Top Democrats have ruled out the possibility of replacing US President Joe Biden as their presidential nominee after a feeble debate performance.

Instead they have called on party members to focus on the consequences of a second Donald Trump presidency.

After days of hand-wringing about Biden’s poor night on stage during last week’s debate against Trump, Democrats leaders have firmly rejected calls for their party to choose a younger presidential candidate for the November 5 election.

Biden, 81, meanwhile was huddled with family at the Camp David presidential retreat on Sunday (local time), with his political future a likely topic of discussion.

But the drumbeat of calls for Biden to step aside continued.

A post-debate CBS poll showed a 10-point jump in the number of Democrats who believe Biden should not run for president, to 46 per cent from 36 per cent in February.

“The unfortunate truth is that Biden should withdraw from the race, for the good of the nation he has served so admirably for half a century,” the Atlanta Journal-Constitution said in an editorial on Sunday.

“The shade of retirement is now necessary for President Biden.”

“Absolutely not,” responded Georgia Democratic senator Raphael Warnock, one of several Democrats seen as a possible replacement for Biden.

“Bad debates happen,” he told NBC’s Meet the Press program.

“The question is, ‘Who has Donald Trump ever shown up for other than himself and people like himself?’. I’m with Joe Biden, and it’s our assignment to make sure that he gets over the finish line come November.”

House of Representatives Democratic leader Hakeem Jeffries, who could become speaker next year if his party can take control of the House in November’s elections, acknowledged that Biden suffered a setback in his debate with Trump, the Republican candidate.

“I believe a setback is nothing more than a setup for a comeback,” he told MSNBC.

“The moment that we’re in right now is a comeback moment.”

Senator Chris Coons of Delaware, a leading Biden surrogate, told ABC’s This Week program that Biden needed to stay in the race to ensure Trump’s defeat.

“I think he’s the only Democrat who can beat Donald Trump,” Coons said.

With Democratic leaders rallying around his candidacy, it will be up to Biden to decide whether he wants to end his re-election bid.

But other Democrats held open the possibility of choosing a different presidential candidate.

Representative Jamie Raskin, a prominent Democrat in Congress, told MSNBC that there were “very honest and serious and rigorous conversations” within the party.

“Whether he’s the candidate or someone else is the candidate, he’s going to be the keynote speaker at our convention. He will be the figure that we rally around to move forward,” Raskin said.

During the debate, a hoarse-sounding Biden delivered a shaky, halting performance in which he stumbled over his words on several occasions.

Some Democrats later said privately that the showing could prove to be a disqualifying factor.

In his own debate performance, Trump repeated well-worn falsehoods, including claims that migrants are behind a crime wave, that Democrats support infanticide, and that he actually won the 2020 election.

After a frenzied run of seven campaign events across four states since last Thursday’s debate, Biden headed to Camp David on Saturday for a planned family gathering that included a family photo shoot, according to two people familiar with the scheduling.

Also there are his wife, Jill Biden, as well as the Biden children and grandchildren.

The trip had been planned for months, but the timing and circumstances of Biden being surrounded by family members who have weighed heavily in his past decisions to run for the presidency have added to the scrutiny around the visit.