Stage set for Trump and Biden's first 2024 debate showdown

The two oldest candidates ever to run for US President are all geared up to meet on June 27 for a televised debate unlike any other. One accuses his rival of being unhinged and a danger to democracy, while the other accuses his opponent of being senile and corrupt.

President Joe Biden, 81, and former President Donald Trump, 78, are essentially tied in national opinion polls with fewer than five months until the November 5 election.

Many voters remain undecided, raising the stakes of a debate that will be viewed more for possible moments of drama than for policy discussions between the Democratic president and his Republican challenger.

Here are the top things to watch for in the debate broadcast from Atlanta.

Fitness question

Both candidates may face questions about their fitness to serve in ways previous presidential hopefuls have not.

Trump claims Biden is physically and mentally unfit for office, while Biden has called his predecessor "unhinged" and a danger to democratic norms.

Democrats point to Trump's role in the January 6, 2021, attack on the US Capitol by his supporters, his other efforts to overturn the 2020 election, and his conviction on May 30 on 34 felony counts for his involvement in a "hush money" scheme to keep an alleged sexual encounter from the public.

Biden’s mental and physical strength has been the subject of scrutiny and speculation as he seeks a second four-year term.

Critics say he is slowing down and point to a series of verbal slip-ups; allies claim he is as sharp as ever. Trump regularly mocks Biden at rallies, suggesting he’s not up to the job.

The president’s age is also on most voters' minds, including Democrats, and many viewers will be on alert for any sign that Biden - or Trump - is not up to the task.

Trump has not faced the same questions about his stamina but has raised eyebrows with his tendency to go off on extended tangents and occasionally mixing up names.

Temperament test

Both candidates are known for their tempers and impatience. They are used to commanding the stage and getting their way. Both have been president and likely see little reason to yield to the other.

"There is a lot of bad blood," said Tevi Troy, a former George W. Bush official who helped that Republican president prepare for the 2004 debates against Democrat John Kerry.

Biden rattled Trump during their first debate in the 2020 race, leading Trump into what was viewed as a poor performance as the Republican repeatedly interrupted and bickered with the moderator.

Trump may try to get under Biden’s skin by mentioning the legal problems of the president's son, Hunter, who was convicted of lying about his drug use to illegally buy a gun.

Joe Biden is well practiced at deflecting such comments, but viewers will be looking for any sign that the president cannot maintain his poise under fire.

Trump has to be careful, too, not to turn off moderate voters. "You can’t be so aggressive that you are rude, and you seem to be trampling your opponent," said Brett O’Donnell, a veteran Republican debate consultant.

Narrative trap

There will be a strong temptation for Biden to lean into Trump's conviction in New York. O’Donnell said that would be a bad idea because it would further Trump’s unsupported contention that Biden was involved in bringing the charges and that Trump is a victim of political persecution.

The Biden campaign recently launched a $50 million ad campaign highlighting Trump's guilty verdict, suggesting the president's team views it as a winning issue.

For Trump, the danger lies in saying things that underscore Biden’s argument that he is a threat to democratic norms. Trump, for example, has suggested he will use the Justice Department to target his political enemies.

"Trump has to seem presidential, said Aaron Kall, a University of Michigan expert on presidential debates.

Trump may also be tempted to complain, as he frequentl y does on social media, about forces working against him or cast himself as a victim of a political conspiracy.

Political experts said the candidates should emphasise cost-of-living issues - such as high grocery, housing and energy prices - to show they are in touch with voters' sentiments.

Biden has been trying to reassure voters about the economy for months with mixed results, and Reuters/Ipsos polls have shown Trump with an edge over Biden as the candidate voters trust to handle the economy.

No audience feedback

In a sharp departure from previous presidential debates, there will be no studio audience. That could pose problems for both candidates, but perhaps particularly for Trump, who draws energy from a boisterous crowd.

The candidates might be somewhat at sea, getting no real-time feedback as to how their arguments and attacks are being received, Kall said.

With no voters in the room to pander to, the candidates also may be more substantive and less histrionic. CNN has said a candidate's microphone will be turned off to prevent interruptions when the other is speaking.

A key to debate success may be which candidate makes the format work best by connecting viscerally with viewers at home.

Trump will get the final word in the debate, CNN said on Thursday. The Biden campaign won a coin toss to determine podium placement and the order of closing statements, and chose to have Biden on the right side of viewers’ screens during the debate.

The Trump campaign then opted to have Trump deliver the last closing statement.