The Viet Nam War ended better long term than this one did, for us. Perhaps a decisive defeat is better than US troops being used for all the wrong reasons.
The VietNam war did not end in a decisive Us military defeat. It was rather a political defeat waged by the Left in this country.
The US was never defeated militarily in Vietnam - we basically just ran away because the media told the public we were loosing ... two or three more days and the NVA would have surrendered.