The US didn't exactly abandon its allied in South Vietnam: https://en.wikipedia.org/wiki/Operation_Frequent_Wind#Results_of_the_evacuation https://en.wikipedia.

The US didn't exactly abandon its allied in South Vietnam: https://en.wikipedia.org/wiki/Operation_Frequent_Wind#Results_of_the_evacuation https://en.wikipedia.org/wiki/Operation_Frequent_Wind#Result... It lost the war, but that's not the same thing as just walking away frivolously, on whim.