Biden Says He Is Staying in Race in Defiant Letter to Democrats

President Biden on Monday dared his critics to “challenge me at the convention” if they want him out of the presidential race, refusing to step aside in a defiant letter to Democratic members of Congress and in fiery remarks on MSNBC’s “Morning Joe” program.

Declaring himself “frustrated by the elites” who have called for his exit from the race, Mr. Biden engaged in an offensive blitz aimed at saving his candidacy. But it also did little to mollify restless Democratic lawmakers and laid bare the fractures in his party over whether his position as its standard-bearer will help or hurt its fortunes this fall.

In effect, Mr. Biden decided to engage in a no-holds-barred fight with his allies for the world to see. He was at turns defiant, furious, indignant, exasperated and dismissive. He insisted that he would not withdraw from the race but accused those who have suggested he step aside of being routinely wrong about politics.

The president used the friendly venue of the morning news show — hosted by Joe Scarborough, a longtime supporter who recently has been critical — to respond to demands that he demonstrate the kind of vigor that was missing from his listless and at times incoherent debate performance on June 27.

Mr. Biden raised his voice repeatedly during the brief phone interview, including after Mika Brzezinski, the co-host of the show and Mr. Scarborough’s wife, asked him whether he had undergone neurological exams after the debate. Sounding exasperated and angry, Mr. Biden rejected assertions that his stamina and mental abilities have not been tested in a real way.

“It drives me nuts, people talking about this,” he said.

In the days after the debate with former President Donald J. Trump, Mr. Biden tried to be conciliatory. He admitted that he had “a bad night” and tried to explain that his performance was the result of a cold and jet lag.

Mr. Biden refused to answer a question about whether he had taken a neurological exam, even as reports surfaced that an expert on Parkinson’s disease from Walter Reed National Military Medical Center visited the White House eight times in eight months from last summer through this spring.

The records, from the official visitor logs, show that the specialist, Dr. Kevin Cannard, was at the White House at least once to meet with Mr. Biden’s physician. The reports prompted an angry back-and-forth on Monday afternoon between reporters and Karine Jean-Pierre, the White House press secretary, over a lack of transparency about the president’s health.

At 9:40 p.m. Monday, Dr. Kevin O’Connor, the White House physician, released a statement saying that “President Biden has not seen a neurologist outside of his annual physical” and implying that most of Dr. Cannard’s visits were related to treating other people who work at the White House.

As Mr. Biden’s explanations have fallen flat with some of his allies, the president has grown more impatient. That was evident on Friday night, during his prime-time interview with George Stephanopoulos of ABC News. During the interview, Mr. Biden was defiant, even bragging about his relatively small crowds at campaign rallies.

“How many people draw crowds like I did today?” he asked Mr. Stephanopoulos. “Find me more enthusiastic than today? Huh?”

On MSNBC on Monday, he went even further, repeating his longstanding answer whenever anyone has questioned whether his age means he does not have the energy to run an effective campaign.

“Come out with me. Watch me. Watch people react,” he demanded. “You make a judgment. You make a judgment.”

Less than an hour before Monday’s interview, Mr. Biden’s campaign released a letter to congressional Democrats in which the president wrote that he was “firmly committed to staying in the race,” a pointed answer to allies on Capitol Hill who have been increasingly going public with calls for him to drop out.

“The question of how we move forward has been well aired for over a week now,” Mr. Biden wrote in the two-page letter. “And it’s time for it to end. We have one job. And that is to beat Donald Trump.”

On “Morning Joe,” the president repeated his refusal to back down, saying he did not care about any of the high-ranking lawmakers or pundits who were calling for him to step aside, including Representative Jerrold Nadler of New York, the top Democrat on the Judiciary Committee, and Representative Seth Moulton, Democrat of Massachusetts.

“I don’t care what those big names think,” Mr. Biden said, his voice rising considerably.

“If any of these guys don’t think I should run, run against me,” he added. “Go ahead, announce for president. Challenge me at the convention.”

He also repeated his assertion that he was the only Democrat capable of performing the duties of the presidency, a claim that has been at the center of his argument for another four years in office and one that has animated the president’s campaign against Mr. Trump.

“Who else do you think could step in here? And do this?” he asked the hosts. “I expanded NATO.”

He made a similar case during a call with top donors, telling them, “I have one job, to beat Donald Trump.” Mr. Biden said on the call with his campaign’s National Finance Committee that he was “the best person” to do that, according to a listener who relayed the president’s remark to The New York Times. He said it was time to put Mr. Trump in the “bull’s-eye,” according to a second listener.

At a brewery in Wilmington, N.C., Jill Biden, the first lady, echoed her husband, saying that “Joe has made it clear that he’s all in” and adding that “I am all in, too.”

The letter to Democrats, the call and the impromptu interview with MSNBC came one day after several senior House Democrats said during a private conference call that they believed Mr. Biden must step down from the race, adding enormous pressure on the president and his advisers.

Mr. Biden still has support among lawmakers, including members of the Black caucus, some of whom have rallied to his side as criticism from others has mounted. Several dozen Democratic lawmakers have publicly announced that they think he should stay in the race.

But on Monday, more lawmakers indicated concern about his remaining at the top of the ticket.

Adding to the chorus of Democratic senators who are demanding that the president do more to show voters that he is fit enough to run for re-election, Senator Jon Tester of Montana, who is himself facing a difficult race, told a local TV station, KULR8, that Mr. Biden “has got to prove to the American people — including me — that he’s up to the job for another four years.”

In the letter to members of Congress — which appeared intended to head off any additional calls for him to step aside as lawmakers returned to Washington on Monday — Mr. Biden made clear that he has run out of patience with the criticism coming from Capitol Hill, the news media and elsewhere.

The letter is a rejection of the criticism, a denial of the allegations about his shortcomings and a demand for unity.

“We have 42 days to the Democratic convention and 119 days to the general election,” he wrote. “Any weakening of resolve or lack of clarity about the task ahead only helps Trump and hurts us.”

In the letter, the president made no concessions about his age or his ability to perform the functions of the presidency or engage in a rigorous campaign against Mr. Trump in the months ahead.

Instead, he argued that those trying to push him out of the race would be denying the wishes of the voters who participated in the primary process — though he noted the fact that he faced only token opposition.

“This was a process open to anyone who wanted to run. Only three people chose to challenge me,” Mr. Biden wrote. “One fared so badly that he left the primaries to run as an independent. Another attacked me for being too old and was soundly defeated. The voters of the Democratic Party have voted. They have chosen me to be the nominee of the party.”

He added: “Do we now just say this process didn’t matter? I decline to do that.”

Mr. Biden devoted much of the letter to a recitation of his record. He cited the creation of 15 million jobs, his defeat of “Big Pharma,” investments in combating climate change and the effort to improve the nation’s infrastructure. He contrasted that with what he called the economic vision of “Trump and the MAGA Republicans.”

But it is not clear whether the letter will blunt the concerns coming from his allies on Capitol Hill. It repeats the arguments that Mr. Biden has tried to make in campaign appearances since the debate and during the interview with ABC News on Friday.

Reporting was contributed by Emily Baumgaertner, Peter Baker, Katie Rogers, Theodore Schleifer, Reid J. Epstein and Lauren Hirsch.