Six Takeaways From the First Presidential Debate

President Biden struggled through his first debate of the 2024 campaign against Donald J. Trump, meandering and mumbling through answers as the former president pressed his case for a second term with limited resistance from his rival.

They disagreed on abortion, inflation, climate change, foreign affairs and immigration. But the sharpest contrast was in their presentation.

Mr. Trump was confident and forceful, even as he let loose a stream of misleading attacks and falsehoods. Mr. Biden spoke with a hoarse and halting voice, closing his eyes occasionally to gather thoughts that sometimes couldn’t be corralled. Democratic anxiety rose by the minute. About halfway through, people close to Mr. Biden put out word that he had a cold.

Mr. Trump relentlessly hammered Mr. Biden on areas of vulnerability, sending exaggerations and embellishments — he was the “greatest” and his opponent the “worst” — flying unchecked through the audience-free CNN studio in Atlanta.

Here are six takeaways:

The debate exposed Biden’s biggest weakness.

Mr. Biden’s allies desperately hoped he could turn in a commanding performance to calm voters’ persistent concerns about his age.

That dream died within minutes.

A raspy Mr. Biden grasped to recall some specifics, and labored to articulate the statistics he could remember. In one early answer, he confused trillionaires with billionaires. Sometimes, he lost his train of thought entirely.

“We’re able to make every single solitary person … eligible for what I’ve been able to do with the, uh, with — with the Covid, or excuse me, with, dealing with, everything we have to do with, uh … Look … If … We finally beat Medicare,” he said.

It was bad enough that Vice President Kamala Harris went on CNN to clean up the performance.

“Yes, there was a slow start,” she said, “but it was a strong finish.”

Mr. Trump mostly avoided piling on to Mr. Biden’s weakest moments, letting him tie himself in verbal knots until the microphone cut the president off. “I really don’t know what he said at the end of that sentence,” Mr. Trump said at one point. “I don’t think he knows what he said either.”

Within half an hour after the debate began, some of the most influential Democrats in the country were privately texting notes of panic about the state of their candidate.

Questions about the 81-year-old president’s fitness were not eased. They were exacerbated.

Trump made his case largely unimpeded.

The Biden campaign demanded that the mics be muted during the debate because it was worried Mr. Trump would relentlessly interrupt, as he did in the first 2020 clash.

The precaution worked, but not to Mr. Biden’s benefit. Mr. Trump waited for his turn to speak and seemed to be enjoying himself.

In the weeks before the debate, Mr. Trump privately told advisers that he knew he had messed up and turned off voters with his argumentative behavior in 2020. His aides — who were hoping he wouldn’t fall back into that pattern — were delighted at what they saw from him on Thursday night.

The order of the topics helped.

It was nearly halfway into the debate before Mr. Trump’s recent felony conviction came up.

“The only person on this stage who is a convicted felon is the man I am looking at right now,” Mr. Biden said in a stronger moment.

As the evening wore on, Mr. Trump’s discipline slipped. He began making wilder claims, asserting that Mr. Biden was a “Manchurian candidate” who was “being paid by China” and “the whole country is exploding because of you.”

Regarding his own record, Mr. Trump’s statements were often fact-free and absurdly hyperbolic, including his remark, in a section about climate change, that “I had the best environmental numbers ever.”

The debate was more personal than policy-focused.

When they walked onstage, Mr. Biden and Mr. Trump never came close to shaking hands. Their mutual dislike shot through a night filled with invective and name-calling.

“You have the morals of an alley cat,” Mr. Biden said at one point.

The Biden team had wanted to showcase for the public two sharply contrasting visions, and to make the case that a second Trump term would be increasingly radical. But instead of a steady drumbeat about the stakes, the debate devolved to the point where the two men had a prolonged discussion about golf handicaps.

“He can’t hit a ball 50 yards,” Mr. Trump tutted.

His strongest issue is immigration, polling shows, while Mr. Biden’s is abortion. Yet at one point, Mr. Biden inexplicably appeared to try to pivot to immigration during an abortion answer.

Mr. Biden also attacked Mr. Trump for “having sex with a porn star” — a reference to his alleged affair and the hush-money payoff that led to his conviction on 34 felony counts for falsifying business records. Mr. Trump went after Mr. Biden’s son Hunter over his recent criminal conviction on federal gun charges — and made an oblique threat that if Mr. Biden loses, he could face charges from a future Trump administration.

At times, Mr. Biden squinted in disgust as he talked about Mr. Trump’s conduct, including the allegation, which Mr. Trump denied, that he once referred to dead American service members as “suckers and losers.”

In a role reversal, Mr. Trump at one point tried to chide Mr. Biden for unstatesmanlike behavior. “Let’s not act like children,” Mr. Trump scolded. Mr. Biden retorted, “You are a child.”

The moderators were hands (and mics) off.

Before the debate, Biden allies tried to pressure the CNN moderators, Jake Tapper and Dana Bash, to aggressively fact-check any false statements made by Mr. Trump. CNN leadership made clear that the moderators would facilitate the discussion but that any fact-checking would be left to the candidates.

On Thursday, Mr. Biden missed numerous opportunities to fact-check Mr. Trump, who often filled the vacuum with a torrent of exaggerations, falsehoods and attacks on Mr. Biden’s record and character. They often went unchecked by moderators, including the “Manchurian candidate” remark.

The Biden team largely imposed the terms of the debate on the Trump campaign, but it was Mr. Biden who appeared uncomfortable with the format.

If the first 2020 debate was defined by unintelligible cross-talk as Mr. Trump tried to bully his way into every answer, this one may be remembered for Mr. Biden’s stammering attempts to fill his allotted time.

Some of the most striking interventions by the moderators were simply to remind Mr. Biden that he had time remaining on his clock.

Trump still won’t accept the election results.

For the third consecutive presidential election, Mr. Trump is refusing to say that he will accept the results — a rejection of reality that culminated in the deadly violence at the Capitol on Jan. 6, 2021.

On Thursday night, Mr. Trump was twice asked if he would commit to accepting the results of the election, but he ducked the question. Pressed a third time, he said he would accept the outcome, but with a glaring “if.”

“If it’s a fair, and legal, and good election, absolutely,” he replied.

But Mr. Trump has already insisted baselessly this year that Democrats will cheat in November, suggesting that any election he does not win was probably rigged — a characterization he bases on his false and debunked claims of widespread voter fraud in 2020.

Mr. Trump brazenly tried to turn the Jan. 6 date to his advantage, rattling off favorable economic and energy statistics from that date to make his case that Americans were better off four years ago.

The split screen damaged Biden.

Mr. Biden’s struggles weren’t just apparent when he was speaking. For long intervals he stood silent, eyes darting, mouth agape.

CNN’s split screen of both candidates, shown throughout the debate, offered little reprieve for a president who kept trying to clear his throat in the early going. Mr. Trump, in contrast, grinned attentively and waited for his chance to attack.

“This guy’s three years younger, and a lot less competent,” Mr. Biden said in one attempted age-related counterpunch at Mr. Trump.

Mr. Biden also trotted out some familiar lines about “malarkey” but, like his voice, they sounded hollow at times.

Even if Mr. Biden did build some strength over the course of the evening, Frank Luntz, the focus-group guru, said that by the end of the evening, his gathering of undecided voters wanted the president to step aside.

“I think we did well,” Mr. Biden said during a stop at a Waffle House after the debate.

He had bet big that the earliest debate in general-election history would reshape the race in his favor. But now he must endure nearly two months of second-guessing before the Democratic National Convention, and more than 10 weeks until his next scheduled encounter with Mr. Trump.

Taylor Robinson contributed reporting from New York, and Michael Gold from Atlanta.