Kinda grossly over simplifies the Vietnam war a bit. Ignores the fact that the “democracy” we were supporting in South Vietnam was a puppet dictatorship that the South Vietnamese themselves wouldn't bother dying for much of the time. Supposes that had we marched north, the North Vietnamese would have somehow felt liberated and peace would reign free. Not that we would still be occupying firebases to this day fighting the Viet Cong in both the occupied North and the South. Deluded communists or not, at least they had a cause that freely motivated many of them to fight and keep on fighting, and leaders that they would die for like Ho Chi Minh. I mean, it’s not like the North Vietnamese had to force its soldiers to fight (compared to South Vietnam - with exceptions of course), they had a cause they believed in and our taking all their territory would not have changed that.
When did we lose the Vietnam War? Not in 1968, when we held an election that hinged on the war. None of the three candidates (Humphrey, Nixon, Wallace) were committed to unilateral withdrawal. Not during Nixon's "Vietnamization" program, in which more and more of the war effort was turned over to Vietnamese troops. In fact, Vietnamization, by all measures I know about, worked.
We lost the war when the Democrat-controlled Congress specifically banned all military aid to South Vietnam, and a beleaguered Republican president signed it into law. With Russia and China massively supplying North Vietnam, and Saigon forced to buy pathetic quantities of ammunition and spare parts on the open market because America had cut off all aid, the imbalance doomed them, and they knew it.
The South Vietnamese people were subjected to a murderous totalitarian government (and the Hmong people of the Vietnamese mountains were victims of near-genocide) because the U.S. Congress deliberately cut off military aid--even after almost all our soldiers were home and the Vietnamese were doing the fighting themselves.
We lost the war, and made it ultimately unwinnable in anything other than tactical situations, when we supported leaders like Ngo Dinh Diem, Nguyen Khanh (interim), Nguyen Van Thieu, Duong Van Minh (finale/Diem assassination), etc. and didn’t offer the Vietnamese people, either North or South a nationalistic alternative superior to communism. It started in 1945, with 1963 (the Diem assassination) being a watershed moment. Iraq is hardly Vietnam just yet, but how we handle the political aspects of the new Iraqi democracy could certainly change that.
Charon