So, most American children know Vietnam was an ally of the Soviet Union and China as their "proxy". The thing is that it was an uneasy alliance.
Historically Vietnam has never really trusted China and China has never liked Vietnam. Ho Chi Minh himself, with his love of the U.S. Constitution and Declaration of Independence seems to have been more open to a socialist democracy than a "true" socialist state. Ho Chi Minh might have been a communist more by necessity (to gain independence), and the Comintern tried to keep Vietnam on a short leash.
So what if the United States, instead of fighting in Vietnam, sees a golden opportunity to stop Communist influence spreading in Asia, and instead tries to have a more anti-colonial French government take power, and tries to get Ho Chi Minh to become a democratic leader?