What to Watch at the First Trump-Biden Debate

The candidates are the same. The circumstances are very different.

The first presidential debate of 2024 between President Biden and former President Donald J. Trump on Thursday offers both men the rare chance to tilt the direction of a race that has so far been defined by its stability.

Mr. Biden sought this historically early confrontation to force into focus the stark difference of their competing visions for America. His team wants to nudge voters away from seeing 2024 as an up-or-down vote just on Mr. Biden’s leadership — the buzzwords in Bidenland are choice and contrast — and warn that a second Trump term would be more radical and vengeful than the first.

Mr. Trump has been eager to debate, too. He sees Mr. Biden as cognitively diminished since they last clashed on the debate stage in October 2020. Mr. Trump is savoring the chance to lay into Mr. Biden’s record on the border and inflation in particular.

There is little mutual respect between them. The animosity is expected to be palpable inside the audience-free CNN television studio in Atlanta, where they will debate for 90 of the most consequential minutes of the campaign.

Here is what to watch for:

Can Trump make it about Biden? And vice versa?

The debate is a first in modern history because both candidates have already been president.

Voters know them. But many voters don’t like them. And so the imperative is to talk as much about the other guy and his record as their own.

The Trump team believes an election that is a referendum on Mr. Biden’s tenure — including long periods of high inflation, increased migrant border crossings and instability abroad in Israel and Ukraine — will result in a victory.

For Mr. Biden, making the debate about Mr. Trump means confronting him on his role in the Jan. 6 attack on the Capitol, his willingness to pardon people convicted in the riot — whom Mr. Trump has called “hostages” — and his promise to be a “dictator” on “Day 1.”

And one more — Mr. Trump’s new status as a convicted felon. The Biden campaign has begun to cast Mr. Trump’s legal woes under a broader umbrella that the former president is running mostly for himself.

For his part, Mr. Trump wants to avoid being dragged into a long back-and-forth on those topics. He has prepared for the debate with a series of discussions with allies and advisers that his team likes to brand “policy sessions.” Mr. Biden has been readying himself at Camp David, surrounded by his closest advisers for days of intensive preparations, with mock debate rehearsals that started on Monday.

Abortion vs. immigration: The debate within the debate

Mr. Biden and Mr. Trump represent fundamentally different approaches to the economy, taxation, abortion, the border, America’s role in the world and the democratic process itself.

The debate within the debate will be about which of these issues dominate the discussion.

Mr. Biden wants to pin down Mr. Trump on abortion. Four years ago, Mr. Biden said in a debate that Roe v. Wade was “on the ballot,” which Mr. Trump repeatedly denied. “It’s not on the ballot,” Mr. Trump said at the time. Since then, Mr. Trump has taken credit for the Supreme Court ruling that overturned the federal right to abortion.

Now, Mr. Trump says he wants to let states pass whatever abortion restrictions they want. He supports exceptions for rape, incest and the life of the mother.

Mr. Biden is expected to argue that Mr. Trump will eventually back a national abortion ban, and has opened the door to restrictions on I.V.F. or even birth control.

If abortion is Mr. Biden’s top topic, Mr. Trump’s team sees the border — and crimes committed by migrants who cross it illegally — as a weak spot for the current president.

In the most recent poll by The New York Times and Siena College, 84 percent of the voters who said immigration was their top issue believed Mr. Trump was better on the topic. The reverse was true of abortion, with 81 percent of those who rated that as their top issue favoring Mr. Biden.

Does Trump come out brawling?

Mr. Trump knows that his aggression in the first 2020 debate was so intense — “Will you shut up, man?” Mr. Biden sighed at one point — that it caused a backlash. But the former New York businessman has always been a relentless brawler on debate stages, comfortable with the kind of personal invective and insults rarely seen at this level of politics before his arrival.

For months, Mr. Trump has made casting doubts on Mr. Biden’s mental state a centerpiece of his 2024 campaign. He has scrambled to try to lift up those expectations in recent days. In May, Mr. Trump called Mr. Biden the “WORST debater” he had ever faced. By June, he was praising him as a “worthy debater.”

Pre-debate spin is the norm. But Mr. Trump and his team have gone far beyond that, indulging in baseless allegations that Mr. Biden will be on performance-enhancing drugs, a Trump hobbyhorse ahead of general-election debates since 2016.

“Trump is unhinged,” said Cedric Richmond, a former White House adviser who has been part of the Camp David debate-prep team. “Him and the truth aren’t on the same planet. It makes it difficult.”

How does Biden navigate the age question?

Mr. Biden, 81, is the oldest president in American history. Mr. Trump, 78, would break that record if he’s elected, turning 82 before his term would end. Yet months of polling show that voters are chiefly concerned with the incumbent’s capacity to serve.

Whatever one-liner Mr. Biden unfurls to defuse questions around his age and competence will be among the most scrutinized of the debate. There are risks of being too glib on a topic that some 70 percent of voters have concerns about. But he also needs to be forceful enough that his answer is not quickly forgotten. Those around Mr. Biden believe the public’s perception of his fitness will be shaped by simply demonstrating command of the issues for 90 minutes.

Few Americans — besides those who watched his State of the Union address in March — have seen more than short snippets of Mr. Biden of late. And while a strong performance won’t fully answer questions about his fitness to serve another term that would end at age 86, it would serve to quiet them. On the flip side, a stumbling showing would fuel doubts about Mr. Biden in the run-up to the Democratic convention.

Whatever happens, the historically early debate means it will be months until there’s a chance at a redo.

Who handles the new format better?

This debate will be different. For one thing, there is no live audience for the candidates to react to. For another, CNN has said that mics will be muted when candidates aren’t supposed to speak. The rules say the network’s moderators, Jake Tapper and Dana Bash, will use “all tools at their disposal” to ensure a civilized discussion.

The interplay between Mr. Biden, Mr. Trump and the moderators will be closely watched. Mr. Biden does not want to get bogged down in correcting every falsehood that Mr. Trump says. As Mr. Biden said in one 2020 debate, “I’m not here to call out his lies.”

Mr. Trump himself has framed the debate as a 3-on-1 contest while his advisers have lobbied for a hands-off approach from the moderators. “Will CNN decide that they are a facilitator?” Chris LaCivita, a top Trump adviser, told reporters on Tuesday. “Or will CNN become a participator?”

Mr. Trump and Mr. Biden will be standing at lecterns that are only eight feet apart, according to CNN. That means that even if a microphone is muted, they will be able to hear each other, adding another X factor.

Who can generate more memorable (meme-able) moments?

The debate will last only 90 or so minutes. But both sides are preparing for the minutes and hours that follow, which can just as heavily shape public opinion.

Mr. Trump has a MAGA army ready to amplify his greatest hits. Mr. Biden’s campaign has aggressively reached out to social-media influencers, too, but with some mixed results.

How important are these online influencers?

The Democratic Party just invited content creators to the party’s convention to help spread the word while former President Barack Obama met with 80 content creators in Los Angeles ahead of his joint fund-raiser with Mr. Biden this month to urge them to get engaged. “What’s the point in having four million followers if you’re not doing anything with it,” Mr. Obama told them.

Moments that go viral are typically unscripted — an eye-roll or even a fly landing on the vice president’s head. But modern campaigns think hard about generating memorable collisions on favorable policy terrain.

Adam Green, a co-founder of the Progressive Change Campaign Committee who has passed along recommendations to the Biden team, said that goal was to “capture policy debates through the prism of high-vibes moments likely to go viral afterward.” No matter how many winning exchanges a candidate has, Mr. Green warned, “if the ones that go viral don’t include those moments, you’re in trouble.”

Michael Gold and Ruth Igielnik contributed reporting.