WASHINGTON — Under pressure over his possible impeachment, President Richard M. Nixon supposedly talked to the paintings in the White House. President Bill Clinton absently toyed with his old campaign buttons. President Trump punches out Twitter messages in the lonely midnight hour.
Long after his staff has gone home, long after the lights have gone out elsewhere around the capital, the besieged 45th president hunkers down in the upstairs residential portion of the Executive Mansion venting his frustration and cheering on his defenders through social media blasts.
This is a season of conflicting impulses for a president who often seems governed by them. As the House moves toward what even he says is an inevitable vote to impeach him for high crimes and misdemeanors, Mr. Trump toggles between self-pity and combativeness. He looks forward to a Senate trial that he seems sure to win and thinks that it will help him on the campaign trail when he travels the country boasting that he had been “exonerated” after the latest partisan “witch hunt.”
But he nurses resentment over the red mark about to be tattooed on his page in the history books as only the third president in American history to be impeached. No matter what some of his critics say, advisers said he genuinely does not want to be impeached, viewing it as a personal humiliation. Even in private, he accepts no blame and expresses no regret, but he rails against the enemies he sees all around him.
“He doesn’t like what’s happening,” said Senator Lindsey Graham, Republican of South Carolina and a vocal ally who has spoken with the president several times this week. “He thinks it’s unfair. But I think he’s resolved himself that they’re going to do it, they’re out to get him. I think he’s more determined now to win than ever.”
Mr. Trump’s mood has actually improved in the past couple of weeks, advisers say, as Republicans have risen to his defense. He has grown more energized, bombarding followers with tweets and retweets defending himself and attacking his enemies.
He set a record for his presidency on Thursday with 123 total tweets in a single day, as of 11:30 p.m., eclipsing the record he had set on Sunday with 105, according to Bill Frischling of Factba.se, a service that compiles and analyzes data on Mr. Trump’s presidency.
Eighty-seven of the tweets on Thursday came from 7 to 10 a.m., just as the House Judiciary Committee was opening its marathon meeting to approve two articles of impeachment.
Mr. Trump decided against presenting a defense during a Democratic-run House inquiry he deemed unfair, conceding that a vote to impeach along party lines was inevitable. But he has set his sights on a trial in the Republican-controlled Senate as a more conducive venue to air his views about the impeachment battle and mount a defense that he imagines more like an offense.
That could put him at odds with Senate Republicans whose interests are not the same as his. Absent dramatic new revelations, Mr. Trump appears assured of escaping conviction in the Senate since that would require a two-thirds vote. But he has been eager to call witnesses Senate Republican leaders are not anxious to summon, like former Vice President Joseph R. Biden Jr. and the unidentified C.I.A. whistle-blower whose complaint kicked off the impeachment inquiry.
Senator Mitch McConnell of Kentucky, the Republican leader, talked with Mr. Trump this week about holding a relatively abbreviated trial without calling witnesses, according to a person briefed on the conversation. Mr. McConnell envisioned a trial lasting about 10 to 12 days and sought to convince Mr. Trump that a quick acquittal without the spectacle of a parade of witnesses would be better for the president.
Mr. Trump seemed amenable, but he often changes his mind and no one is certain where he will end up. He sent his White House counsel, Pat A. Cipollone, and his legislative affairs director, Eric Ueland, to meet with Mr. McConnell at the Capitol on Thursday.
Still to be determined is who will represent Mr. Trump at the trial, whether it is short or long. Mr. Trump is said to have talked with several prominent lawyers about taking on his case, but multiple people said that Mr. Cipollone had resisted bringing in new representation, leaving him to serve as lead counsel.
Among those being considered is Alan Dershowitz, the famed lawyer who represented O.J. Simpson, Jeffrey Epstein, Roman Polanski and Mike Tyson and has defended the president on television. But he would probably offer guidance from the private legal team outside the White House as Mr. Cipollone takes the lead.
For Mr. Trump, the impeachment battle has become the defining test of his presidency, weighing him down and charging him up all at once.
Some advisers said the collective burden of three years in office and the nonstop investigations had taken a toll on him. People who have spent time around him lately said he seemed fatigued and might have gained weight. Some who work in the White House have noticed that he seems more standoffish, less likely to engage in small talk with those outside his inner circle.
Concerns about his health spiked after a mysterious, unannounced weekend trip last month to the hospital. The White House insisted it was simply a head start on his annual medical checkup, but provided few details about what was done and why. His White House physician climbed into the presidential limousine for the ride to the hospital rather than travel in another vehicle in the motorcade.
Other presidents facing impeachment strove to hide how much it weighed on them, even as they brooded and raged in private. Mr. Nixon sought to give the impression it had not affected him, but behind the scenes, aides worried about his stability in the last days in the White House. He asked Henry A. Kissinger, his secretary of state, to kneel and pray with him.
“Nixon tried to hold it inside, but not too successfully,” said Evan Thomas, the author of “Being Nixon,” a biography of the president. “Remember ‘the president is not a crook’? And the sweat on his face as he said it?”
Mr. Clinton seemed to mentally disappear during meetings as his mind dwelled on the struggle to remain in office. During a Middle East peace negotiation in Gaza, an aide spied the president scribbling down on his notepad: “Focus on your job. Focus on your job.”
Mr. Trump, in his own way, is more transparent. Rather than pretend he is not bothered by the attacks on him, he lashes out at his enemies. Rather than affect a stiff-upper-lip demeanor in public, he fumes about the injustice he feels. “Trump is incapable of impulse control,” said Douglas B. Sosnik, a senior adviser to Mr. Clinton during impeachment.
Mr. Trump lately has taken the advice of some advisers by highlighting policy priorities, as Mr. Clinton did. In recent days, he advanced trade deals with China and with Mexico and Canada. During an event on child care on Thursday, he stuck largely to the script and never mentioned the word “impeachment.”
For a while after the revelations about his efforts to pressure Ukraine to help him against his Democratic rivals while withholding American security aid, Mr. Trump grew deeply upset. He felt isolated and abandoned, according to people in contact with him. He questioned why Democrats would not just let him govern. He lamented that he had done nothing wrong. He was angry at any Republican on television saying otherwise.
Since the public hearings before the House Intelligence Community, he has felt invigorated, pointing to the testimony of Gordon D. Sondland, the ambassador to the European Union who did not directly implicate Mr. Trump telling him to link the aid to his demand for investigations of Democrats, although Mr. Sondland added that he thought that was clear.
What Mr. Trump’s advisers worry about is the snapback of his anger once the impeachment process is over. They predict he will be furious, and looking for payback.
Mr. Graham said he warned Mr. Trump against that in a phone call on Wednesday night. “I just told him we know how impeachment ends, then after that your fate’s in your own hands,” Mr. Graham said. “Get back to being president and have a good story to tell.”