US President Joe Biden says he intends to defeat Republican rival Donald Trump in the November presidential election, giving no sign that he would consider dropping out of the race after a feeble debate performance that dismayed many of his fellow Democrats.
"I know I'm not a young man, to state the obvious," an ebullient Biden said at a rally one day after the head-to-head showdown with his Republican rival, which was widely viewed as a defeat for the 81-year-old president.
"I don't walk as easy as I used to, I don't speak as smoothly as I used to, I don't debate as well as I used to," he said, as the crowd chanted "four more years".
"I would not be running again if I didn't believe with all my heart and soul that I could do this job. The stakes are too high," Biden said.
"The choice in this election is simple," 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".
Biden's verbal stumbles and occasionally meandering responses in the debate heightened voter concerns that he might not be fit to serve another four-year term and prompted some of his fellow Democrats to wonder whether they could replace him as their candidate for the November 5 U.S. election.
Trump, 78, made a series of exaggerated claims during the debate that mostly went unchecked by his opponent.
Hakeem Jeffries, the Democratic Party leader in the US House of Representatives, avoided answering directly when asked if he still had faith in Biden's candidacy.
“I support the ticket. I support the Senate Democratic majority. We're going to do everything possible to take back the House in November. Thank you, everyone,” he told reporters.
Other Democrats likewise demurred when asked if Biden should stay in the race.
"That's the president's decision," Democratic Senator Jack Reed told a local TV station in Rhode Island.
The Biden campaign said it raised $US14 million ($A21 million) on Thursday and Friday and posted its single best hour of fundraising immediately after the Thursday night debate.
The Trump campaign said it raised $US8 million on the night of the debate.
About 48 million TV viewers tuned in to watch Thursday's debate, according to preliminary Nielsen data.
The number suggests the final audience will be about one-third lower than the 73 million people who watched the candidates’ first face-off in 2020, and among the three lowest-rated first presidential debates since 1976.
The relatively low number compared to past debates in recent election cycles could be indicative of low voter enthusiasm for both candidates.
It does not capture the full extent of online viewing, which has grown in popularity as traditional TV audiences decline.
Biden, already the oldest US president in history, faced only token opposition during the party's months-long nominating contest, and he has secured enough support to guarantee his spot as the Democratic nominee.
Former president Trump likewise overcame his intra-party challengers early in the year, setting the stage for a long and bitter general election fight.
Three columnists from the New York Times' progressive-leaning opinion section called on Biden to drop out of the race.
One Biden donor, who asked for anonymity, called his performance "disqualifying" and predicted that some Democrats would revisit calls for him to step aside.
That would give the party time to pick another nominee at its convention, which starts on August 19 - a potentially messy process that could pit Vice President Kamala Harris against governors and other office-holders whose names have been floated as possible replacements.
"It's not likely to happen," Biden campaign co-chair Mitch Landrieu said on CNN.
One campaign staffer, speaking on condition of anonymity, said they were frustrated by Biden's performance and hoped it would prompt top strategists to rethink their approach.
Former US president Barack Obama on Friday acknowledged Biden had a "bad" debate performance but he maintained his support for Biden.
"Bad debate nights happen. Trust me, I know," Obama said on X.
"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," Obama posted, adding: "Last night didn't change that."
The next Biden-Trump debate is scheduled to take place on September 10, hosted by US broadcaster ABC News.
There are no conversations about Biden stepping aside from his re-election bid and he plans to participate in the September debate, his campaign said on Friday.
with AP
