That's interesting stuff. Retrospectives on this stuff is pretty wild.
 
And man, people kinda nailed it on Vietnam, eh? I guess there was already significant amount of history to work with by 1966, but still, they already knew it was unlikely to end in a decisive win or loss...
 

At the same time, Americans were not unrealistic about the difficulty of keeping the North Vietnamese out of South Vietnam. Just 17% in May 1966 predicted the war would end in all-out victory for the U.S. and the South Vietnamese. Most of the rest thought it would end in a compromise peace settlement (54%) or total defeat (6%).

Eventually the US loses and the North chalks up a horrific, Pyrrhic victory. The people surveyed weren't far off the mark.
 
Iraq popularity honestly don't surprise me at all, even in retrospect. It was sold effectively, it was against a country we'd already had a very popular, very quick war against, involving a genuine shitbag that people already knew, and it was close enough to 9/11 to (dishonestly) tie it to that trauma.