This constituency, the gainfully employed but insecure lower middle class, is the Trumpian core. By embracing white identity politics, they’re being bigoted but also, in their own eyes, imitative: Trump’s protectionist argle-bargle boils down to a desire to once again have policies that specifically benefit lower-middle-class whites — welfare for legacy industries and affirmative action for white men.

This crude attempt at imitation, unfortunately, is part of a very common iterative cycle in politics. It’s a reason why, in multiethnic societies, multiracial parties are the exception rather than the rule.

And breaking that cycle won’t be easy for either party. The activist energy on the left is pushing for a more ethnically focused politics, devoted to righting structural race-based wrongs. That energy will be blunted temporarily by the flight of well-educated whites from Trump, but the absence of economic common ground between Hillary-voting white moderates and the party’s poorer, minority base means that her temporary coalition is likely to fracture first along racial lines.

That fracturing will help the G.O.P. recover, but it won’t help Republicans build a pan-racial conservatism. The pull of white identity politics can be overcome, but only with great effort. Not least because it requires not only that conservatism change, but that minority voters be persuaded that the change is meaningful.