WASHINGTON (AP) — President Joe Biden’s ability to run for reelection faced crucial tests Thursday as he prepared for questions at a highly anticipated press conference and his team met privately with skeptical senators on Capitol Hill. More House Democrats called for him to exit the race, and he made a notable flub ahead of the press conference.

In announcing a compact that would bring together NATO countries to support Ukraine, he referred to Ukraine’s leader Volodymyr Zelenskyy as “President Putin” to audible gasps in the room. He quickly returned to the microphone: “President Putin - he’s going to beat Putin,” Biden said.

Then he said: “I’m so focused on beating Putin,” in an effort to explain the gaffe.

“I’m better” Zelenskyy replied. “You’re a hell of a lot better,” Biden said back.

The Biden campaign laid out what it sees as its path to keeping the White House in a new memo, saying that winning the “blue wall” states of Wisconsin, Pennsylvania and Michigan is the “clearest pathway” to victory. And it declared no other Democrat would do better against Republican Donald Trump. Biden will head to Detroit on Friday.

But Thursday was pivotal. Biden must show skeptics during his whirlwind day with world leaders at NATO, and the evening press conference that he is up for another four years. Voters are watching, and elected officials are deciding whether to press for another choice.

It all comes as Democrats are facing an intractable problem. Top donors, supporters and key lawmakers are doubtful of Biden’s abilities to carry on his reelection bid after his recent debate performance, but the hard-fighting 81-year-old president refuses to give up as he prepares to take on Trump in a rematch.

“There is also no indication that anyone else would outperform the president vs. Trump,” said the memo from campaign chair Jen O’Malley Dillon and campaign manager Julie Chavez Rodriguez that was obtained by The Associated Press.

The memo sought to brush back “hypothetical polling of alternative nominees ” as unreliable and it said such surveys “do not take into account the negative media environment that any Democratic nominee will encounter.”

Meanwhile, the campaign has been quietly surveying voters on Vice President Kamala Harris to determine how she’s viewed among the electorate, according to two people with knowledge of the campaign who spoke to The Associated Press on condition of anonymity to talk about internal matters.

The people said the polling was not necessarily to show that she could be the nominee in Biden’s place, but rather to better understand how she’s viewed. The research came after Trump stepped up his attacks against Harris following the debate, according to another person familiar with the effort. The survey was first reported by The New York Times.

Senators, in particular, have been anxious to see Biden himself, and a midday huddle with his campaign team brought little clarity about the path forward.

As the day unfolded, Rep. Hillary Scholten, whose district is in the battleground state of Michigan, became the 10th House Democrat to call on Biden not to run for reelection. As the day went on more House Democrats joined including Rep. Brad Schneider of Illinois, Rep. Greg Stanton of Arizona and Rep. Ed Case of Hawaii, bringing the number of House Democrats to a dozen. In the Senate, only Democratic Sen. Peter Welch of Vermont, has so far called for Biden to step out of the race.

Scholten, a first-term Democrat, told The Detroit News that people can’t “unsee” Biden’s terrible debate performance and said in a statement that “it’s time to pass the torch.”

Top leaders in Congress have largely kept quiet as they meet privately with other lawmakers. But House Speaker Emerita Nancy Pelosi opened the door this week to a continued conversation about Biden’s political future when she publicly said “it’s up to the president” to decide what to do — even though Biden had already emphatically told Congress he was staying in the race.

House Democratic Leader Hakeem Jeffries said talks among lawmakers are “candid, comprehensive and clear-eyed” as they discuss the path ahead.

Jeffries, who supports Biden and the Democratic ticket, said House and Senate Democrats remain unified on the agenda ahead that includes growing the middle class, fighting for reproductive rights and pushing back against Trump and the far-right Project 2025 agenda.

While Biden has expressed confidence in his chances, his campaign on Thursday acknowledged he is behind, and a growing number of the president’s aides in the White House and the campaign privately harbor doubts that the president can turn things around.

But they’re taking their cues from Biden, expressing that he is in 100% unless and until he isn’t, and there appears to be no organized internal effort to persuade the president to step aside. His allies were well aware heading into the week there would be more calls for him to step down, and they were prepared for it.

Senate Majority Leader Chuck Schumer invited Biden’s team to meet with senators privately at the lunch hour to discuss concerns and the path forward, but some senators groused they would prefer to hear from the president himself.

The 90-minute conversation with the president’s team, which one person said included no new data, polling or game plan on how Biden would beat Trump, did not appear to change senators’ minds. The person was granted anonymity to discuss the closed door session.

The meeting was frank, angry at times and also somewhat painful, since many in the room know and love Biden, said one senator who requested anonymity to discuss the private briefing. Senators confronted the advisers over Biden’s performance at the debate and the effect on Senate races this year

One Democrat, Sen. Chris Murphy of Connecticut, said afterward, “My belief is that the president can win, but he’s got to be able to go out and answer voters’ concerns. He’s got to be able to talk to voters directly over the next few day.”

At the same time, influential senators are standing strongly with Biden, leaving the party at an impasse.

Sen. Bernie Sanders, the Vermont independent, told AP he thinks Biden “is going to win this election. I think he has a chance to win it big.”

Sanders said he has been publicly critical of the campaign, and said Biden needs to talk more about the future and his plans for the country. “As we come closer to Election Day, the choices are very clear,” he said.

The fresh emphasis on the “blue wall” states by the campaign, which has heavily invested in other battlegrounds such as Arizona, Nevada, North Carolina and Georgia, acknowledges that the path to defeating Trump in November is narrowing, even as the team insists the Sun Belt states are “not out of reach.”

Though senior campaign aides write in the memo that Biden could clinch 270 electoral votes in a number of ways, it also says those three states are critical and that is why Biden has prioritized the areas in his recent travels. including the upcoming trip to Michigan. He went to Madison, Wisconsin; Philadelphia and Harrisburg, Pennsylvania over the weekend.

It acknowledges “real” movement in the race, but argues that it was not a “sea change.”

Campaign leaders say they want to continue touting Biden’s achievements in office, drawing a contrast with Trump and his policies, and redoubling their grassroots efforts to engage voters — which were their goals anyway before the disastrous June 27 debate that left in question Biden’s cognitive capabilities and fitness to serve. Their internal research suggests that voters will make their decisions based on policies and issues, rather than Biden’s age, O’Malley Dillon and Rodriguez contend.

Polls conducted after the debate have largely agreed that Democrats nationwide have doubts about Biden’s ability to lead the ticket in November.

__ Associated Press writers Michael Balsamo, Colleen Long, Mary Clare Jalonick, Kevin Freking, Farnoush Amiri and Linley Sanders contributed to this report.