During the cold war, panic over the rise of communism was all the rage. Why then did the US just ignore that China was being taken over by communists?
You might want to start with [this old answer](https://www.reddit.com/r/AskHistorians/comments/8352xc/chinese _civil_war_why_did_the_us_want_to_force/dvfqhzb/) by /u/Ethelred_IV on US insistence on maintaining the United Front.