https://www.foreignaffairs.com/ukraine/russias-adaptation-advantage
(No idea how links are showing up now)
I wouldn't put much stock in the assertions of this article -- they seem steeped in anti-Russian brainworms and cite no sources or specifics -- but this is the shit you stay up on if you're a "serious" Foreign Policy Expert. And the take it's running with today is "Russia is actually better at this than Ukraine now."
This isn't correct. The Pentagon Papers came out in '71; there were tons of significant protests before then. Draft card burning dated back to '64, all sorts of SDS activity picked up in '65, Muhammad Ali dropped his "no Viet Cong ever called me n-----" line in '66, anti-war activism was a huge aspect of the '68 election (especially the Democratic National Convention), etc. This wasn't just a youth movement, either: half of Americans viewed the war as a mistake by July '67.
The causation probably ran the other way -- opposition to the war was so widespread by '71 that it reached people in positions high enough to leak meaningful documents.