For the stay-in-office-at-all-cost representatives and senators, fear is the motivator. They are afraid that Mr. Trump might give them a nickname like “Low Energy Jeb” and “Lyin’ Ted,” or that he might tweet about their disloyalty. Or — worst of all — that he might come to their state to campaign against them in the Republican primary. They worry:

“Will the hosts on Fox attack me?”

“Will the mouthpieces on talk radio go after me?”

“Will the Twitter trolls turn their followers against me?”

My colleagues know they all just might. There’s an old Russian proverb: The tallest blade of grass is the first cut by the scythe. In private, many of my colleagues agree that the president is reckless and unfit. They admit his lies. And they acknowledge what he did was wrong. They know this president has done things Richard Nixon never did. And they know that more damning evidence is likely to come out.

So watching the mental contortions they perform to justify their votes is painful to behold: They claim that calling witnesses would have meant a never-ending trial. They tell us they’ve made up their minds, so why would we need new evidence? They say to convict this president now would lead to the impeachment of every future president — as if every president will try to sell our national security to the highest bidder.

I have asked some of them, “If the Senate votes to acquit, what will you do to keep this president from getting worse?” Their responses have been shrugs and sheepish looks.