Why was it difficult for the US to win the vietnam war?
The US couldn’t simply invade North Vietnam and replace its aggressive Communist government with someone less aggressive. We had to convince North Vietnam that pursuing its war against South Vietnam would be to destructive and force them to back off. However, short of occupying the country there was nothing that was going to force North Vietnam to give up. The only other course of action was to block the supply line being used to infiltrate troops and equipment into South Vietnam. As long as the United States allowed the Communists to have sanctuary in Laos and Cambodia that was not going to happen either. The last resort for the US was to train and arm the ARVN to a degree it could indefinitely hold off the NVA by itself. That almost worked, but in 1974 the Democratic Congress cut off the logistic and air support the ARVN needed to successfully fight off the next North Vietnamese invasion (which happened in 1975).
