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 with the elites” who have called for his exit from the race, Mr. Biden used the friendly venue of the morning news show to respond to demands that he demonstrate the kind of vigor that was missing from his listlessdebate performance on June 27.
Mr. Biden raised his voice repeatedly during the brief phone interview, including after one of the hosts asked him whether he had taken 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.
Less than an hour before the 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, released by his campaign. “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 didn’t 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 from 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 former President Donald J. Trump.
“Who else do you think could step in here? And do this?” he told the hosts. “I expanded NATO.”
The letter and the impromptu interview come 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.
In the letter — which appeared intended to head off any additional calls for him to step aside as lawmakers returned to Washington on Monday — Mr. Biden appears to have run out of patience with the chorus of criticism coming from Capitol Hill, the news media and elsewhere.
The two-page 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 say this process doesn’t matter? I decline to do that.”
Mr. Biden devotes much of the letter to a recitation of his record. He cites 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 contrasts that with what he calls 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 an interview with ABC News on Friday.