Donald Trump and Joe Biden are supposed to go head-to-head in three debates. But these dates have been thrown into doubt by the president's being taken to hospital with coronavirus.
The second debate between Mr Trump and Mr Biden, set for October 15, could in theory still go ahead if the president recovers.
Mr Biden, who duelled with Mr Trump in a bad-tempered and fiery first debate last month, has tested negative.
The coronavirus pandemic has drastically changed how the Republican and Democratic presidential campaigns will be fought this year, meaning the debates have taken on even more significance than in previous years.
The televised debates are likely to be the only times the two presidential candidates appear alongside each other before the US election day on November 3 and the encounters are expected to produce some of the top political moments of this campaign season.
There is also one debate scheduled for the two parties' vice-presidential candidates, Mike Pence and Kamala Harris.
When, where and what time are the debates?
September 29, Ohio
The first presidential debate between Mr Trump and Mr Biden was a chaotic squabble between the two candidates.
The rivals ripped chunks out of each other on their records and issues such as the economy, coronavirus and racism.
Mr Trump was rebuked several times by Chris Wallace, the moderator, for speaking over his opponent. At one point, after incessant interruptions from the president, Mr Biden said: "Will you shut up, man?"
Read more: Who won the US election debate?
October 7, Utah
The sole vice-presidential debate, between Democratic senator Kamala Harris and Mr Trump's vice president, Mike Pence, will be in Salt Lake City, Utah, on October 7 at 9pm ET (2am Thursday in the UK).
The 90-minute debate will be moderated by Susan Page from the newspaper USA Today, and divided into 10-minute segments.
October 15, Florida
If Mr Trump recovers from his coronavirus infection, the second debate between the two presidential candidates will be hosted by the Adrienne Arsht Centre for the Performing Arts in Miami on October 15 at 9pm ET (2am in the UK).
The 90-minute debate will be moderated by Steve Scully from the public service network C-SPAN and will take the form of a town hall event, with Miami residents in the audience posing their own questions to the two candidates.
The candidates will be given two minutes to answer each question and the moderator will be allowed an additional minute to enable follow ups. The members of the audience called on to ask questions will be uncommitted voters chosen by an analytics firm, Gallup.
October 22, Tennessee
The final presidential debate will be at Belmont University in Nashville, Tennessee, on October 22 at 9pm ET (2am UK).
The 90-minute event, moderated by NBC News correspondent Kristen Welker, will also be divided into 15-minute segments on prepared topics.
How can I watch the debate in the UK?
Each debate will be streamed by all major US networks, including ABC, CBS, NBC, Fox News, CNN and MSNBC.
The Telegraph will be livestreaming the first debate - watch it above or on YouTube here.
What do we know about the moderators?
The key details for the debates, as well as who moderates them, are decided by the non-partisan Commission on Presidential Debates.
Moderators can play an outsized role in how the candidates fare because they choose the questions, can push back on vague responses and dictate how many interruptions they allow.
Unlike in previous years, there is only one moderator in each debate as a way to limit the number of people on stage during the coronavirus pandemic.
The Trump campaign outlined its preferred moderators, including a number of Fox News hosts and conservative commentators, in a list that Rudy Giuliani sent to the commission, but none of the suggestions were selected.
The initial debate was overseen by Chris Wallace, a host from Mr Trump's favourite network Fox News, but one of his toughest questioners at the network.
Mr Wallace was criticised for losing control of the discussion and allowing Mr Trump to frequently speak over his opponent.
Mr Trump may be pleased that none of the three moderators will be from CNN, unlike in 2016.
The second debate will be moderated by a journalist from the public service network C-SPAN, and the third by one from NBC. The single vice-presidential debate will be moderated by a USA Today newspaper journalist. How important the moderators can be has been shown repeatedly over the years. Their actions can help decide an election.
What does Trump getting coronavirus mean for the debates?
The second debate has not yet been cancelled and is theoretically still on the cards.
In the US those who test positive for coronavirus must self-isolate for 10 days. This means Mr and Mrs Trump could be out of the White House by October 11.
But rules dictate those who show symptoms of the virus, including a high temperature, continuous cough or loss of taste or smell, must isolate for 10 days from the date symptoms first appear.
This could put the next showdown, hosted by public service C-SPAN anchor Steve Scully in Miami on October 15, at risk of being postponed.
The debate differs from the first in that it is modelled on a town hall, with Miami residents in the audience given the opportunity to quiz Mr Trump and Mr Biden.
Mr Scully has been dubbed “the most patient man in television” which, if the debate runs anything like the first round, is probably for the best.
Read more: Donald Trump faces uncomfortable questions at a turning point for the US election
What else do we know about the debates?
With Mr Trump unable to hold his usual large campaign rallies, the debates offer his best shot at narrowing Mr Biden’s poll lead, and the president intends to use the TV appearances to land as many blows as possible.
In the first debate, Mr Trump was able to land several blows on his rival.
The president had been preparing for the debates for some time, with Chris Christie, the former New Jersey governor reportedly playing the role of Mr Biden during his practice sessions.
With Mr Biden avoiding rigorous interviews the debates may prove to be the most arduous test he faces throughout the campaign.
