also provided for the U.S. sale of weapons to the ROC.