Most people assume that after World War II the U.S. government made a mistake not fighting in China against the communists. But the U.S. government's main goal was to try to break up the Sino-Soviet alliance. A secret CIA report from December 1948 even advised letting the Chinese communists dominate all of the mainland of China in order to accelerate this split. Once the communists succeeded in taking all of the mainland, it was necessary to make Mao Zedong as dependent on Russia as possible, so as to increase tensions. Prior to Mao's visit to Moscow in early 1950, therefore, the U.S. government refused to recognize Beijing, which meant “the Chinese Communists cannot now play off one great power against another, since they have no non-Soviet allies at the moment.” It also put extreme pressure on China by establishing the Taiwan Strait Patrol in 1950 and adopting a strategic embargo on Chinese imports.

We now know that the USSR actively intervened in the Chinese Civil War against Chiang Kai-shek and on the side of Mao Zedong and the communists. Sino-Soviet tensions were already on the rise, however, even before Mao's proclaimed victory on 1 October 1949. In August 1948, British officials were reporting that Russian officials in Dairen had begun to exclude not just Nationalist forces from the port facilities, but also “the armed forces of the Chinese Communists.” Coincidentally, right after this British report came out, the CIA submitted its own report in December 1948 that recommended the Chinese communists be allowed to dominate all of the mainland of China, without U.S. opposition, since there would probably be “no chance of a split within the Party or between the Party and the USSR,” until after the “Communist domination of China” (see Document 6).

With the beginning of the Korean conflict in 1950, the U.S. furthermore adopted a “sea denial” strategy, sending the Seventh Fleet into the Taiwan Strait to stop a planned PRC invasion of Taiwan. Fear of communist expansion along the first island chain led the U.S. government to support Taipei during the two Taiwan Strait crises in 1954–55 and 1958. Washington also felt obliged to sign security treaties supporting Chiang Kai-shek's efforts to defend a number of offshore islands from PRC attack.