Yes, as Republicans should remember when their convention opens in less than a month, on the one-year anniversary of Donald Trump’s disparagement of John McCain as unheroic because he was “captured.” McCain was captured (with a broken leg and two broken arms) when North Vietnamese shot down his plane. He chose extra years of torture, refusing to leave when his torturers wanted to release him because he was an admiral’s son.

Trump says, however, that he, too, has been “very brave” by ignoring the danger of venereal disease during his sexual adventures: “It is a dangerous world out there — it’s scary, like Vietnam. Sort of like the Vietnam era. It is my personal Vietnam, I feel like a great and very brave soldier.” He was serious; irony is not in this narcissist’s repertoire. And there is a reason Britain’s staid Economist magazine refers to Trump’s “look of a roué gone to seed.”

“Every republic,” writes Charles Kesler, professor of government at Claremont McKenna College, “eventually faces what might be called the Weimar problem.” It arrives when a nation’s civic culture has become so debased that the nation no longer has “the virtues necessary to sustain republican government.” Do not dwell on what came after the Weimar Republic. But do consider the sufficiency of virtue that the Constitution’s framers presupposed.