On Thursday, the early hours of Friday Irish time, US president Joe Biden and Republican candidate Donald Trump will go head-to-head in the first debate ahead of the November election.
While these occasions have devolved into glorified shouting matches, they hold a key place in the history of US campaigns.
Here, we have a look at some of the debates that had a huge impact on who ended up in the White House.
John F Kennedy v Richard Nixon, 1960
The first ever televised presidential debate had a huge role in John F Kennedy winning the presidency.
Heading in to the debate, then-vice president Nixon had a slim advantage over JFK, then a senator from Massachusetts.
It was the first time appearance and energy was just as important as the substance of the debate.
The younger JFK wore makeup, and was impeccably tailored. In contrast, Nixon declined to wear makeup and wore a suit that looked slightly too big for him.
Even on the black-and-white television sets, Nixon was also visibly sweating.
While the debate was well-matched, JFK's youthful appearance swung it in his favour, with most Americans who watched on TV saying the Democrat won the debate, while more radio listeners said it went Nixon's way.
Jimmy Carter v Gerald Ford, 1976
The JFK-Nixon debate was not followed for a long time, until president Gerald Ford decided he needed to face Jimmy Carter, who was ahead in the polls, in front of the nation.
Carter was then the governor of Georgia, and the televised debates gave him a chance to secure his lead.
The debates are most well-known for an odd pronouncement Ford made in the second debate: “There is no Soviet domination of Eastern Europe, and there never will be under a Ford administration.”
It's unclear whether the gaffe swung public opinion in Carter's favour, but it certainly didn't help Ford.
Jimmy Carter v Ronald Reagan, 1980
Carter had avoided the charismatic Reagan for most of the 1980 campaign. However, realising he needed a boost in the final stages, he agreed to a debate.
Carter accused the Republican of planning to cut healthcare funding for elderly people. Claiming his words were twisted, Reagan replied "there you go again," prompting cheers from the audience.
Reagan went on to win the election, denying Carter a second term.
George HW Bush v Bill Clinton v Ross Perot, 1992
This unusual three-person debate went against the incumbent, George HW Bush.
In a bad PR moment for the president, he was caught looking at his watch, with many viewers feeling it projected a sense of complacency and a lack of respect for his opponents.
He later admitted what he was thinking. “Only 10 more minutes of this crap.”
In the end, Bill Clinton won the election, and third-party candidate Perot had a big say in the result as he took 18.9 per cent of the national vote.
Third-party candidate Robert F Kennedy Jr is hoping to have a similar impact on the 2024 election, but the Biden and Trump camps will be relieved that his efforts to be included in the CNN debate have not come to fruition.
George Bush v Al Gore, 2000
This was a very tightly contested election, but Al Gore came into the debates leading Bush in most of the polls.
While many felt Gore won the debates, his aggressive style put many viewers off.
He was caught loudly sighing at one of Bush's answers, while he walked towards Bush while he was talking in the third debate. Bush smiled and continued to speak.
In the end, the 2000 election was ultimately decided by the Supreme Court, in Bush's favour.
Donald Trump v Hillary Clinton, 2016
The first debate between Trump and Clinton drew a record 84 million viewers.
The following two both had more than 60 million viewers, and while political analysts said Clinton won all the debates easily, they were an example of how soundbites became more important.
The standout moment came when Clinton said the United States would be in a perilous situation with someone with Trump's temperament in charge, to which he replied: "You'd be in jail."
Trump was also criticised for standing behind Clinton in what looked like a threatening manner at various points.
Donald Trump v Joe Biden, 2020
Like the current situation, Trump and Biden were neck and neck heading into the 2020 election.
This was an example of how the civilised debate first shown by JFK and Nixon had really devolved, as Trump continually tried to shout over his opponent.
However, it backfired on Trump as the key moment was Biden's response: "Will you shut up, man?"
The second debate was cancelled as Trump tested positive for coronavirus.
Donald Trump v Joe Biden, 2024?
With Trump holding a lead in the majority of polls, there is a huge amount riding on this debate.
Like some of the previous incumbents, Biden has likely only agreed as he feels he has ground to make up, and there are big risks for him, as there are for Trump.
Trump, 78, and Biden, 81, are the oldest presidential candidates ever and both will be looking to project an energetic and commanding presence.
Issues like the economy and immigration will likely come up, but expect plenty of personal attacks.
Trump is likely to zone in on the recent federal gun charges Biden's son, Hunter, was found guilty of. Meanwhile, viewers will be wondering when Biden chooses to bring up Trump's own conviction, in the high profile New York hush money case.
To prevent the candidates shouting over each other, mics will be switched off while their opponent is speaking.
The 90-minute debate starts at 2am Irish time.
