President Biden hoped to build fresh momentum for his re-election bid by agreeing to debate two months before he is formally nominated. Instead, his halting and disjointed performance on Thursday night prompted a wave of panic among Democrats and reopened discussion of whether he should be the nominee at all.
Over the course of 90 minutes, a raspy-voiced Mr. Biden struggled to deliver his lines and counter a sharp though deeply dishonest former President Donald J. Trump, raising doubts about the incumbent president’s ability to wage a vigorous and competitive campaign four months before the election. Rather than dispel concerns about his age, Mr. Biden, 81, made it the central issue.
Democrats who have defended the president for months against his doubters — including members of his own administration — traded frenzied phone calls and text messages within minutes of the start of the debate as it became clear that Mr. Biden was not at his sharpest. Some took to social media to express shock at his troubles, while others privately discussed among themselves what it would mean for the party and whether it was too late to persuade the president to step aside in favor of a younger candidate.
“Biden is about to face a crescendo of calls to step aside,” said a veteran Democratic strategist who has staunchly backed Mr. Biden publicly. “Joe had a deep well of affection among Democrats. It has run dry.”
“Parties exist to win,” this Democrat continued. “The man on the stage with Trump cannot win. The fear of Trump stifled criticism of Biden. Now that same fear is going to fuel calls for him to step down.”
Mr. Biden’s goal in accepting a general election debate earlier than ever held in presidential history was to recalibrate the contest as a choice between him and a felon who tried to overturn an election and would destroy American democracy if given the power of the presidency again. Mr. Biden left the CNN studio in Atlanta instead facing a referendum on himself and his capacity that will reverberate for days if not longer.
Mr. Trump, 78, appeared to coast through the debate with little trouble, even as he rattled off one falsehood after another without being effectively challenged. He appeared confident while avoiding the same excessively overbearing demeanor that damaged him during his first debate with Mr. Biden in 2020, seemingly content to let his opponent stew in his own difficulties.
“Guys, the Dems should nominate someone else — before it’s too late,” Andrew Yang, who ran against Mr. Biden for the Democratic nomination in 2020, wrote on social media before the debate had ended, adding a hashtag #swapJoeout.
Van Jones, a former White House aide to President Barack Obama and a leading liberal voice, predicted there would be a renewed discussion of that. “There’s a lot of people who are going to want to see him consider taking a different course now,” Mr. Jones said on CNN after the debate.
Online discussion was filled with similar assessments within the first half-hour of the showdown. “Sorry, I’m voting for President Biden but this is a disaster so far,” wrote Mike Murphy, an anti-Trump Republican. He added: “On a 1 to 10 point scale — if this continues — the panic explosion inside the Democratic Party will hit 28 tmmrw.”
Alyssa Farah Griffin, a former White House aide to Mr. Trump who broke with him, said, “It’s worse than I believe most people imagined.”
Mr. Biden’s advisers have long rejected any discussion of him dropping out, dismissing such talk as unjustified nervousness even as he has trailed Mr. Trump in battleground states needed for victory this fall. Biden aides and allies have repeatedly challenged the polls and pointed out that predictions of Democratic defeats in recent elections have been overblown.
No incumbent president has dropped out of the race so late in the campaign cycle, and there is little consensus about what would happen if he were to. Democrats on Thursday night were imagining scenarios that would require party elders like Senator Chuck Schumer of New York, former Speaker Nancy Pelosi of California and Representative James E. Clyburn of South Carolina to intervene with the president, although there was no indication that any of them would agree to do so.
Other Democrats said they feared that it was too late and that Mr. Biden would not listen to anyone other than perhaps his wife, Jill Biden, who has strongly supported another run. The president’s team ended the evening knowing that the task of the next few days would be to quiet such talk and rally the party behind their besieged leader.