Bob Corker, part of the dying-in-the-dark-isn’t-so-bad caucus during the primary campaign (and when he seemed to hope for a cabinet appointment), has become a fierce Trump critic — but only after deciding to retire from the Senate. George W. Bush and John McCain have each given speeches that read like broadsides against Trump — but very general critiques of his worldview, not political attacks on the man himself. And now Jeff Flake of Arizona has delivered a barnburner of a Senate address about the civic costs of the Trump presidency — while simultaneously declaring that because he can’t win his primary in a Trumpified party, he won’t even stay and fight it out.

To the extent that there’s a plausible theory behind all of these halfhearted efforts, it’s that resisting Trump too vigorously only strengthens his hold on the party’s base, by vindicating his claim to have all the establishment arrayed against him.

But the problem with this logic is that it offers a permanent excuse for doing nothing, no matter how bad Trump’s reign becomes. (“I’d criticize him for accidentally nuking Manila, but you know, then Fox News would just make it all about me …”) In the end, if you want Republican voters to reject Trumpism, you need to give them clear electoral opportunities to do so — even if you expect defeat, even if it’s all but certain. And an anti-Trump movement that gives high-minded speeches but never mounts candidates confirms Trump’s claim to face establishment opposition while also confirming his judgment of the establishment’s guts and stamina — proving that they’re all low-energy, all “liddle” men, all unwilling to fight him man to man.

If Corker really means what he keeps saying about the danger posed by Trump’s effective incapacity, he should call openly for impeachment or for 25th Amendment proceedings — and other anti-Trump Republicans should join him. If Flake really means what he said in his impassioned speech, and he doesn’t want to waste time and energy on a foredoomed Senate primary campaign, then he should choose a different hopeless-seeming cause and primary Trump in 2020. George W. Bush should endorse him. So should McCain, and Corker, and Romney, and Kasich, and Sasse, and the rest of the anti-Trump list. They should expect to lose, and badly, but they should make Trump actually defeat them, instead of just clearing the field for his second nomination.

And not only for the sake of their honor. The president’s G.O.P. critics should engage in electoral battle because the act of campaigning, the work of actually trying to persuade voters, is the only way anti-Trump Republicans will come to grips with the legitimate reasons that their ideas had become so unpopular that voters opted for demagoguery instead.

A speechifying anti-Trumpism, distant from the fray, will always be self-regarding and self-deceiving — unwilling to see how the Iraq War discredited both the Bushist and McCainian styles of right-wing internationalism, incapable of addressing the economic disappointments that turned voters against Flake’s Goldwaterite libertarianism and Romney’s “trust me, I’m a businessman” promises. Only in actual political competition can the Republican elite reckon with why it lost its party, and how it might win again without succumbing to Trumpian indecency.