The Republican members of the Senate Intelligence Committee didn’t put up much of a defense of President Donald Trump’s character at a hearing last Thursday, when James Comey, the former F.B.I. director, described the events that had led to the President’s firing him. Instead, they generally praised Comey for his honor and his service, even after he said that he had felt the need to memorialize his meetings with Trump because of “the particular person” he was dealing with. “I was honestly concerned that he might lie,” Comey said of the President of the United States.

The closest that the Republicans came to a counteroffensive was when they wondered why Comey hadn’t got Trump some help. Marco Rubio, of Florida, suggested that Comey could have informed the White House counsel that “someone needs to go tell the President that he can’t do these things.” These “things” included his asking everyone at an Oval Office meeting, including Comey’s direct boss, Attorney General Jeff Sessions, to leave the room so that Trump could lean on Comey to drop the F.B.I.’s investigation of Michael Flynn, the former national-security adviser, and his contacts with Russian officials.

The President shouldn’t require tutoring on the basics of obstruction of justice. Still, Comey said that he had tried to make the parameters of their relationship clear. He had explained to the President how important it was that the F.B.I. be independent. In an extraordinary move, Comey had also visited the Attorney General to “implore” him to never again leave him alone in a room with the President.

Sessions is a singularly compromised choice to fill the role of protector of investigative independence, though, and not just because he was one of Trump’s earliest and most avid supporters and the first senator to endorse him. During his confirmation hearings, Sessions had misrepresented his own contacts with Russian officials, and, at the time of the Oval Office meeting, Comey believed, rightly, that Sessions would soon recuse himself from the investigation of Russia’s role in the 2016 campaign.

One effect of Comey’s appearance has been to create an imperative that Sessions himself be called to testify before Congress. The Attorney General had tried to linger after being asked to leave the Oval Office. Was it because, as Comey thought, he suspected that something improper was about to happen? What was Sessions thinking when Comey asked that he not be left alone with the President? And when Sessions wrote a letter that Trump used to justify firing the F.B.I. director, was he, as Senator Ron Wyden, of Oregon, asked on Thursday, violating the terms of his recusal? “It’s a reasonable question,” Comey said.

What is most striking about Comey’s story, however, is that, in asking to get out of the room with the President, he was seeking the opposite of what so many other people in Washington seem to want. In the opening remarks that Comey had prepared for the committee, he described the door in the Oval Office, “next to the grandfather clock,” cracking open, and his catching a glimpse of Reince Priebus, the chief of staff, with a clutch of people in line behind him, like courtiers in a Renaissance painting, waiting for an audience.

There is something like a mass delusion, in policy circles and beyond, that if a sensible person can be the last one to speak with Trump before he makes a decision, the right decision will be made, and the Republic—or, at least, the Paris climate accord or our relations with nato allies—will be saved. This theory is often based on the notion that Trump has no ideology or deeply held policy preferences, and therefore that he is an empty vessel, ready to be filled with the instruction of the wise, or the merely clever.

But if Trump lacks principles it is not because no one has ever bothered to present him with any. He is not some child of nature. He does have beliefs, and prejudices, centered on his own power and prerogatives. Comey said that Trump told him he had a “need” for loyalty. There have also been reports, in the Times and elsewhere, that Trump is furious with Sessions for recusing himself and thus leaving the investigation in more independent hands, and that Sessions offered to resign.

Others may yet realize that being in a closed room with Trump can be morally suffocating. Comey provided a model of how to move into the “public square,” as he put it, by recording doubts about the Chief Executive in memos, in order to be able to speak about them accurately when the need arose. Senator Roy Blunt, of Missouri, asked Comey why he had felt free to give those memos to a friend, a professor at Columbia Law School, who had, in turn, given them to the press. Trump’s lawyer later referred to this as an “unauthorized disclosure” of “privileged communications.” On Friday, the President tweeted, “WOW, Comey is a leaker!”

Comey, however, says that he was careful to keep classified information out of those memos, limiting their contents to material that “as a private citizen, I felt free to share.” He added that he might have made them public sooner, but feared that it would be the President’s word against his. (Indeed, at a press conference on Friday, Trump said that he was willing to testify that Comey had lied under oath.) It was a Trump tweet, suggesting that the President might have taped their meetings, that prompted Comey to make his version public, because he thought that recordings would corroborate his story. “Lordy, I hope there are tapes,” he told the committee.

If there are tapes, Robert Mueller, the Special Counsel, if not Congress, needs to get them to help determine if Trump obstructed justice. Whether such a finding would ever lead to a bill of impeachment, which requires a majority of votes in the House of Representatives, depends on the internal politics of the G.O.P. The 2018 midterms aren’t far off, though, and the sight of someone like James Comey calling the President a liar has the potential to rouse voters. In the meantime, more of Trump’s advisers and enablers may head for the door, or be shown out, but it is possible for a person to govern in isolation for quite a while, or at least to exploit the instruments of government, to fantastically disastrous effect. And Trump wouldn’t need much help with that. ♦