中美共同防禦條約
Previously, the United States recognized the Republic of China as the sole legitimate government of China despite the loss of the territory during the Chinese Civil War. In 1954, the US and the ROC on Taiwan (Formosa) signed the Sino-American Mutual Defense Treaty, which essentially prevented the People's Liberation Army from taking over the island of Taiwan. During the Cold War, the treaty prolonged and assisted the Republic of China in maintaining legitimacy as the sole government of the whole of mainland China until the early 1970s and also helped US policymakers to shape the policy of containment in East Asia together with South Korea and Japan against the spread of communism. In 1980, the treaty was abrogated after the US normalized relations with the PRC.