How will this end? It’s all up to Biden, allies say.

President Biden’s guiding principle for jumping into the 2020 presidential race was that he was the only person who could beat then-President Donald Trump. Now, if Biden is to jump out of the race, he - and he alone - will have to decide he is no longer that person, according to allies and aides.

Following a faltering, confused debate performance facing off against Trump last week, Democrats inside and outside the administration are privately grappling with what would need to happen for Biden to exit the presidential contest just six weeks before the party convention and four months before the election.

With Biden and his aides vowing that he has no intention of exiting the race - he told campaign staff on Wednesday that “no one is pushing me out” and “I’m not leaving” - Democratic allies, strategists and elected officials are in growing agreement about the conditions required for Biden to step aside.

The polling would need to further plummet. Elected Democrats would need to desert him in large numbers. And donor money would need to show clear signs of drying up.

Then, a group of Democratic leaders - figures such as Senate Majority Leader Charles E. Schumer (N.Y.), Rep. James E. Clyburn (S.C.) or former House speaker Nancy Pelosi (Calif.) - could privately tell Biden that not only is he going to lose but remaining on the ticket is also going to cost them the House and the Senate.

“That cuts at his core: Not only am I going to lose, but I’m going to lose the Senate and the House,” said a Democratic strategist in regular conversations with congressional lawmakers and aides, who like many in this story spoke on the condition of anonymity to offer a candid assessment.

Any pitch for dropping out needs to appeal to Biden’s sense of dignity, honor and public service, according to allies who have worked with Biden over the years. Several suggested almost identical language - stressing his “historic” and “consequential” presidency and likening him to former president Lyndon B. Johnson in terms of the scale of meaningful legislation he has helped usher into law.

But now, they would continue, the country has changed, Biden has changed, and it’s time to move on.

“It is always key to know when to walk away on our own two feet and volition,” said one Democratic official, who thinks Biden will ultimately bow out.

A former Democratic Senate aide now in regular contact with Democratic donors and elected officials was more blunt: “He’s going to become a ‘Scarlet B’ around candidates’ necks, and it’s not going to be a pleasant experience, and it’s going to be humiliating and demeaning for someone like him who doesn’t deserve that and deserves a more dignified exit based on their record.”

The other part of the pitch to Biden, these people say, is to remind him that he ran to stop Trump and the existential threat he believed Trump posed to American democracy. If Biden loses and drags the House and Senate down with him, not only will Trump return to the White House - but there also will be no bulwark against him and what Democrats believe are his dangerous policies.

Losing the Senate, for instance, means there would be no check on Trump appointing a slew of MAGA-minded judges to lifetime appointments.

“The president has been around politics a long time, and I believe very much that he sees this as an existential fight with Trump, and if he sees numbers that suggest to him that this isn’t a winnable race, my guess is he’ll act on them,” said David Axelrod, a top aide under former president Barack Obama.

Still, allies say Biden must reach the decision himself, though key Democrats also have a role to play. Biden has long valued above nearly all else the opinions of fellow elected officials - politicians who, like him, have had to win races and answer to voters.

In addition to Democratic leaders such as Schumer and House Minority Leader Hakeem Jeffries (N.Y.), Democrats stressed the importance of the entire party apparatus making the case to him - a group that besides members of Congress should include governors and “formers,” such as former presidents Obama and Bill Clinton.

Obama, however, is not necessarily a perfect messenger. A former Obama official conceded that the 44th president would play a complicated role in any final decisions, given his perceived preference for Hillary Clinton over Biden in 2016.

For years, Biden complained about being pushed aside, believing he would have defeated Trump then, and his staff griped about the overall lack of respect they sometimes felt from Obama’s staff when Biden served as his vice president.

Obama and Biden have spoken privately since the debate, and the former president offered to be a sounding board for the president as he charts his path forward, people familiar with the call said.

Biden’s first run for president, in 1987, ended in scandal after he was caught plagiarizing a British politician. Biden’s family encouraged him to stay in the race, but the then-senator decided to drop out because he worried the scandal would overshadow his ability to oversee the hearings for Robert Bork, Ronald Reagan’s nominee for the Supreme Court.

“It seems to me I have a choice,” Biden said that year as he dropped out of the presidential race. “I have to choose between running for president and doing my job to keep the Supreme Court from moving in a direction that I believe to be truly harmful.”

The party’s reaction to Biden’s faltering performance at last week’s debate has been one of widespread panic, dramatically changing the parameters of the presidential race. In the standoff with Trump, Biden struggled to parry attacks, rambled with some answers, stared blankly while Trump spoke and at times seemed confused about the issues he was discussing.

In the following days, the message from Biden’s orbit to alarmed allies was to stay calm. The Fourth of July holiday weekend was coming up. No one could accurately assess the debate fallout until the end of July, they argued.

Now, however, that timetable seems to have accelerated. In private, Biden went from offering his public justifications - it was one bad night, he was exhausted from recent foreign travel - to accepting that the situation is politically grim and discussing with allies ways he might be able to prove his readiness for a second term.

Karine Jean-Pierre, the White House press secretary, said on Wednesday that Biden is “absolutely not” dropping out, and Biden advisers say the president remains the only option to defeating Trump. They argue that public polling shows that no other Democrat is significantly better positioned or could stand up a campaign with only four months to go.

Biden is slated to do some public events - a Friday rally in Madison, Wis., and a scheduled interview the same day with ABC’s George Stephanopoulos - before returning to Washington to host next week’s NATO summit.

“Clearly it’s taken time to set in exactly the gravity of the situation and the hole that’s been dug,” said Tim Ryan, a former Democratic congressman from Ohio who has publicly called for Biden to step aside and for Vice President Harris to replace him as the Democratic nominee.

A growing number of Democrats say they see no path forward for Biden, and no way for Democrats to keep the White House if he doesn’t give up his spot at the top of the ticket. Others say they largely agree with that sentiment but think Biden - who has run for the presidency three times before now - is unlikely to relinquish the Oval Office he fought so hard to attain.

A New York Times and Siena College poll released Wednesday showed that Biden trails Trump 43 percent to 49 percent among likely voters nationally - marking a three-point swing toward Trump from the previous, pre-debate week. A Wall Street Journal poll after the debate also found Biden trailing Trump by six points - 42 percent to 48 percent - compared with February, when Trump held a two-point lead.

Across eight national polls tracked by The Washington Post, Biden trails Trump by an average of three percentage points, compared with a one-point average deficit for Biden in the last pre-debate surveys by those same polling firms.

But the campaign’s internal polling is not so stark, people familiar with the data said.

One reason that lawmakers such as Clyburn and Pelosi began giving more forceful interviews on television this week is because Democrats fear that none of the angst, frustration and alarm is penetrating Biden’s insular inner circle, and they wanted him to hear the message, even just publicly, one Democratic House member said.

Speaking Tuesday on MSNBC, Pelosi said it was a “legitimate question” to ask whether Biden’s mediocre debate performance was “an episode or is this a condition,” and encouraged the president to prove to the public that he is up not just for the job of president but for defeating Trump in November.

A person familiar with Pelosi’s thinking said she was not issuing a “warning shot” with her comments but trying to signal that the president’s low-key strategy was not working and needed to change. She has also communicated this message privately to people in Biden’s orbit, this person said.

Initially, there was some hope that Biden’s family would urge him to step aside, but that now seems increasingly unlikely. Biden’s wife, Jill, and his son, Hunter, are still adamant that he remain in the race, according to people familiar with their conversations.

Biden’s inner circle has shown no public signs of urging him to find an off-ramp. The former Senate aide said that if the polling becomes unambiguously catastrophic, Biden might be persuaded “the hard way” - in which “other Democratic elected officials come to him in private, and also in public, and call on him to resign, and distance themselves from him and say that by being in the race, you are making it far more likely that Trump will win.”

One thing holding up more Democratic lawmakers and leaders from publicly calling on Biden to drop out is their deep uncertainty over how disruptive such a move would be. Some are not convinced that Harris would fare any better against Trump but also do not see a clear path to bypass her - the nation’s first female, Black and Indian American vice president - without alienating huge swaths of the Democratic base.

Yet Ryan said that in his conversations with members of Congress, he has not heard particular consternation about Harris.

“They believe that the worst-case scenario, the most risky scenario, is the president running again,” Ryan said. “And while a convention may be risky, or Kamala Harris may be risky, they’re not nearly as risky as the status quo.”

Leigh Ann Caldwell and Paul Kane contributed to this report.