5 lessons from the remarkable presidential debate between Biden and Trump

President Joe Biden delivered a tentative performance in the debate with former President Donald Trump on Thursday – raising new questions about his future – at an event widely seen as a test of the two candidates’ fitness for the office.

The two debated a policy agenda on stage in Atlanta, but little new was achieved. The focus was instead on how the 81-year-old president and his 78-year-old predecessor would handle another four years in the Oval Office – while Democrats worried about Biden’s performance.

Here are five takeaways from Thursday night’s clash.

Biden with a slow start

Biden came on stage with a croaking voice and stumbled through some of his answers early on.

For example, when asked about national debt, he replied that there were “thousands of trillionaires,” but then corrected himself.

His biggest slip-up, however, came about 12 minutes into the debate, when he paused for six seconds after talking about how the country could have spent the money raised by taxes on wealthy Americans if Trump had not passed tax cuts during his term in office.

“We could help make sure all the things we need to get done: child care, elder care, we could make sure we continue to strengthen our health care system. We could make sure that every single person is entitled to what I was able to do with – excuse me, with COVID – by taking care of everything we need to do, look… we finally defeated Medicare,” Biden said, seeming to lose his thread at the end of his answer.

The moment highlighted a central theme of the debate – Biden’s intellectual acuity and fitness for office – and sparked cheers among Republicans.

“Game over!!!” Bryan Lanza, a former Trump campaign aide who is still in touch with the former president’s current team, texted ABC News.

The Democrats also struck a negative tone.

“A few words the Biden team should look up: espresso; and honey and lemon for the throat,” said a senior Democratic strategist.

As the debate progressed, Biden seemed to gain momentum, calling Trump a “convicted felon” and conflating the two’s criminal records, but the president’s performance was less forceful than that of his opponent.

Biden’s team turns its performance

Biden’s team quickly worked to whitewash his performance, apparently realizing that he probably hadn’t performed the way Democrats had hoped.

The campaign said the president had a cold but tested negative for COVID-19, but it’s unclear why that news wasn’t announced earlier. The campaign told ABC News’ Mary Bruce they were fine, but acknowledged he had a slow start.

“Tonight, President Biden presented a positive and successful vision for America’s future – a vision in which every American has a fair chance to achieve the American dream, in which every one of our rights is protected, and in which our president fights to strengthen our democracy – not destroy it,” said Biden’s campaign manager Jen O’Malley Dillon.

Biden’s allies reiterated their support for the president in the past, acknowledging that the evening likely did not go as planned but that the president would remain the nominee.

“I don’t care, I’m sticking with Joe Biden,” former Democratic National Committee chair Donna Brazile said on ABC News Live.

Trump (mostly) keeps a cool head

Investigators were keeping an eye on which version of Trump would appear on stage on Thursday: the bully who repeatedly interrupted Biden during their first debate in 2020? Or would he be a more staid presence who would be interpreted as presidential?

By and large, the latter was a more accurate description of Trump’s performance.

Trump did resort to his more bombastic rhetoric, exaggerating the economic situation during his term and the number of border crossings and crimes under Biden, saying Biden “could be a convicted felon” and accusing the president of “going after his political opponent because he cannot win fairly and honestly.”

But he did not focus his arguments on baseless claims of election fraud or repeated attacks on Hunter Biden, the president’s only surviving son, who was recently convicted of a serious weapons offense. He often responded on topics that were favorable to him, such as inflation and immigration, including a question about the Jan. 6 riots on Capitol Hill.

“Let me tell you about January 6. On January 6, we had a great border. Nobody got through. Very few on January 6. We were energy independent on January 6, we had the lowest taxes ever. We had the fewest regulations ever,” he said.

Trump’s campaign team quickly declared victory.

“Tonight, before the largest voting audience in history, President Trump delivered the greatest debate performance and victory of all time, making clear how he will improve the lives of all Americans,” Chris LaCivita and Susie Wiles, senior Trump campaign aides, said in a statement.

“Joe Biden, on the other hand, has shown exactly why he should be fired,” they said. “Despite taking a week-long vacation to Camp David to prepare for the debate, Biden was unable to defend his disastrous record on economic and border issues.”

New rules ensure cleaner debates, but less resistance

Thursday’s debate featured new rules that, by and large, succeeded in ensuring a cleaner debate than in the past.

There was no audience in the studio to interrupt the candidates with applause or booing, and the microphones were turned off when the candidates were not given the floor.

The result was a debate with little clutter or disruption — a stark contrast from the primary debates earlier this year and the debates in 2020, when clutter made the candidates’ comments essentially unreadable.

Although the more rigid format helped to move the discussion along, there was little pushback from moderators Jake Tapper and Dana Bash, who sometimes preferred to move on rather than correct untruths or push for a direct answer to their original question when time had already been used up for a candidate to respond.

And yet the conversation became absurd at times: towards the end, the two candidates argued for minutes about their golf skills.

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

Lots of political talk, but little new

This structure also helped the moderators and candidates stick to their policies, but little was achieved in terms of the candidates’ positions on the main issues.

Biden promised to reinstate Roe v. Wade, protect abortion rights, raise taxes on wealthy Americans and support Ukraine.

Trump defended his tax cuts, said he would force European allies to step up their efforts to support Ukraine in its fight against Russia, and said Israel must be allowed to continue its military operations in the Gaza Strip.

However, voters will hardly receive any new information about the two candidates’ views on key issues that they have not already heard during the campaign.