Trump’s message, we are incessantly told, is that the GOP has double-crossed its constituency with trade, immigration and just about anything else you can name. But it will do the Republican Party no good to win back the aggrieved at the cost of everyone else — not to mention what is good for the country.

A glance at Trump’s endorsees — check his Web page — is an effective appetite suppressant. Imagine a Republican National Convention’s dais stocked with some of the people who have already endorsed Trump — not just the feckless Chris Christie or the bizarre Sarah Palin, but such figures as the disgraced football player Richie Incognito, Hulk Hogan and Teresa Giudice, from “The Real Housewives of New Jersey,” a fresh alumna of the federal prison system. A meeting of Trump supporters might have to be sanctioned by a pro wrestling promoter.

When I spotted that Republican official, I did not say what I initially wanted to. I wanted to say that we are taking names — “we” being the American people. We will remember who endorsed a man who took American politics lower than it has ever been, no doubt extracting promises of good behavior that later will be broken. Party unity will not wash. The GOP is going to lose, the only question is how — with some honor, or craven and deservedly mocked by history.