I was too young for VN, but have traveled there quite a bit and know a large number of former ARVN officers and enlisted as well as former civilian employees (all through wifey who is Vietnamese).
One of the most poignant comments I've ever heard came from a former civilian employee who's still (trapped) in VN - he was highly trained in the US and speaks flawless English, though now he's pretty much blacklisted because of his previous line of work.
Anyway we were talking about 1975 and he was saying "Terrible, terrible, we didn't know how bad it was going to be", and etc, until he finally looked me in the eye and said "Why did America abandon us? I can't understand that. We were winning, and America abandoned us."
What was I gonna' do, explain John Kerry and Jane Fonda to him?
Not only did we not give them every thing we promised them when we pulled out, we didn't even make up their ammunition expenditure for the 1972 Easter Offensive. It was a Democratic congress that cut the funding with Ted Kennedy in the lead.