US President Joe Biden forcefully tried on Friday to quell Democratic anxieties over his unsteady showing in his debate with former president Donald Trump, as elected members of his party closed ranks around him in an effort to shut down talk of replacing him.

Mr Biden’s halting delivery and meandering comments, particularly early in Thursday evening’s debate, fuelled concerns from even members of his own party that at the age of 81 he is capable of leading the country for another four years.

It created a crisis moment for Mr Biden’s campaign and his presidency, as members of his party flirted with potential replacements, and donors and supporters could not contain their concern about his showing against Mr Trump.

Mr Biden appeared to acknowledge the criticism during a rally in Raleigh, North Carolina, saying: “I don’t debate as well as I used to.”

But he added: “I know how to do this job. I know how to get things done.”

Speaking for 18 minutes, Mr Biden appeared far more animated than he had the night before as he criticised Mr Trump for his “lies” and for waging a campaign aimed at “revenge and retribution”.

“The choice in this election is simple,” Mr Biden said. “Donald Trump will destroy our democracy. I will defend it.”

He added, alluding to his candidacy: “When you get knocked down, you get back up.”

President Joe Biden, right, and Republican presidential candidate former president Donald Trump, left, stand on stage during a break in a televised presidential debate
President Joe Biden, right, and Republican presidential candidate former president Donald Trump, left, stand during a break in the presidential debate hosted by CNN (John Bazemore/AP)

First lady Jill Biden, at a Friday evening fundraiser in New York City, said her husband told her after the debate, “I don’t know what happened. I didn’t feel that great”.

But she seconded the president in stressing that he tells the truth and he bounces back from adversity.

Even before the debate, Mr Biden’s age had been a liability with voters, and Thursday night’s face-off appeared to reinforce the public’s deep-seated concerns before perhaps the largest audience he will garner in the four months until election day.

Privately, his campaign worked to reduce concerns and keep donors on board. Democratic politicians on Friday acknowledged Mr Biden’s poor showing, but tried to stop talk of replacing him as their standard-bearer, and instead shift the focus to Mr Trump’s attacks and falsehoods.

“Well, the president didn’t have a good night, but neither did Donald Trump with lie after lie and his dark vision for America,” said North Carolina governor Roy Cooper, hours before he introduced the president in Raleigh. “We cannot send Donald Trump back to the White House. He’s an existential threat to our nation.”

Former president Barack Obama backed up his former vice president, posting on X that “Bad debate nights happen”.

Alluding to his own poor showing in the first debate of his re-election campaign in 2012, Mr Obama continued: “Trust me, I know. But this election is still a choice between someone who has fought for ordinary folks his entire life and someone who only cares about himself.”

He added: “Last night didn’t change that, and it’s why so much is at stake in November.”

House Democratic leader Hakeem Jeffries answered with a flat “no” when asked Friday if Mr Biden should step aside.

Mr Biden’s campaign billed the Raleigh event as the largest-yet rally of his re-election bid in the state Mr Trump carried by the narrowest margin in 2020. He then travelled to New York for a weekend of big-dollar fundraisers that his campaign now needs more than ever.

Mr Biden’s campaign announced that it raised 14 million dollars on debate day and the morning after, while Mr Trump’s campaign said it raised more than eight million dollars from the start of the debate through to the end of the night.

Vice president Kamala Harris, whom the Biden campaign sent out to defend his performance, tried to reassure Biden supporters at a rally in Las Vegas on Friday, saying: “This race will not be decided by one night in June.

“This race will be decided by you. By us. Who sits in the White House next year will be determined by what we together do in these next 130 days.”

Biden campaign communications director Michael Tyler said there had been no internal conversations “whatsoever” about Mr Biden stepping aside, though he, too, acknowledged that the president had a “bad night” on stage.

Mr Biden and his team have long wagered that voters would look past their concerns about his age and unpopularity when confronted at the ballot box with a choice between the president and Mr Trump. Despite their concerns about Mr Biden’s performance, they took solace in Mr Trump doing little to expand his own appeal to voters on Thursday.

Polls from CNN and 538/Ipsos conducted soon after the debate found that most debate-watchers thought Mr Trump outperformed Mr Biden. But the two men’s approval ratings remained largely unchanged, just as they did in the aftermath of Mr Trump’s conviction.

Democrats seized on Mr Trump’s equivocations on whether he would accept the will of voters this time around, his refusal to condemn the rioters who stormed the Capitol on January 6 2021, trying to overturn his 2020 loss to Mr Biden, and his embrace of the conservative-leaning Supreme Court’s overturning of Roe v Wade that had legalised abortion nationwide.

President Joe Biden and first lady Jill Biden wave at a campaign rally
President Joe Biden and first lady Jill Biden at a campaign rally (Evan Vucci/AP)

But Mr Biden fumbled on abortion rights, one of the most important issues for Democrats in this year’s election. He was unable to explain Roe v Wade, the landmark Supreme Court ruling that legalised abortion nationwide. A conservative Supreme Court with three justices nominated by Mr Trump overturned Roe two years ago.

As elected Democrats united behind Mr Biden publicly, donors and party operatives shared panicked text messages and phone calls on Thursday night and into Friday expressing their concern that Mr Biden’s performance was so bad that he may be unelectable this autumn.

Among the few public Democratic voices calling on Mr Biden to step aside was congressional candidate Nancy Boyda in Kansas, who broke with most in her party and called on Mr Biden to suspend his campaign and retire at the end of his current term.

But there were no immediate signs of organised efforts among donors, his campaign leadership or the Democratic National Committee to convince the president to step aside.

Under current Democratic Party rules, it would be difficult, if not impossible, to replace Mr Biden as the party’s nominee without his co-operation or without party officials being willing to rewrite the rules at the August national convention.