One of the first acts of the OSS (which became the CIA) was to secretly betray official American policy and help the communists in China. They have a memorial in China today dedicated to them: https://www.nytimes.com/2017/01/01/world/asia/dixie-mission-americans-china-mao.html In fact almost all of the OSS's activities were dealing with communists and helping them take down nazi-held territory from the inside.