WASHINGTON — President Trump began Monday as he has started so many other presidential mornings — by unleashing a blistering Twitter attack on critics who suggested his 2016 campaign colluded with the Russians.
By the afternoon the director of the F.B.I., James B. Comey, had systematically demolished his arguments in a remarkable public takedown of a sitting president. Even a close ally of Mr. Trump, Representative Devin Nunes, Republican of California and the House Intelligence Committee chairman, conceded that “a gray cloud” of suspicion now hung over the White House by the end of the day’s hearings.
The testimony of Mr. Comey and that of Adm. Michael S. Rogers, his National Security Agency counterpart, will most likely enervate and distract Mr. Trump’s administration for weeks, if not longer, overshadowing good news, like the impressive debut of Judge Neil M. Gorsuch, his Supreme Court nominee, on the first day of his confirmation hearings Monday.
But it’s the obsessiveness and ferocity of Mr. Trump’s pushback against the Russian allegations, often untethered from fact or tact, that is making an uncertain situation worse.
Mr. Trump’s allies have begun to wonder if his need for self-expression, often on social media, will exceed his instinct for self-preservation, with disastrous results both for the president and for a party whose fate is now tightly tied to his.
“The tweets make it much more difficult for us as we try to build a case against these leakers,” said Representative Peter T. King, a New York Republican who sits on the Intelligence Committee. “We always have to be answering questions about the tweets — it puts us on defense all the time when we could be building a case for the president.”
And Mr. Trump’s fixation on fighting is undermining his credibility at a time when he needs to toggle from go-it-alone executive action to collaborative congressional action on ambitious health care, budget and infrastructure legislation.
“I don’t always like what the president is saying,” the Senate majority leader, Mitch McConnell, told The Washington Examiner last month. “I do think he frequently, by wading into other matters, takes attention away” from “the very substantial things we’re already accomplishing.”
A Gallup poll released Monday found Mr. Trump with an abysmal 37 percent approval rating; other recent polls place his popularity in the mid-40s, but even that level is among the lowest ever recorded for a president this early in his first term.
Over the past several weeks, Republicans in Congress and members of their staffs have privately complained that Mr. Trump’s Twitter comment on March 4 — the one where he called Barack Obama “sick” and suggested that the former president had ordered a “tapp” on his phone — had done more to undermine anything he’s done as president because it called into question his seriousness about governing.
The problem, from the perspective of Mr. Trump’s beleaguered political fire brigade, is that the president insists on dealing with crises by creating new ones — so surrogates, repeating talking points the president himself ignores, say they often feel like human shields.
Within the White House, a number of Mr. Trump’s advisers — including the press secretary, Sean Spicer, who has himself repeated unsubstantiated claims of British spying on Mr. Trump — have told allies that Mr. Trump’s Twitter habits are making their jobs harder, said administration officials interviewed over the past week. Mr. Spicer said he has no problem with his boss’s tweeting. “It’s just not true. I have not commented on the tweets to anyone including my wife,” he said in an email.
Most politicians, perhaps any other politician, would have backed away from the Russia story, and left the defense to surrogates or unexpected validators like Mike Morrell, the former acting director of the C.I.A., who said last week that “there is smoke, but there is no fire at all” in the allegations that the Trump campaign colluded with Russia.
But this president, a proponent of do-it-yourself crisis communications with boundless self-confidence in his capacity to shape the story, seems determined to hug his Russian hand grenade.
Monday morning began not with praise of Judge Gorsuch — or an exhortation of House Republicans to quickly pass a revamped Obamacare repeal — but with six protective-crouch tweets about the Russia investigation.
“The Democrats made up and pushed the Russian story as an excuse for running a terrible campaign. Big advantage in Electoral College & lost!” Mr. Trump wrote shortly after dawn, using his private Twitter account.
Then, a few minutes later: “The real story that Congress, the FBI and all others should be looking into is the leaking of Classified information. Must find leaker now!”
People close to the president say Mr. Trump’s Twitter torrent had less to do with fact, strategy or tactic than a sense of persecution bordering on faith: He simply believes that he was bugged in some way, by someone, and that evidence will soon appear to back him up.
Plus he just likes to mix it up. He fired off his ill-fated Saturday tweet complaining of “tapps” of his phones after railing to aides about how poorly Attorney General Jeff Sessions had responded to reports that he had surreptitiously communicated with the Russians, the way Mr. Trump’s former National Security Council adviser, Michael T. Flynn, did.
The president, people close to him have said over the last several weeks, has become increasingly frustrated at his inability to control the narrative of his action-packed presidency, after being able to dominate the political discourse or divert criticism by launching one of his signature Twitter attacks.
“I think that maybe I wouldn’t be here if it wasn’t for Twitter,” Mr. Trump told a sympathetic interviewer, Tucker Carlson of Fox News, last week.
Still, there’s some evidence that the president’s magic medium is losing its effectiveness, in part because Mr. Trump’s Twitter persona seems to have shifted from puckish to paranoid.
Focus groups and polls conducted by two Democratic strategists this month have shown that many voters, even some who support Mr. Trump, have grown weary of his tweets as president. That was also borne out by a Fox News poll last week, showing that a mere 35 percent of Trump voters approve of his Twitter habits, and that only 16 percent of all voters approve of them. Some 32 percent said they “wish he’d be more careful” with his feed.
“His tweeting defines him, and not in a good way,” said Geoff Garin, a veteran Democratic pollster. “Voters not only think Trump’s use of Twitter is unpresidential, they also see the tone and content of his tweets as an indication that he is lacking in self-control.”
Mr. Comey seemed to tacitly agree.
In midafternoon came a tweet from Mr. Trump’s official @potus account: “FBI Director Comey refuses to deny he briefed President Obama on calls made by Michael Flynn to Russia.”
A dour and disapproving Mr. Comey instantly fact-checked the tweet when it was read out loud to him. “No,” he said. “It was not our intention to say that today.”