The White House Brushed Off Questions About Biden’s Age. Then the Debate Happened.

Ever since President Biden announced last year that he would run again, those in his inner circle closed ranks and brushed off the obvious question: No, they insisted, he was not too old to seek re-election.

The news media, they said, was unfairly fixated on his age. Republicans were posting wildly distorted video clips on social media making him look more feeble than he actually is. Hand-wringing Democrats fretting over the prospect of an octogenarian president turning 86 by the end of a second term were just “bed-wetters.”

Then the debate happened. And now the days of denial at the White House are over. No longer can the president’s confidants simply wave away concerns about his capacity after his unsteady performance at Thursday night’s showdown with former President Donald J. Trump. Struggling to contain a brush fire of alarm within the Democratic Party, his team is now forced to confront the issue head on.

Mr. Biden, 81, admitted himself on Friday that he is no longer a young man and that he has lost a step debating, even as he made a more forceful case for himself at an energized rally in Raleigh, N.C., than he had on the debate stage in Atlanta the night before. The Biden team seized on validation from Democratic allies like former President Barack Obama and Representative James E. Clyburn of South Carolina to reject calls on the president to cede the nomination to a younger candidate.

But many distressed Democrats, including some in his own administration, were left wondering how it had come to this and, fairly or not, faulted the president’s team for letting it happen: How could those closest to Mr. Biden not have talked him out of running? How could they have agreed to debate knowing that he might stumble so badly? How could they not have prepared him better for the predictable challenges during a week hidden away at Camp David?

“Last night was kind of shocking because we’d heard they’d been preparing and so on,” David Axelrod, who was a senior adviser to Mr. Obama, said the morning after the debate. “And the first 10 minutes were a disaster, and it’s hard to understand how that happened.” As it turned out, he added, “this was a great opportunity to allay people’s concerns and it had the opposite effect.”

Until now, Mr. Biden’s allies have often gone after those who raised questions about the president’s age. When the special counsel Robert K. Hur decided not to press charges against Mr. Biden for mishandling classified documents, he issued a report explaining that one factor was that the president would strike a jury as a “well-meaning, elderly man with a poor memory.” Mr. Biden’s team excoriated Mr. Hur for going beyond the bounds of his job and unfairly denigrating the president.

Mr. Axelrod was among those Democrats who had long warned of the risks of running a presidential candidate who got his start in national politics the same year that the video game Pong was introduced, candor that earned him the pique of Mr. Biden’s advisers.

But Mr. Axelrod said in an interview Friday that he did not want to second guess them. “I’m not going to disparage their thinking,” he said. Age is “a funny thing,” he said, and “it may be at the time they were saying what they were saying that he was in a different place.”

When it comes to his age, Mr. Biden can present differently depending on the moment. The two views were on display in the two events on Thursday and Friday, and they were, much like their timing, a case of night and day.

The fired-up Mr. Biden at the Raleigh rally was the one that his closest advisers see — the one with the energy to travel nine time zones from an international summit to a political fund-raiser, the one who asks sharp questions and grills unprepared aides, the one who makes wise decisions on difficult policy issues and stands up for decency against a demagogue.

The tamped-down Mr. Biden onstage in Atlanta the night before was the one his advisers do not like to see, or choose not to — the one who shuffles to the lectern, mangles his words, loses his train of thought, makes mystifying comments and stares blankly with his mouth agape rather than projecting the aura of authority and strength expected of a commander in chief.

“I think the problem is this is episodic,” said Elaine Kamarck, who worked in the White House under President Bill Clinton and is a longtime member of the Democratic National Committee. She recalled sitting just feet from Mr. Biden at an event last spring and being impressed with how masterful he was at discussing policy, remembering names and speaking without notes.

“I thought this man doesn’t have dementia, this man is fine,” she said. “That man was not the man on television last night, unfortunately. I think the problem is it comes and goes and, at this stage of life, people have good days and bad days and, unfortunately, he had a very bad night last night.”

The Democratic freakout that followed his bad night was staggering. Democrats used words like “nightmare,” “disaster” and “horrible.” Red-state Democrats were in meltdown, and Biden aides feared that donor money would dry up, diminishing what had been expected to be a financial advantage over Mr. Trump.

Mr. Biden’s team sought to buy time in hopes that the panic would subside, counseling nervous donors to wait to process what happened. The president’s allies highlighted flash polls and dial groups indicating that the overall race had not shifted following the debate. They pointed to a campaign focus group that was said to demonstrate that support for Mr. Biden among swing voters in a Midwestern state increased because they agreed with his position on critical issues.

“He didn’t have the best night on the debate stage,” Michael Tyler, the campaign communications director, told reporters on Air Force One. “But you’d rather have one bad night than a candidate with a bad vision for where he wants to take the country.” He added that there were “no conversations” about Mr. Biden stepping aside, nor were any staff changes being considered.

The president’s allies sought to turn attention to the performance of Mr. Trump, 78, which was marked by dozens of false and misleading statements and his own confusing moments. Searching for a hopeful model, Biden allies evoked John Fetterman, who won a Senate seat in Pennsylvania in 2022 despite the lingering effects of a stroke. By the end of Friday, some Democrats had returned to the fold, fearing the consequences of a Trump victory and concluding that if Mr. Biden is not likely to drop out, they needed to back him despite their worries.

If any of the president’s advisers has ever addressed Mr. Biden’s age with him in a forthright way, they have not acknowledged it. According to recent interviews with dozens of his closest aides and friends, the president engaged in no organized process outside of his family in deciding to run for a second term.

None of the advisers described a meeting or a memo that outlined pros and cons of a re-election campaign that might have addressed the consequences of age. None said they discouraged him from running or, for that matter, discussed how to address his age if he did. Instead, he simply told them to assume he was running unless he decided otherwise.

Such a conversation would be painfully difficult for presidential aides. There is something fundamentally different about raising such a personal issue with a boss as opposed to impersonal factors like battleground states, polling or policy questions.

Mr. Biden’s closest current and former aides, like Ron Klain, Anita Dunn, Jeffrey D. Zients, Steve Ricchetti, Mike Donilon, Jen O’Malley Dillon and Bruce Reed, deeply admire and respect the president. They would not want to hurt him and they see the best in him, according to fellow Democrats.

“He’s famous for having really, really loyal people,” Ms. Kamarck said. “He’s like a father to Ron Klain. What do you say to your father? This is tough, very tough.”

Mr. Klain, Ms. Dunn and other top aides declined to comment or did not respond on Friday, but White House aides on their behalf said they all supported Mr. Biden’s decision to run again and still do. Mr. Zients and Ms. Dunn held a staff meeting at the White House on Friday to calm nerves, telling aides that there are tough days in any campaign but that they would push through it together.

James Carville, who helped run Mr. Clinton’s 1992 presidential campaign, said Mr. Biden’s circle was tight. “People around President Biden have been with him forever,” he said. “I think the culture of their White House is different than the one I would be familiar with.” He added that “those people are very good” but “Ron or Mike or Anita, they’re not peers.”

Indeed, given his age and experience, Mr. Biden has few people he truly sees as peers, as much as anyone could be a peer to a president. His relations with Mr. Clinton and Mr. Obama are complicated, and some Biden advisers said he would bristle if either of those former presidents had told him last year not to run or told him now to think about dropping out. Most of the senators Mr. Biden served with for so many years, the ones whose opinions he valued, are largely gone. Ted Kaufman, his close friend and longtime aide who succeeded him in the Senate, has been one of the most supportive of a re-election bid.

The only people whom advisers believe would carry influence with him about such a profound decision would be family members, particularly Jill Biden, the first lady, who was said to have strongly encouraged a re-election campaign in the first place, and his sister, Valerie Biden Owens, who was his political consigliere through his years in the Senate.

“He’s a very proud guy,” said Mr. Axelrod, who worked alongside Mr. Biden when he was Mr. Obama’s vice president. “He’s a guy who always believes that he’s been underestimated his whole life and that he’s defied those odds. So I don’t know what his state of mind is. There are others who are close to him now. But I know there’s a lot of concern.”