I was at a friend’s daughter’s confirmation party in eastern Long Island, N.Y. The family Volvo and the Tesla bore Bernie Sanders stickers, one from 2016 and the other from 2020. “The thing about Trump . . .” I began, and the father interrupted me: “. . . he’s not all bad, right?” he said. “I actually like some of the things he’s doing.” He mentioned North Korea and trade protectionism. He cast his eyes about, worried about being overheard.

My friend didn’t vote for Donald Trump and doesn’t intend to in 2020. But he doesn’t...