ATLANTA (AP) — A raspy and sometimes halting President Joe Biden repeatedly sought to confront Donald Trump in their first debate ahead of the November election, as his Republican rival countered Biden’s criticism by leaning into falsehoods about the economy, illegal immigration and his role in the Jan. 6, 2021, Capitol insurrection.

Biden’s uneven performance crystallized the concerns of many Americans that, at age 81, he is too old to serve as president. It sparked a fresh round of calls for the Democrat to step aside.

Meanwhile, the 78-year-old Trump’s rhetoric offered Americans an unwelcome reminder of the bombast he launched daily during his tumultuous four years in office, as he struggles to win over skeptical voters. He declined to clearly state he would accept the results of the November election, four years after he promoted conspiracy theories about his loss that culminated in the Jan. 6 insurrection.

Biden repeatedly tore into Trump in personal terms in an apparent effort to provoke him, bringing up everything from the former president’s recent felony conviction to his alleged insult of World War I veterans to his weight and golf game. But his halting delivery from the beginning of the debate drew the most attention immediately afterward. Trump’s allies immediately declared victory while prominent Democrats publicly questioned whether Biden could move forward.

“I think there was a sense of shock, actually, of how he came out at the beginning of this debate, how his voice sounded. He seemed a little disoriented. He did get stronger as the debate went on but by that time, I think the panic had set in,” said David Axelrod, a longtime advisor to former President Barack Obama, said on CNN immediately after. “And I think you’re going to hear discussions that, I don’t know will lead to anything, but there are going to be discussions about whether he should continue.”

Said Van Jones, another Democratic strategist, on CNN: “He did not do well at all.”

David Plouffe, Obama’s former campaign manager, described the debate on MSNBC as a “DEFCON1” moment for Democrats.

Biden began the night with a raspy voice and a halting delivery as he tried to defend his economic record and criticize Trump. A person familiar with the matter said Biden was suffering from a cold during the debate, adding that he tested negative for COVID-19.

Biden appeared to lose his train of thought while giving one answer, drifting from an answer on tax policy to health policy, at one point using the word “COVID,” and then saying, “excuse me, with, dealing with,” and he trailed off again.

“Look, we finally beat Medicare,” Biden said, as his time ran out on his answer.

Biden began to give clearer answers as the debate progressed, still with a rasp, and attacked Trump’s record on issues like fighting climate change.

“The only existential threat to humanity is climate change, and he didn’t do a damn thing about it,” he said.

The current president and his predecessor hadn’t spoken since their last debate weeks before the 2020 presidential election. Trump skipped Biden’s inauguration after leading an unprecedented and unsuccessful effort to overturn his loss that culminated in the Capitol riot by his supporters.

Trump equivocated on whether he would accept the results of the November election, saying he would accept them if the vote was “fair” and “legal,” repeating his baseless claims of widespread fraud and misconduct in his 2020 loss to Biden that he still denies.

Pressed on his actions on Jan. 6, 2021, Trump was unapologetic.

“On Jan. 6, we were respected all over the world, all over the world we were respected. And then he comes in and we’re now laughed at,” Trump said.

After he was prompted by a moderator to answer whether he violated his oath of office that day by rallying his supporters seeking to block the certification of Biden’s Electoral College victory and not acting for hours to call them off as they raided the Capitol, Trump sought to blame then-House Speaker Nancy Pelosi.

Biden said Trump encouraged the supporters to go to the Capitol and sat in the White House without taking action as they fought with police officers.

“He didn’t do a damn thing and these people should be in jail,” Biden said. “They should be the ones that are being held accountable. And he wants to let them all out. And now he says that if he loses again, such a whiner that he is, that this could be a ‘bloodbath’?”

Trump then defended the people convicted and imprisoned for their role in the insurrection, saying to Biden, “What they’ve done to some people that are so innocent, you ought to be ashamed of yourself.”

Trump and Biden entered the night facing stiff headwinds, including a public weary of the tumult of partisan politics and broadly dissatisfied with both, according to polling. But the debate was highlighting how they have sharply different visions on virtually every core issue — abortion, the economy and foreign policy — and deep hostility toward each other.

Their personal animus quickly came to the surface. Biden got personal in evoking his son, Beau, who served in Iraq before dying of brain cancer. The president criticized Trump for reportedly calling Americans killed in battle “suckers and losers.” Biden told Trump, “My son was not a loser, was not a sucker. You’re the sucker. You’re the loser.”

Trump said he never said that — a line attributed to Trump by his former chief of staff — and slammed Biden for the chaotic withdrawal of U.S. forces from Afghanistan, calling it “the most embarrassing day in the history of our country’s life.”

Trump himself agreed to the withdrawal with the Taliban a year before he left office.

Biden directly mentioned Trump’s conviction in the New York hush money trial, saying, “You have the morals of an alley cat,” and referencing the allegations in the case that Trump had sex with a porn actress.

Trump retorted that Biden could face criminal charges “when he leaves office,” evoking his familiar threats of retribution. Though there is no evidence of any wrongdoing, Trump said, “Joe could be a convicted felon with all the things that he’s done.”

Pressed to defend rising inflation since he took office, Biden pinned it on the situation he inherited from Trump amid the COVID-19 pandemic.

Biden said that when Trump left office, “things were in chaos.” Trump disagreed, declaring that during his term in the White House, “Everything was rocking good.”

By the time Trump left office, America was still grappling with the pandemic and during his final hours in office, the death toll eclipsed 400,000. The virus continued to ravage the country and the death toll hit 1 million over a year later.

Trump repeatedly insisted that the three conservative justices he appointed to the Supreme Court helped overturn the landmark Roe v. Wade decision and returned the issue of abortion restrictions to individual states, which is what “everybody wanted.” Biden countered that abortion access was settled for 50 years and that Trump was making it harder for women in large swaths of the country to get access to basic health care.

At one point, Trump defended his record on foreign policy and blamed Biden for the conflicts in Ukraine and Gaza, suggesting the conflicts broke out when the aggressors felt free to attack because they perceived Biden as weak.

“This place, the whole world, is blowing up under him,” Trump said.

“I never heard so much malarkey in my whole life,” Biden retorted.

Trump was asked what he would do to make childcare more affordable. He used his answer to instead boast about how many people he fired during his term, including former FBI Director James Comey and criticized Biden for not firing people from his administration.

Trump has promised sweeping plans to remake the U.S. government if he returns to the White House and Biden argues that his opponent would pose an existential threat to the nation’s democracy.

Aiming to avoid a repeat of their chaotic 2020 matchups, Biden insisted — and Trump agreed — to hold the debate without an audience and to allow the network to mute the candidates’ microphones when it is not their turn to speak. The debate’s two commercial breaks offered another departure from modern practice, while the candidates have agreed not to consult staff or others while the cameras are off.

Both men abided by the rules and didn’t speak out of turn. Near the end, Biden also appeared to question Trump’s weight — leading Trump to respond while his mic was muted, making his answer partly inaudible — and the two squabbled about their golf handicaps.

“Let’s not act like children,” Trump replied.

Trump walked straight off the stage alone, after the debate. Biden was joined by his wife Jill, who watched from a green room. They hugged and kissed and she held his hand and seemed to assist him down the stairs as they approached Bash and Tapper to greet the moderators before leaving.

Heading out of the debate, both Biden and Trump will travel to states they hope to swing their way this fall. Trump is heading to Virginia, a onetime battleground that has shifted toward Democrats in recent years.

Biden is set to jet off to North Carolina, where he is expected to hold the largest-yet rally of his campaign in a state Trump narrowly carried in 2020.