When the USA began sending " advisors ", under JFK, to Nam, the anti-war movemnet was a tiny group of Commies/ Socialists/ Ban the Bombers / anti-war warriors, who had been around during WW II and Korea and the Cuban Missle Crisis. The more they engaged, the louder they became, the more publicity they got, and the more LBJ micromanaged ( with McNanmara, et al ) and made a mess of things, the more adherents they attractted. Those, who went over to their side, gave aid and comfort to our enemies, as well as to those they banded with. Some people, call them what you will, are attracted to numbers ... NOT positions.
That is the problem with supposed Conservatives ( and this includes FREEPERS and ex administration GOPers , retired generals, etc. )agreeing with the likes of Asner, Fonda, Gore ( who has flip- flopped now, so many times, on this matter, that he looks like a wooden puzzle piece ), etc.