WASHINGTON — President Joe Biden worked forcefully Friday to quell Democratic anxieties over his unsteady showing in his debate with former President Donald Trump, as elected members of his party closed ranks around him in an effort to shut down talk of replacing him atop the ticket.

Biden’s halting delivery and meandering comments, particularly early in the debate, fueled concerns from even members of his own party that at age 81 he’s not up for the task of leading the country for another four years. It created a crisis moment for Biden’s campaign and his presidency, as members of his party flirted with potential replacements, and donors and supporters couldn’t contain their concern about his showing against Trump.

Biden appeared to acknowledge the criticism during a rally in Raleigh, North Carolina, saying “I don’t debate as well as I used to.” But he added, “I know how to do this job. I know how to get things done.” Speaking for 18 minutes, Biden appeared far more animated than he had the night before as he excoriated Trump for his “lies” and for waging a campaign aimed at “revenge and retribution.”

“The choice in this election is simple,” Biden said. “Donald Trump will destroy our democracy. I will defend it.”

He added, alluding to his candidacy, “When you get knocked down, you get back up.”

Even before the debate, Biden’s age had been a liability with voters, and Thursday night’s faceoff appeared to reinforce the public’s deep-seated concerns before perhaps the largest audience he will garner in the four months until Election Day.

Privately, his campaign worked to tamp down concerns and keep donors and surrogates on board. Democratic lawmakers on Friday acknowledged Biden’s poor showing, but tried to stop talk of replacing him as their standard-bearer, and instead shift the focus to Trump’s attacks and falsehoods.

“Well, the president didn’t have a good night, but neither did Donald Trump with lie after lie and his dark vision for America,” North Carolina Gov. Roy Cooper told The Associated Press on Friday, hours before he introduced the president in Raleigh. “We cannot send Donald Trump back to the White House. He’s an existential threat to our nation.”

Former President Barack Obama backed up his former vice president, posting on X that “Bad debate nights happen.” Alluding to his own poor showing in the first debate of his reelection campaign in 2012, Obama continued, “Trust me, I know. But this election is still a choice between someone who has fought for ordinary folks his entire life and someone who only cares about himself.”

He added: “Last night didn’t change that, and it’s why so much is at stake in November.”

House Democratic leader Hakeem Jeffries answered with a flat “no” when asked Friday if Biden should step aside.

Rep. Ritchie Torres, D-N.Y., allowed he “had to take a few more antidepressants than usual” after Biden’s debate showing.

But he added that “a Donald Trump presidency would cause me far greater discomfort than a Joe Biden debate performance.”

Biden’s campaign billed the Raleigh event as the largest-yet rally of his reelection bid in the state Trump carried by the narrowest margin in 2020. He then traveled to New York for a weekend of big-dollar fundraisers that his campaign now needs more than ever.

Biden’s campaign announced that it raised $14 million on debate day and the morning after, while Trump’s campaign said it raised more than $8 million from the start of the debate through the end of the night.

Vice President Kamala Harris, whom the Biden campaign sent out to defend his performance, tried to reassure Biden supporters at a rally in Las Vegas on Friday, saying, “This race will not be decided by one night in June.

“This race will be decided by you. By us,” she said. “Who sits in the White House next year will be determined by what we together do in these next 130 days.”

Biden campaign communications director Michael Tyler said there had been no internal conversations “whatsoever” about Biden stepping aside, though he, too, acknowledged that the president had a “bad night” on stage.