US lost becase . . .

it supported corruption against the people of S. (and N.) Viet Nam. It opposed both "the will of the [S. Viet Nam] people," and their _self_-determination. Eisenhower himself knew and admitted that, had _democratic_ elections been held in Viet Nam--as was required by the Geneva Accords, 80 per cent would have voted for Ho Chih Minh.

Thus the US lost because it opposed democracy, despite its false rhetoric in support of that.