To prevent leaks, their cellphones were collected at the door on Tuesday.
Congressional Democrats on Tuesday gathered for a consequential day of closed-door meetings where the focus is expected to be largely on President Joe Biden's viability as a candidate and the path for the party going forward.
House Democrats huddled Tuesday morning at the Democratic National Committee headquarters just steps from the U.S. Capitol.
In a sign of how sensitive the conversation was expected to be, lawmakers' cellphones were collected at the door, presumably to prevent real-time leaks about the private discussion.
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Members were asked by reporters if they still support Biden's reelection bid as they entered the building. Many signaled they did, including former House Majority Leader Steny Hoyer, Rep. Maxine Waters, Rep. Bennie Thompson and others.
Rep. Jerry Nadler, who privately said on a call Sunday he wanted Biden to step aside, appears to have changed his mind. Nadler told reporters that Biden "made it very clear he is running. I am fully supportive of him. I plan to campaign for him."
Several Democrats denounced Project 2025, a sweeping plan to overhaul the federal government proposed by a conservative group closely aligned with former President Donald Trump, as they made their way inside.
But members were tight-lipped as they exited about details of their discussion.
Senate Democrats are set to hold their own conference meeting on Tuesday, which would mark the first time the senators have met since Biden's poor debate performance against Donald Trump in late June that triggered panic among some in the party about his fitness to carry out the 2024 campaign and serve another four years.
The meetings come at a pivotal moment for Biden, as calls for him to step aside from the race mounted this past week even after he and the White House ramped up outreach to anxious Democrats as it went into damage control mode.
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Biden defiantly pushed back on critics on Monday, first in a blunt letter to Democrats saying it's time for such hand-wringing to end and then in a call to MSNBC's "Morning Joe" in which he railed against "elites" challenging his capabilities.
"The bottom line is, we're not going anywhere. I am not going anywhere!" Biden told MSNBC anchors Joe Scarborough and Mika Brzezinski.
The question now is will Democrats fall in line behind Biden or will questions about his candidacy continue to grow with the Democratic National Convention just weeks away.
So far, six Democrats have publicly said they do not support Biden as the nominee: Reps. Adam Smith, Angie Craig, Seth Moulton, Lloyd Doggett, Mike Quigley and Raul Grijalva.
"He just has to step down because he can't win. My colleagues need to recognize that a dismissive letter is not going to change any minds," Quigley said as he entered the caucus meeting on Monday.
Several other senior House Democrats had privately told House Minority Leader Hakeem Jeffries on Sunday that they're calling on Biden to exit the race, according to several sources with knowledge of the discussion. Jeffries did not express a position and said he would engage with the caucus throughout the week, according to one person on the call.
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Biden on Monday met with Congressional Black Caucus virtually, sources told ABC News. Black voters helped propel Biden to the White House in 2020 and are a critical voting bloc again in 2024. So far, no member of the Congressional Black Caucus has called on the president to step aside.
"I need you; I'm not going to disappoint you, I promise you," the president told the members, one of the call participants said.
No Democratic senator has publicly called on Biden to withdraw from the race, but concerns have been raised by Sen. Mark Warner. Warner, who chairs the influential Senate Intelligence Committee, tried to assemble a group of Senate Democrats to discuss Biden's path forward as early as Monday but the meeting didn't take place.
Warner, in a statement on Tuesday, said "now is the time for conversations about the strongest path forward" given what is at stake in the November election.
"As these conversations continue, I believe it is incumbent upon the President to more aggressively make his case to the American people, and to hear directly from a broader group of voices about how to best prevent Trump's lawlessness from returning to the White House," Warner said.
Montana Sen. Jon Tester, one of the most vulnerable Senate Democrats up this cycle, similarly said that Biden needs to "prove" to him and voters that he's up to the job.
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Meanwhile, Sen. Joe Manchin, who became an independent earlier this year but still caucuses with Democrats, urged his colleagues to see how the coming days unfold before determining Biden's future.
"The president has set a course of where he wants to go," Manchin told ABC News Senior Congressional Correspondent Rachel Scott. "I think he has earned that right and he has a heck of a legacy right now with all the service he has. And just give it time."
Manchin told reporters he believes the race is "winnable" for Biden.
"I have always said Trump is a threat to democracy," he said. "You can't call the race now. I mean, this is ridiculous. It's early for people to get so excited. The bottom line is just wait until this week."
This week, Biden will also be tested on the world stage as he hosts dozens of leaders in Washington for the 2024 NATO summit amid reports claiming U.S. allies have privately questioned his ability to lead.
ABC News' Lauren Peller, John Parkinson and Arthur Jones contributed to this report.