Democratic leaders called on President Biden and his campaign Wednesday to provide convincing evidence of a viable path to victory amid a steady tide of bad battleground state polling and growing concerns that he cannot defeat former president Donald Trump in November.

The calls came as top union leaders expressed grave concerns about his candidacy, more members of Congress and other Democrats called on him to step aside, and even members of Biden’s senior campaign staff began to exchange doubt about his prospects.

In a closed-door meeting Wednesday, some of the country’s union leaders — many of whom are strident backers of Biden — said Americans’ doubts about Biden’s ability to do the job were damaging his candidacy and repeatedly asked Biden campaign officials for their plan to defeat Trump, according to two people familiar with their comments, who like others for this story spoke on the condition of anonymity to share private comments. Two of the most outspoken leaders were Sara Nelson, the president of the Association of Flight Attendants, and Shawn Fain, the president of the United Auto Workers, two of Biden’s biggest labor allies.

In a statement later Wednesday, AFL-CIO leadership “unanimously voted to reaffirm its commitment” to Biden, saying, “No president has been more invested in helping workers than Joe Biden.”

Senior campaign staff have started to take a more pessimistic view of Biden’s chances, even as they continue to fan out in a full-court blitz to push the campaign forward and reassure allies of the president’s potential to rebound.

“Overwhelmingly a majority of senior campaign staff are despondent and don’t see a path,” said a Democratic strategist familiar with the conversations, who like many others for this story requested anonymity to speak frankly about internal deliberations. A second person familiar with the discussions did not dispute the description.

“We can either worry or we can work, and this team is doing the work that wins elections,” Biden campaign spokesman Kevin Munoz said in a statement.

Meanwhile, Democrats say the defections are likely to increase in coming days, with lawmakers and donors privately signaling that, by the end of the week, they may publicly call for Biden to drop out. They argue they do not want to embarrass Biden during the ongoing NATO summit in Washington while also giving him time to come to that conclusion on his own.

On Wednesday, Sen. Peter Welch of Vermont became the first Democratic senator to call on Biden to drop out, writing in a Washington Post op-ed that he should do so “for the good of the country” because of the danger posed by Trump. In addition, Rep. Pat Ryan (D-N.Y.), one of the party’s most vulnerable members, Rep. Earl Blumenauer (D-Ore.) and Antonio Delgado, the lieutenant governor of New York who formerly represented a swing district in Congress, also called on Biden to step aside.

At the first presidential debate with Trump on June 27, Biden was unable to complete sentences, often spoke haltingly and, at times, seemed confused about what question he was trying to answer. Democrats panicked over the performance, raising questions about his ability to serve another four years as president and renewing questions about the 81-year-old’s mental acuity.

Biden and his campaign continue to publicly maintain that he will not leave the race and that he is positioned to beat Trump in an election that will take place in 117 days. The Biden campaign told Democratic senators Wednesday that campaign chair Jen O’Malley Dillon, senior campaign adviser Mike Donilon and White House adviser Steve Ricchetti would meet Thursday for a briefing on the path forward. The Biden campaign said it conducted polling immediately after the debate that found no significant movement in the battleground states for Biden.

A Democratic senator, speaking on the condition of anonymity to offer a candid view, said that, if the campaign team tells senators that there has been little to no deterioration in the president’s position, “I don’t think anybody will believe it.” He added that senators will be looking for “convincing evidence that they can turn this thing around.”

Kate Bedingfield, the deputy campaign manager on Biden’s 2020 campaign and former White House communications director, gave voice to private frustrations in the party that the campaign has not yet offered an empirical case for Biden recovering from his debate setback and then gaining enough momentum to win.

“If they have data that supports the path to victory that they see, they should put it out there now and help people who badly want to beat Trump rally around it,” Bedingfield wrote on social media. “People want to see the path.”

Ron Klain, a longtime Biden adviser and former White House chief of staff, said there was unanimity among Biden’s team that he remains the best candidate to defeat Trump. “He wins in 2024 as he did in 2020 — because his personal values and character ultimately prevail against Trump,” Klain wrote in a text message.

Democrats have been privately sketching out possible scenarios and the timing of them, should Biden decide to leave the race, including Biden possibly endorsing the nomination of Vice President Harris. One Democratic strategist said time is of the essence: “Every iteration of this, earlier is better,” avoiding a “mad scramble” near or at the Democratic National Convention in August in Chicago.

Biden announced in a letter to Democratic allies Monday that he was “firmly committed to staying in this race, to running this race to the end, and to beating Donald Trump.” But former House speaker Nancy Pelosi (D-Calif.) appeared Wednesday on MSNBC’s Morning Joe — a show that Biden is known to watch regularly — where she described Biden’s continued candidacy as an open question.

“It’s up to the president to decide if he is going to run,” said Pelosi, who remains a member of the House since relinquishing her speakership. “We’re all encouraging him to make that decision. Because time is running short.”

House Democratic concerns are anchored in polling from before the debate that showed Biden already trailing Trump in districts that he won comfortably in 2020, with approval ratings in the low 4os, according to a person who has seen the data. In both House and Senate polls, down-ballot Democrats continue to outperform Biden in ballot tests.

An AARP poll released Tuesday — which was conducted by polling firms that work for the Biden and Trump campaigns — showed Biden trailing Trump in Wisconsin by six points in a five-way contest that included third-party candidates. Biden beat Trump in Wisconsin by less than a percentage point in 2020. Sen. Tammy Baldwin (D-Wis.) maintained a lead of three points over her Republican opponent, the businessman Eric Hovde, in the AARP poll.

“He is just a drag everywhere,” said another Democrat working on campaigns this cycle who has seen private polling across the country.

The campaign has since started another round of polling this week, though the results have not come back, said people familiar with the operation. Biden also announced he would sit down for a 9 p.m. interview Monday with NBC News anchor Lester Holt in Austin during the first night of the Republican nominating convention.

National public polls showed Trump with a slight lead before the debate — a sharp contrast to the lead of about four points Biden enjoyed over Trump at the same point in the 2020 campaign. Since the debate, national polls have showed a 2½-point average shift in Trump’s direction, according to a Washington Post average of polling.

Democrats are particularly concerned about Biden’s diminished status compared to the 2020 campaign. At this point in that cycle, he polled 9 points ahead of Trump in the RealClearPolitics average of polls. Biden won the national popular vote by 4½ points that November. Trump now leads the same average by more than 3 points.

Some Democrats have grown concerned in recent days about the pace of fundraising for Biden and the independent groups supporting his campaign, as high-dollar bundlers for the president have shown reluctance to work their networks or have refused to follow through with donations. The campaign was bringing in more than $3 million a day after the debate, according to people familiar with the internal numbers. Donations have since dropped off and campaign advisers are awaiting the Republican convention next week to see if enthusiasm returns.

The uncertainty among high-dollar donors about giving to independent groups has made it “hard to balance the checkbook,” said one fundraiser involved in the effort. “I think a lot of the large-dollar donors are going to move their funding to the House and the Senate. If Biden is going to stay in, he has got to pray that the small-dollar donors come through.”

On Wednesday, George Clooney, the Academy Award-winning actor and longtime Democratic donor, said Biden should drop out of the presidential race. Clooney — who co-hosted a fundraiser for Biden last month in Los Angeles — said the president “wasn’t even the Joe Biden of 2020” at that event.

“This isn’t only my opinion; this is the opinion of every senator and Congress member and governor that I’ve spoken with in private,” Clooney wrote in the New York Times. “Every single one, irrespective of what he or she is saying publicly.”

He continued: “The dam has broken. We can put our heads in the sand and pray for a miracle in November, or we can speak the truth.”

Lauren Kaori Gurley and Liz Goodwin contributed reporting.