Here’s the problem: When you remove that person, who is left to take responsibility? It’s certainly not Rod Rosenstein, the deputy attorney general (and the new head of the Russia investigation), who recommended Mr. Comey’s firing. Without Mr. Comey, Washington is sorely lacking a person willing to ensure that the Russia matter is investigated properly, that the F.B.I. is protected from politics and that if political appointees in the Justice Department pass the buck, there’s at least someone who will not. Mr. Comey may have had a tendency to lurch for the buck across the table, but his departure leaves us with leadership that will do anything to avoid handling it.

Third, Mr. Comey is genuinely fixated on independence and doing the right thing. In 2004, when he was deputy attorney general, he stood up to President George W. Bush over the National Security Agency’s warrantless wiretapping program. He stood up to Mrs. Clinton, too, when he rekindled an investigation of her, even though everyone expected her to be elected president a few weeks later and thus be in a position to fire him. He has stood up to Mr. Trump.

Mr. Comey is often criticized for an obsession with his own rectitude. And it’s certainly true that when a damn-the-torpedoes decision backfires, the result is explosive. That’s what happened last year when Mr. Comey made a judgment about how to proceed in the Clinton email affair — and then Mr. Trump unexpectedly won. It understandably makes people angry when Mr. Comey responds, as he recently did in congressional testimony, that he doesn’t think considering the political consequences of his action would have been proper and that even knowing what he now knows, he would act the same way again.

But that same insistence on standing up to power and doing what is right irrespective of consequences is the main thing since Jan. 20 that has stood between President Trump and impunity. Whatever you think of Mr. Comey’s judgment, he will do what he believes to be right, whomever it might help or hurt politically and whatever damage it might do to him and his reputation. Who else can you say that about?

This constellation of human traits has virtues and vices, and the two are intertwined. But I do think we’re going to miss those very features of Mr. Comey that so many Americans have come to hate over the past year. And it is, I believe, those very features that led Mr. Trump to fire the F.B.I. director.

Because at the end of the day, Americans need someone to count on to tell the truth (even if a bit too much of it and at the wrong moment), who will take responsibility as others duck it (even if that sometimes looks self-centered and preening) and who will do the right thing as he sees it whatever the cost (even if the cost to himself and the country is terrible). If you’re President Trump, there’s nothing scarier than such a person.