Five things to look for at the first US presidential debate between Joe Biden and Donald Trump including rules and changes

This is the first time the two have met since Biden took over the White House, and the stakes are unusually high.

The survey shows that the gap between the two candidates is razor thin and both will be hoping to gain an edge, if not a knockout.

But what makes this election particularly interesting is how unpopular both candidates are.

Biden’s approval rating has stalled, with voters uneasy about the 81-year-old’s four more years in office.

Meanwhile, Trump, 78, is carrying the weight of a potential prison sentence and voters are questioning whether they want another term like his first.

This is no ordinary election and this is no ordinary debate. Here’s what to look for:

What makes this debate so different?

Typically, the format of the debates is set by a nonprofit corporation called the Commission on Presidential Debates.

But both the Biden and Trump campaigns were unhappy with the commission and chose to bypass it.

Instead, the debate will air on CNN, moderated by network anchors Jake Tapper and Dana Bash.

The debate can also be seen live on 9Now at 11am AEST. You can also follow our live blog at 9News.com.au.

Unlike previous debates, this one will take place in a studio without an audience.

And to avoid the constant interjections that marred the first debate of 2020, the candidates’ microphones will be muted when it’s not their turn to speak.

Who will have a harder time defending their record?

Incumbents usually struggle in debates because they have to defend things that happened during the past term.

But both Biden and Trump have records to explain.

Trump is likely to hit Biden on the economy and crime — even though both unemployment and crime have fallen sharply during his presidency.

Biden is likely to take a swing at Trump on abortion, the issue Republicans have been rocking since the Supreme Court overturned Roe v. Wade.

Biden may also mention how Trump has been found guilty of 34 criminal charges and faces three other criminal trials.

Will Trump announce his vice president?

Donald Trump has been teasing his running mate’s revelation for weeks now, and there’s some chance he’ll drop the name during the debate.

The announcement is sure to cause a stir.

Biden may be gearing up for it, ready to define the future vice president in the public’s mind before they can do it themselves.

Will Trump accuse Biden of drug use?

For the third election in a row, Donald Trump has accused his opponent of using performance-enhancing drugs in debates.

He has done so several times in the past few weeks, even urging the sitting president to take a drug test.

But a lot of that depends on which Biden turns up. At times, Biden appears fragile and soft. Other times, like in State of the Union, he’s in full voice and whipping.

Both Trump and Biden are sober and have strong personal views against drug use.

Can a candidate parlay a debate victory into an election victory?

Pundits speculated that this presidential debate was being held much earlier than the election because both candidates wanted to blunt the impact of poor performances.

But the US electorate has become particularly calcified in the past decade, and there are few swing voters up for grabs. Most people watching will support their preferred candidate and usually think their favorite politician won.

But given that both candidates have a long history of verbal gaffes, this debate could be particularly influential in how people vote.

Both Trump and Biden need to show that they are up to the job. They’ll cross their fingers hoping the other one screws up.

You can watch the debate live on Nine and 9Now at 11am AEST. You can also get the latest updates, analysis and reactions on our live blog.