Explained: The rules for first US presidential debate

US President Joe Biden and his Republican challenger Donald Trump will face off in their first debate on Thursday, with the rules of the event diverging from previous debates.

The event will be hosted by CNN in Atlanta, Georgia, and moderated by network anchors Dana Bash and Jake Tapper, who will “use all tools at their disposal to enforce timing and ensure a civilised discussion”.

The moderators will be looking to avoid a repeat of one of the 2020 debates, which also featured Mr Biden and Trump, and often devolved into chaos.

This is the first of two scheduled debates, with the second to take place on September 10.

The format

The debate is expected to occur over the course of 90 minutes, with two breaks for advertising.

In a shift from previous years, candidates will not be giving opening statements.

Instead, they will each have two minutes to respond to a question, with one-minute rebuttals and responses to rebuttals.

The moderators will have an extra minute to use at their discretion.

At the end of the debate, each candidate will have the opportunity to present a two-minute closing statement.

Following a coin toss, Mr Biden has chosen to stand at the podium on viewers' right and Trump has opted to deliver his closing statement last.

No audience and muted mics

Both campaign teams have agreed the debate will take place without a live audience and with microphones muted unless a candidate is directed to speak.

This is the first time a presidential debate will take place without a studio audience since 1976.

The muted microphones are also a first and will, it is hoped, not allow for interruptions.

During one 2020 debate, Trump frequently talked over and interrupted Mr Biden, who famously told his opponent: “Will you shut up, man?”

No notes, no help from staff

In another departure from the usual debate rules, the two candidates will not be allowed to bring any written notes with them.

They will be provided with pen and paper as well as a bottle of water.

During the two commercial breaks, the candidates will not be allowed to speak or interact with campaign staff.

These rules are a reflection of growing concern over the age and mental acuity of the candidates.

At 81, Mr Biden is the oldest US president in history and is well known for his verbal gaffes. Trump is 78 and renowned for his nonsensical rambles.