President Joe Biden’s support among elected Democrats appeared to be fraying as senior members of Congress openly raised doubts about his faltering re-election bid.
The 81-year-old Mr Biden failed in his attempts to explain away his disastrous debate performance against Donald Trump, 78, when he told an ABC interviewer on Friday that only “the Lord almighty” could persuade him to drop out of the White House race.
He sought to project vigour on a campaign stop in Pennsylvania.
But tension over the prospect of Mr Trump returning to power in November mounted as Sir Keir Starmer was set to head to Washington on Tuesday for his first international meeting as Prime Minister, a Nato summit.
Connecticut Senator Chris Murphy said the president faces a “really critical week”.
“And let’s just be honest: I think there are still questions out there in the minds of many voters,” he told CNN.
“And I think the president needs to make some moves this week to put himself out there in a position to answer those questions.
“And if he can’t do that, then, of course, he’s going to have to make a decision about what’s best for the country and what’s best for the party,” the Democrat said.
The Nato summit is focussed on Russia's war with Ukraine, and Mr Trump is unabashed in calling for a peace deal despite Vladimir Putin’s seizure of Ukrainian territory, after previously casting doubt on US support for Nato itself.
All eyes will be on Mr Biden, the oldest president yet, to judge his mental and physical stamina after he blamed a cold and fatigue for his poor showing in the first TV debate with Mr Trump - who has seized on it to argue that a rival only three years his senior is too old and infirm to serve.
The Washington gathering is unfolding a week before Republicans gather in Milwaukee to formally nominate Mr Trump, who during the debate simply shrugged when Mr Biden asked him if he would "stay in Nato or you're going to pull out of Nato?"
With Congress resuming after a week-long recess, Democrats were also re-convening in Washington, and increasingly breaking ranks to express their own doubts about the president.
Hakeem Jeffries, the top ranking Democrat in the House of Representatives, organised a virtual call of some 15 top House committee members.
At least four Representatives - Jerrold Nadler of New York, Jim Himes of Connecticut, Adam Smith of Washington state and Mark Takano of California — privately said Mr Biden should step aside, sources told US media.
A fifth Democratic Representative, Jim Himes of Connecticut, expressed uncertainty about Mr Biden while a sixth, Susan Wild of Pennsylvania, said afterwards that she had “expressed the same concerns that Americans across the country are grappling with, about President Biden’s electability”.
But others spoke out for the president.
Richard Neal of Massachusetts, the top Democrat on the tax-writing Ways and Means Committee, said that Mr Biden beat Mr Trump in 2020 and "he'll do it again in November”.
Democratic Senators were expected to discuss the White House race at their weekly lunch on Tuesday, as the party gears up for its own nominating convention next month.
