US Election Second Debate: Everything you need to know about Harris v Trump

• Harris and Trump will debate each other live on 10 September

• Victory could give candidate advantage in close election

• Find out where, when, rules about mics and why debates matter

When is the second US presidential election debate?

The second US presidential debate takes place on 10 September 2024 at the National Constitution Center in Philadelphia.

ABC News is hosting the debate and it will start at 21:00 US Eastern Time which will mean a late night for UK viewers as that is 2am our time. Get used to it because US election night is often an all-nighter for politicos on this side of the Atlantic.

The debate should last for 90 minutes and it will be moderated by American news anchors David Muir and Linsey Davis

On 1 October, Tim Walz and JD Vance - the respective Democrat and Republican candidates for vice president - will debate each other.

What are the rules of the second US election debate?

There has been conisderable controversy about the debate rules and the details still remain a little sketchy.

The 10 September debate was thrown into jeopardy when Donald Trump indicated that he would only take part if the candidates' microphones were muted while their opponents were talking.

Harris' team did not want to mute the mics while the other candidate was talking and claimed: "Trump's handlers prefer the muted microphone because they don't think their candidate can act presidential for 90 minutes on his own."

It should be noted that muting the mics was intiailly the Democrats idea because they were tired of Trump interrupting. When they saw that muting Trump in the first debate just let Biden talk himself into more problems they changed their minds.

Trump has since said that he will take part on 10 September and the debate is set to go ahead with muted microphones.

At the first debate, when Biden faced Trump, the candidates weren't allowed to talk to their staff during breaks or bring any notes with them.

What happened at the last US election debate?

The first US presidential 2024 debate proved pivotal and lead to Joe Biden abandoning his bid to win a second term in the White House.

Biden struggled with his memory, appeared unable to think on his feet, and allowed Trump to win the debate without really doing anything to merit victory. At one point, Biden challenged Trump to a round of golf.

For Biden, the fall out from the debate was fatal. He tried to salvage his campaign, holding rallies where he claimed he was up to a second term as president, but after weeks of pressure bowed out and endorsed Harris.

It will be the first time Harris and Trump debate each other and it could be the last. Earlier this year, the Biden and Trump campaign agreed that their candidates would take part in two debates and this is the second of those.

Trump has proposed two further debates but the Harris campaign has yet to agree to those. That could change, however, so watch this space.

Do US election debates matter?

Yes. For candidates who are trailing int the polls, it is a chance to cut through to the electorate and get themselves back in the race, while for the favourite it as an opportunity to put clear distance between themselves and their opponent.

The first US presidential election debate took place in 1960 when Richard Nixon and John F. Kennedy clashed live on TV for the first time. TV was key as, famously, those who watched thought Kennedy, who was younger and taller than his opponent, was the clear winner, while for radio listeners Nixon came out on top. Kennedy went on to win the election.

Not that youth is always an advantage. When Ronald Reagan, who was 73 and then the oldest president, debated 56-year-old Walter Mondale in 1984, the older man got to the heart of the matter, telling Americans: "I want you to know that, I will not make age an issue of this campaign. I am not going to exploit, for political purposes, my opponent's youth and inexperience." Reagan won the election and a second term in the White House.

Barack Obama suffered a surprising defeat to Mitt Romney in their first debate in 2012. In the second debate, however, a clearly smarting Obama rallied and took the fight to his opponent. Romney was rattled by questions about gender equality and famously said he had "binders full of women" who he would consider appointing to jobs in his administration. This weird phrase haunted him for the rest of the campaign and Obama won the election comfortably.

Hillary Clinton was expected to beat Donald Trump in 2016 and, with her command of policy and experience in office, she should have trouced him in the debates. It did not work like that, however, even when they faced each other after the notorious "pussy-grabbing" tape of Trump went viral. Trump kept his cool in the debate, though, and come November pulled of political earthquake by winning the election against the odds.

Presidential debates can be key moments in election campaigns. With the odds on Harris and Trump tight in the Betfair Exchange election winner market, their date on 10 September could be one of the fiercest and most important ever.

Now read US Election Winner Betting: How to use Betfair odds to project the Electoral College