This surprised me:

Negative views of each of our recent wars rise with age. Under-30s are the least likely to say that Iraq, Afghanistan, and Vietnam were mistakes. This surprises me because young people voted overwhelmingly for Barack Obama in 2008, when he was seen as the most antiwar of the major Democrats. In contrast, seniors voted for George W. Bush in 2004, for John McCain in 2008, and for Mitt Romney in 2012. Yet they are more likely to see Iraq and Vietnam as a mistake than the under-30s, and for Vietnam, there is a 27-point gap.

(I acknowledge that nine years have  passed since 2004. Today’s 18-29s were far too young to vote in that election, and some of today’s seniors were just 56. But still, the age pattern seems strong and almost monotonic.)