US President Joe Biden heads back out on the campaign trail Sunday, desperate to salvage his re-election bid as senior Democrats meet to discuss growing calls that he quit the White House race.
The 81-year-old Democrat kicks off a grueling week with two campaign rallies in the battleground state of Pennsylvania, before hosting the NATO leaders' summit in Washington.
He will do so under an increasingly unforgiving spotlight, as pressure mounts for him to drop out after his disastrous debate against Donald Trump last month ignited panic over his age and fitness to serve another four years.
Biden has remained defiant, unequivocally declaring - at a rally, to reporters and on social media - that he is fit to serve, the only one who can defeat Trump, and staying in the race.
"I beat Trump in 2020. I'm going to beat him again in 2024," his campaign social media account posted Saturday.
But a televised interview with ABC News on Friday has failed to quell concerns. His next major test in the public eye will be a press conference scheduled for Thursday, during the NATO summit.
So far, five Democratic lawmakers have called on Biden to drop out, with the drumbeat of dissent slowly rising.
The House minority leader, Hakeem Jeffries, has scheduled a virtual meeting of senior Democrat representatives for Sunday to discuss the best way forward, and Democrat Senator Mark Warner is reportedly working to convene a similar forum in the upper chamber.
First Lady Jill Biden, who - according to some US media reports - is urging her husband to stay in the race, is scheduled to campaign in Georgia, Florida and North Carolina on Monday.
But after Sunday's rallies in Philadelphia and Harrisburg, the president will have to step away from the campaign for the NATO summit beginning Tuesday.
Here, too, he will find himself having to reassure allies at a time when many European countries fear a Trump victory in November.
The 78-year-old Republican has long criticized NATO as an unfair burden on the United States, voiced admiration for Russian strongman Vladimir Putin, and insisted he could bring about a quick end to the fighting in Ukraine, where the Russian invasion is now in its third year.
'Lord Almighty'
For now, Democrat heavyweights are largely keeping a lid on any simmering discontent with their leader - at least in public.
But with election day just four months away, any move to replace Biden as the nominee would need to be made sooner rather than later, and the party will be scrutinized for any signs of more open rebellion.
Meanwhile, for Biden and his campaign team, the strategy seems to be to ride it out.
The campaign has unveiled an intense battle plan for July, including an avalanche of TV spots and trips to all the key states.
That includes a visit to the southwest of the country during the Republican convention from July 15-18, at which Trump is set to be anointed the party's official presidential nominee.
In what had been billed as a make-or-break interview with ABC News on Friday, Biden flatly dismissed the falling poll numbers and concerns over his mental and physical fitness triggered by his dismal June 27 performance against Trump.
He blamed a severe cold for the debate debacle and insisted it was just a "bad night" rather than evidence of increasing frailty and cognitive decline.
The sit-down has not soothed the concerns of critics who say that - away from a teleprompter - Biden can struggle to communicate.
Some of his answers were tentative, meandering and difficult to follow, even as he sought to deflect questions about his mental acuity and dismissed the notion that his party would consider replacing him.
"If the Lord Almighty came down and said, 'Joe, get out of the race,' I'd get out of the race," he said.
"But the Lord Almighty is not coming down."