The questions have begun with a question about inflation - and what Joe Biden says to voters who feels they are "worst off".

Biden quickly shifted the response to say that Trump "left him" a collapsed economy, with rising unemployment.

"We had to put things back together again," he said, adding that things were "terrible" under Trump and that he "didn't do much at all".

He used the word "chaos" several times.

The president and former president took the stage without shaking hands. Biden entered first and Trump did not look in his predecessor's direction when he stood behind the lectern. No niceties tonight.

Image source, Reuters

Joe Biden and Donald Trump have taken the stage.

Image source, CNN/Reuters

CNN has a few rules to try to keep tonight’s debate running smoothly. Here’s what we know:

• The debate is 90 minutes long, with two commercial breaks
• Trump and Biden can’t talk to their staffers during those breaks
• Microphones will be muted for the whole debate, other than when it’s a candidate’s turn to speak
• Props and pre-written notes are not allowed
• But Biden and Trump will be provided a pen and paper, and some water
• There will be no studio audience
• A coin flip decided which side of TV screens they will be on (Biden on the right, Trump on the left) and also who will speak last (Trump)

The CNN Presidential Debate has begun.

You can watch the CNN Presidential Debate on CNN or simulcast on the BBC News channel, BBC website and app, including at the top of this page.

Image source, Getty Images

This first presidential debate will be moderated by CNN’s Jake Tapper and Dana Bash.

The pair, who co-anchor the political programme State of the Union, also moderated one of the Republican presidential debates in Iowa earlier this year.

You might recall those debates missed a key player in this race to the White House - Donald Trump.

He refused to take part in any of the debates aheadof Republican primary voting. But sitting out didn’t hurt his chances, as Trump is now the last politician standing for the party.

Tapper and Bash will likely have some strong ideas on how to moderate tonight based on what they said after Trump and Biden’s first presidential debate in 2020. Here’s a taste of what they thought back then:

Tapper: “A hot mess inside a dumpster fire, inside a train wreck. That was the worst debate I have ever seen."

Bash: “That was a shitshow... that is only phrase I can think of that describes it.”

And Trump is no fan of CNN. It was among the first outlets he branded as “fake news”, one of the most common verbal attacks he uses against media.

Joe Biden and Donald Trump are gearing up to meet face-to-face for the first time in nearly four years in their 2024 rematch for the Oval Office.

You can watch the CNN Presidential Debate on CNN or simulcast on the BBC News channel, BBC website and app, including at the top of this page. The debate starts at 21:00EDT (02:00BST).

Stick with us as we bring you all the news and analysis before, during and after the match-up.

In the spin room is a familiar face from Trump’s political history: Corey Lewandowski, who was Trump’s first campaign manager in 2016. Trump fired him around this time in the 2016 campaign as he tried to shift strategy.

But Lewandowski has continued to work within Trump world, and he said he flew to Atlanta on Trump’s plane, telling reporters the former president was in a “great mood.”

Tonight, Lewandowski also floated attacks on Biden’s physical stamina that Trump’s campaign has advanced in the days leading up to the debate.

He claimed there was “some speculation” about 81-year-old Biden being able to stand for the duration of the debate. (Trump himself is 78.)

Image source, Getty Images

I asked Lewandowski if it was wise for the Trump campaign to simultaneously try to acknowledge that Biden was a good debater in the past, as Trump himself did last week, while campaign aides also suggested without evidence that Biden might use substances like Adderall to get through the debate.

Lewandowski tried to thread the needle as well.

“I think Joe Biden has been a professional politician for north of 50 years now,” he said. “He’s debated dozens and dozens of times.”

“I think the expectation is he is going to have a good night for him,” Lewandowski said. “It’s up to the American people to decide if that is a night where he can stand at a podium for 90 minutes, put coherent sentences together, and lay out a vision for America.”

“But he also still has to defend his policies over the last three years,” Lewandowski said, including Americans' frustrations with the economy and immigration policy.

Image source, Reuters

The former president has arrived with a group of his long-time aides, including Jason Miller, Dan Scavino and David Bossie.

But notably missing from his entourage was his wife, Melania Trump, who has been mostly out of the public eye during his 2024 campaign.

It’s been almost four years since Donald Trump and Joe Biden appeared in the same room together.

The last time was also a presidential debate - their second encounter in the 2020 race.

Soon after that, Trump lost the election and refused to accept defeat. In November 2022 he started his campaign for another shot at the White House – earlier than any major candidate in modern US history.

He’s made more history since then - becoming the first former president convicted of a crime.

Meanwhile Biden has had a tumultuous term in office - dealing with wars in Ukraine and Gaza, voter anger over high inflation, and a spike in undocumented migrants at the US-Mexico border.

All of this will be grist for the mill in tonight’s debate, which is set to start in minutes.

Tens of millions of Americans will be watching, some paying close attention to the candidates for the first time this year.

While election day is still months away, this is the biggest moment of the campaign so far.

We've just heard from the travel pool reporters that are with President Biden - at 20:27 local time, his motorcade began headed to the site of the CNN Presidential Debate.

A Washington Post reporter on the scene said that the president waved through the window of the "Beast" - his armoured vehicle - as it drove past the vans carrying the pool reporters.

Five minutes later, the motorcade arrived.

News flash: The two men running for president are old. Joe Biden is 81, and Donald Trump is 78.

Partisans on both sides are hoping to convince voters the other guy is too ancient and out of it to be an effective president.

So far, Trump’s supporters have had more success at this game. A video of Biden appearing to wander off at the G7 summit recently went viral and even ended up on major news sites.

However, it was deceptively edited to cut a group of parachutists that Biden was gesturing to out of the frame. Viewed from another angle, Biden perhaps looks a little stiff, but his actions make sense.

Biden’s supporters have hit back, with videos of Trump making long pauses at rallies or forgetting the names of close associates.

If there’s similar so-called wandering, pausing or name-forgetting tonight, you can expect short clips of such moments to spread like wildfire.

The footage may be real – and it may underline legitimate concerns about the age of the candidates. But just as likely, it may be manipulated, taken out of context or deceptively edited for political purposes.

Luckily, there’s an easy solution: watch the original footage and make up your own mind.

On his own Truth Social media platform, former president Donald Trump appeared to share some debate "talking points" he received from Andrew Wheeler, the former head of the Environmental Protection Agency.

The talking points from Wheeler - who served as EPA head in the Trump administration between 2019 and 2021 - included a claim that CO2 emissions went down, and that "everyone is buying Chinese solar panels" because of Biden's "climate and tariff policies".

On X, the platform formerly known as Twitter, Biden campaign rapid response director Ammar Moussa posted the notes with the response "thanks I guess".

Our North America correspondent Anthony Zurcher is on the ground in Atlanta.

Here's a look inside the spin room where allies of the president and former president will gather to praise their candidate and pan their opponent following the debate.

Image source, Getty Images

The first time these two men faced off in a presidential debate in 2020, it wasn’t pretty.

Back then, our North America Correspondent Anthony Zurcher described the constant interruptions and insults as the political equivalent of a food fight.

Open to Debate, a non-partisan non-profit organisation, counted 76 times, external where the two men talked over each other in that debate. For comparison’s sake, there was one instance of someone talking over the other candidate in a 2004 debate between George W. Bush and John Kerry.

After that first “food fight” debate in 2020, moderators at the second debate muted the microphones at the candidates’ podiums when it was not that candidate’s turn to speak. That measure reduced “cross talk” down to four instances, according to Open to Debate.

That’s why we’re getting muted microphones tonight.

Vivek Ramaswamy, the pro-Trump entrepreneur who ran for the Republican nomination before dropping out in January, is on the spin room floor ahead of the debate, holding court in front of a pack of reporters.

In his view, the tone of the debate will hinge on the CNN anchors Jake Tapper and Dana Bash and if they let the candidates focus on "positive" questions and policy discussion, or focus on events like the January 6th riot at the US Capitol that was led by Donald Trump's supporters.

“The moderators have a pre-baked agenda," he claims, repeating a Trump talking point. "Which CNN shows up - I think that's the real question for tonight, not which Biden or Trump shows up."

Ramaswamy was also asked, naturally, about who Trump should pick as VP.

He said that person should be someone who can "expand Trump's base of voters" but also "stay true" to the America First movement and its principles.

Image source, Brandon Drennon

In Republican areas of Georgia, appreciation for Donald Trump carries an almost Taylor Swift-fan energy.

When he holds rallies, thousands show up from across the state and arrive to enter at the crack of dawn.

Georgia – mostly rural outside of Atlanta – also has an entire store dedicated to Trump merchandise.

At the Trump Store & More, Trump’s face is printed onto everything from pins to pocketknives.

There are the classic screaming-red “MAGA” caps, and bottles of FJB hot sauce. (The F stands for an expletive. The JB stands for Joe Biden.)

Biden’s name also appeals elsewhere in the store – on rolls of toilet paper with his face printed on it.

“We got Biden toilet paper,” Fran Diemer, the store’s clerk says.

“That’s about all our support for Joe Biden.”

Image source, Reuters

The two candidates have had busy schedules leading up to Thursday evening.

Donald Trump held various meetings with his allies in the last week to go over policy points, while President Joe Biden hunkered down at Camp David to prepare with his team before resuming his formal duties.

After the debate, the two look to be wasting no time as they both plan to swiftly head back on the campaign trail.

Biden will be hosting a post-debate rally in Raleigh, North Carolina on Friday, where he is expected to be joined by rappers Fat Joe and E-40, as well as First Lady Jill Biden.

In a statement to media on the event, a Biden campaign official said the invited rappers are "legends of the music industry, who understand the importance of utilising their platforms to ensure their fan base understands the stakes of this election."

Meanwhile, Trump will be hosting his own campaign event in Chesapeake, Virginia, where he promises to "deliver remarks on Joe Biden's incompetent presidency."

If you are new to US politics or just need to remind yourself what all these wonky words mean, we’ve got a few lists to help.

This first list is all about words related to election procedures in the United States.

• Electoral College: The US presidential race is not technically one big vote, but 50 (or more) smaller elections. Each state and territory runs its own election, and then sends a designated number of electors - which is roughly based on its population size - to vote in the Electoral College. There are 538 possible electoral votes up for grab. A candidate needs 270 to become president. Most states allot all of its electors to the candidate who won the most votes, but Maine and Nebraska split electors proportionally.
• State ballots: Each US state and territory creates its own ballot for the presidential election. Voters can chose their preferred candidate on those ballots, but they may also be faced with specific state-level or even local-level elections - such as for governor or mayor. Some ballots also include third-party and independent presidential candidates.
• Delegates: Political parties (Republicans and Democrats) run their own primary elections in each state to decide who will represent them as a presidential candidate. The winners are awarded delegates, who then cast their ballots for the candidates at their national conventions.
• National conventions: Political parties officially name their presidential nominees at a multi-day gathering - part serious meeting and part raucous celebration - called a national convention. This is when state delegates that each primary candidate has been awarded cast their ballots. The winner usually becomes the official nominee on the last night of the convention. The Republican convention, or the RNC, is being held in the city of Milwaukee on 15-18 July. The Democrats’ convention, or DNC, is in Chicago on 19-22 August.
• Ticket: A presidential candidate and their vice-presidential running mate make up a party’s “ticket”.

Stick around for some more US political terms de-mystified.

Earlier this week, I wrote about how voters' concerns about Biden and Trump's age were hanging over this debate.

In the spin room just now, I asked California Governor Gavin Newsom, who is considered part of a newer generation of Democratic leaders, about what Biden could do to win over these voters tonight.

"What he continues to do, and that's deliver," Newsom said.

"It's about ideas, it's about values, it's about principles, and its not about age. That's time of life. It's about state of mind," he said.