Take, for instance, David Brooks’s insistence a month ago that Marco Rubio needs to denounce Trump more forcefully if he is to prevail. “I’m sorry, Marco Rubio, when your party faces a choice this stark, with consequences this monumental, you’re probably not going to be able to get away with being a little on both sides.” This high-minded sentiment is actually closer to the opposite of reality. The way to consolidate leadership of a political party is not to polarize it but to straddle its divide. Trump’s most plausible opponents have doled out their rebuttals in carefully calibrated doses. “Well, that’s not my policy,” says Cruz.

Rubio goes a bit further: “I disagree with Donald Trump’s latest proposal. His habit of making offensive and outlandish statements will not bring Americans together.” But note the contrast between Rubio’s condemnation of Trump’s anti-Muslim bigotry and his earlier condemnation of Obama’s rejection of anti-Muslim bigotry. Rubio impugns Obama’s motives for rejecting discrimination against Muslims. (“Cynicism”!) He makes no such judgment about Trump’s motives. Rubio needs to harness the same passions that Trump is exploiting, but to do so more carefully. His anti-anti-bigotry message cleverly redirects conservative resentment away from Muslims and toward the liberals who cynically denounce anti-Muslim prejudice and refuse to present the case against ISIS as a war of civilizations.

Parliamentary systems channel far-right nationalistic movements of the sort Trump is leading into splinter parties. The American winner-take-all system creates two blocs that absorb far-right movements into the mainstream. Rubio, like all the Republican contenders, has promised to endorse Trump if he wins the nomination, a constraint that limits their ability to denounce him. You can’t call a man a fascist while promising to support him if he collects the requisite delegates. Unless Republican elites are willing to actually cleave the GOP in two — and they have displayed no such inclination — they are going to live with the reality that they are part of an entity that is substantially, if not entirely, a party of Trump.