US Election: Five presidential debates that proved crucial

• Get ready for 10 September debate with our guide to five that mattered

• Check out our 2024 US Presidential Election Live Blog here

• Get latest data including current prices and volume of bets in our daily update

Donald Trump is the marginal favourite on the Betfair Exchange to win the US election against Kamala Harris. But favouritism has swung back and forth in recent weeks and both candidates would love to land a knockout blow in Tuesday's live televised debate.

The 2024 election has been a huge betting event so far and it will only get bigger as race hurtles towards election day on 5 November.

To get you in the mood for the debate on 10 September - which starts at 9pm EST and 2am UK time - here's a rundown of five that help to decide the outcome of an election.

1960 - Nixon sweats as JFK shines

Arguably the most iconic US presidential election debate moment came in the first ever on TV in 1960. Richard Nixon spent eight years as Dwight Eisenhower's vice president and now it was the pugnacious Republican's shot at the big job. However, John F. Kennedy was a different kind of candidate than America had seen before and he was perfect for TV.

Kennedy shone under the studio lights, exuding youth and confidence, while Nixon visibly sweated. Kennedy went on to win the election, although Nixon did, of course, win the White House in 1968 before his presidency spectacularly imploded during the Watergate scandal.

1984 - Reagan shows age is no obstacle to winning

Ronald Reagan outperformed Jimmy Carter in 1980 and won the presidency. Four years later, he was up against Walter Mondale in 1984. By now Reagan was 73 - by then the oldest president - while his opponent was a mere 56-year-old. Was Reagan too old for a second term? "I want you to know that, I will not make age an issue of this campaign," he told voters. "I am not going to exploit, for political purposes, my opponent's youth and inexperience." Reagan won the debate, election and has gone down in modern history as the Republican president against whom all others are measured .

1992 - Are we keeping you, Mr Bush?

Not looking bored in a presidential debate is a good idea. It seems obvious but apparently George H.W. Bush, the then president, did not know this when he looked at his watch during a televised debate against Bill Clinton and Ross Perot in 1992. The gaffe added to the impression of Bush as an imperious figure who, due to his wealth and 12 years in government (he served eight as Reagan's vice president), was above trifling matter such as election debates. He went on to lose to Clinton.

2016 - Trump survives somehow

The second debate, on Sunday 9 October 2016, should have been the moment when Hillary Clinton buried Donald Trump's bid for the presidency. Two days earlier, the notorious tapes of Trump talking about "pussy-grabbing" had been leaked and gone viral and his campaign looked finished. His strategy was expected to be damage limitation but instead he shamelessly went on the offensive, talking about Bill Clinton's alleged misdemeanours, Hillary Clinton's emails and vowed to have her prosecuted if he won the election. It was perhaps the ugliest presidential debate ever witnessed and, in hindsight, looks like a turning point for his victorious campaign.

2024 - Biden blows it and paves the way for Harris

Whatever you think of his presidency, it was sad watching Joe Biden struggling to remember facts, rambling on and challenging Trump to a round of golf at their debate in June. Even Trump looked shocked by the chaos of Biden's performance. But it was difficult to feel sympathy for Biden, and acknowledge that he was simply suffering from the kind of decline that comes to many of us eventually, when he insisted he would continue his campaign for a second term as president.

Fortunately, Biden was persuaded to stand aside and, on 21 July, he announced that he was endorsing Harris to replace him as the Democratic nominee. From that moment, she has not looked back, her momentum has ignited the betting and, when she takes on Trump in Tuesday's debate, the stakes could not be higher.

Now read US Election: First Debate has potential to turn the odds upside-down