The answer is, follow the money.

What, after all, do retired officials do for a living? Many become lobbyists, and in an era of extreme polarization that means lobbying their own party. Being honest about why you quit would be bad for future business.

Beyond that, the modern U.S. right contains many institutions — Fox News and other media, right-wing think tanks, and others — that offer sinecures to former officials. However, this “wing-nut welfare” — which has no counterpart on the left — is available only to those who continue to toe the line.

Earlier I mentioned David Brat, who ousted Eric Cantor. As it happens, Brat himself was defeated in last year’s Democratic landslide. So what’s he doing now? He’s dean of the business school at Jerry Falwell Jr.’s Liberty University.

So financial incentives keep even retiring Republicans in line. And the exceptions prove the rule.

As far as I can tell, Gordon Sondland, who is ambassador to the European Union — but surely not for long — was the first political appointee, as opposed to professional civil servant, to attest to the Trump administration’s abuse of power in Ukraine. A key point about Sondland, however, is that he’s a rich man who doesn’t need wing-nut welfare.

He’ll live comfortably in retirement as long as he doesn’t go to jail. So his incentives were very different from those facing most G.O.P. figures.

So are all Republicans corruptly subservient to Trump? No, there are some honorable Never Trumpers, including many of the foreign-policy neocons like William Kristol. Some of us will never forgive this group for misleading us into war, but it turns out that they really do have principles, and deserve recognition for their current political courage.

But the modern G.O.P. as a whole is overwhelmingly fanatical, corrupt, or both. Anyone imagining that the mountainous evidence of Trump’s malfeasance will lead to a moral awakening, or that Republicans will return to democratic political norms once Trump is gone, is living in a fantasy world. Even catastrophic electoral defeat next year probably wouldn’t do much to change Republican behavior.