Analysis: Five months from election day, Joe Biden and Donald Trump are meeting head-to-head for the first presidential debate.
It's the first time the two have met since Biden took over in the White House, and the stakes are unusually high.
Polling shows the margin between the two candidates is razor-thin, and both will be hoping to gain an edge, if not land the knockout blow.
But what makes this election particularly interesting is how unpopular both candidates are.
Biden's approval rating is in the doldrums, with voters uneasy with the 81-year-old being in charge for another four years.
Trump, 78, meanwhile carries the weight of a potential prison term, and swing voters are asking if they want another term like his first.
This is not an ordinary election, and this is not an ordinary debate. Here's what to look for:
What makes this debate so different?
Usually the format of debates are set by a nonprofit corporation called the Commission on Presidential Debates.
But both Biden and Trump's campaigns were unhappy with the commission, and opted to go around them.
Instead the debate will be broadcast on CNN, moderated by network anchors Jake Tapper and Dana Bash.
The debate can also be watched live on 9Now at 11am AEST. You can also follow our live blog on 9News.com.au.
Unlike previous debates, this one will be held in a studio without an audience.
And to avoid the constant interjections that marred the first 2020 debate, candidates' microphones will be switched off when it isn't their turn to speak.
Who will have a harder time defending their record?
Usually incumbent presidents struggle in debates because they have to defend things that happened during the past term.
But both Biden and Trump have records they have to explain.
Trump will likely jab Biden over the economy and crime - even though unemployment and crime have both sharply declined during his presidency.
Biden will likely take a swing at Trump over abortion, the wedge issue Republicans have been flailing over since the Supreme Court overturned Roe v Wade.
Biden may also mention how Trump has been found guilty of 34 criminal counts, and is facing three other criminal trials.
Will Trump announce his vice president?
Donald Trump has been teasing a revelation of his running mate for weeks now, and there's some chance he could drop the name at the debate.
The announcement would certainly cause a stir.
Biden may be preparing for this, ready to define the would-be 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's done it several times in the past few weeks, even calling on the sitting president to take a drug test.
But much of this depends on which Biden shows up. At times Biden appears frail and soft-spoken. Other times, like at the State of Union, he is in full-voice and bullish.
Both Trump and Biden are teetotallers and have strong personal views against drug use.
Can one candidate take a debate win to an election victory?
Pundits speculated this presidential debate is being held much earlier than the election is because both candidates wanted to blunt the impact of a bad performance.
But voters in the US have become especially calcified in the past decade, and there's few swing voters up for grabs. Most people watching will be cheering on their preferred candidate, and they usually think their favourite politician won.
But given both candidates have a long history of verbal slip-ups, 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 be crossing their fingers in the hope 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 in our live blog.
