Image source, Getty Images

Trump's defence lawyer Jonathan Mitchell tells the court that Section 3 doesn't apply to Donald Trump, because it doesn't apply to the office of the presidency and because courts do not have the power to bar a candidate from running for president.

Mitchell said Congress would need to pass legislation enabling courts that power.

Justice Sonia Sotomayor, one of the three liberal justices, responds: "History proves a lot to me, and to my colleagues, generally. And there's a whole lot of examples of states relying on Section 3 to disqualify insurrectionists for state offices," she says.

Sotomayor says Mitchell is basically asking the justices to go "three steps" beyond direct interpretations of Section 3 to accept his arguments,

"You want us now to say it means that Congress must permit states or require states to stop insurrectionists from taking the state office," Sotomayor asks. "This is a complete pre-emption in a way that's very rare."

Kayla Epstein
US reporter

Clarence Thomas, one of the most conservative justices on the court, jumps in with the first questions.

They centre on whether the key bit of the Constitution on which this case hinges - Section 3 of the 14th Amendment - is "self-executing". That basically means whether it needs any accompanying legislation passed by Congress to give the amendment teeth.

Trump's lawyer Mitchell argues Section 3 is not "self-executing". Clarence says if that's the case, then what is the role of the state in determining whether or not a candidate is disqualified under the insurrection clause?

Or is it entirely up to Congress to implement the disqualification? Thomas asks.

Mitchell replies that yes, Trump's team believes it is entirely up to Congress.

Sam Cabral
Reporting from the Supreme Court

The justices are asking whether a secretary of state has the power to remove a candidate based on Section 3 if they admit to being an insurrectionist.

Trump's lawyer Mitchell says that no secretary of state has this authority "even if the candidate is an admitted insurrectionist".

Only Congress can enforce Section 3, he argues, and only by removing a candidate after they have been elected - not by removing them from the ballot before the election.

He claims this happened frequently in the post-Civil War era in the case of former Confederates.

Sam Cabral
Reporting from the Supreme Court

Jonathan Mitchell, the attorney representing Donald Trump, is laying out the main arguments for why Donald Trump cannot be disqualified from the ballot in the presidential race.

He says the president is not "an officer of the United States", and therefore Section 3 cannot apply him. (Section 3 of the 14th Amendment bars "an officer of the United States" who has taken the oath of office and engaged in insurrection from holding public office).

Mitchell further argues that Section 3 cannot be used to exclude a candidate for president and a state cannot exclude a candidate based on the clause.

"I welcome the court's questions," he says.

The justices of the Supreme Court have taken their seats.

The marshal of the court - effectively its chief of police - has just struck her gavel and greeted the nine jurists.

"Oyez! Oyez! Oyez!" she proclaims, as part of her traditional declaration to usher in the session.

And we're off.

Brandon Drenon
Reporting from Washington DC

Trump's lawyers have made multiple now-rejected arguments as to why Section 3 of the 14th Amendment in the US Constitution does not apply to him.

Section 3 bars "an officer of the United States" who has taken the oath of office and engaged in insurrection from holding public office.

Trump's lawyers have argued, however, that as president he was "not an officer of the United States" defined under Section 3. So, they say, it doesn't apply to him.

The other defence Trump's lawyers have made is that the question of eligibility for presidency is not an issue for the courts to resolve. Instead, they say the Constitution reserves that right for Congress.

Trump's lawyers have also tried to say that his language on 6 January is protected free speech and that his comments that day don't make him culpable for engaging in an insurrection.

Robert Tsai, a constitutional law professor from Boston University, told the BBC: "I think Trump's lawyers are going to have a hard time figuring out what gets five votes" - the total votes needed for a simple majority among the nine justices.

"What's going to be the opinion that looks the least damaging and overrules the Colorado Supreme Court," Tsai said - that's what the Supreme Court judges are going to be looking for, he said.

Anthony Zurcher
BBC North America correspondent

The court’s decision in this case will likely turn on how a majority of the justices interpret the provision of the 14th Amendment to the US Constitution that bans federal officials who "engaged in insurrection or rebellion" against the government from holding public office.

The justices will have to determine if this provision applies to US presidents or only members of Congress and other lower-level federal "officers of the United States".

They may look at how the term is used elsewhere in the Constitution, as well as what the framers of the 14th Amendment may have been thinking when they devised the language.

The Colorado trial court dismissed the case on these grounds, before it was reversed by the state’s Supreme Court.

The justices may also have to decide whether the language of the amendment is "self-executing" – that is, whether it was not necessary for Congress to pass accompanying legislation to give the amendment teeth.

Since no such law was enacted, Trump’s lawyers have contended that the amendment’s ban is unenforceable.

These are the two most prominent lines of argument that could give the Supreme Court an alluring off-ramp in this case, essentially allowing it to throw out Colorado’s ruling on more technical grounds.

Image source, Reuters

Norma Anderson is a Republican who says that her childhood memories of World War Two inspired her to sue to remove Trump from the ballot.

With the help of the advocacy group Citizens for Responsibility and Ethics in Washington, she and five others were the ones who brought this original case to Colorado, suing to have Trump taken off the state's primary ballot.

She told NPR that when watching the Capitol riot unfold she thought "they're trying to overthrow the government".

Anderson was the first woman to serve as majority leader in both chambers of Colorado’s legislature, and told CNN that she supports Nikki Haley, who would be the first woman president of the US if she makes it all the way to the November election.

She is the lead plaintiff and the one who will be remembered for the case, known as Trump v Anderson.

Sam Cabral
Reporting from the Supreme Court

Reporting from the Supreme Court is all about having a keen ear.

There are a few assigned seats inside the court’s press section - but reporters are seated behind a big black curtain that obstructs their view.

That means, just like those of you following along on the court’s live audio feed - which you'll be able to access by pressing play at the top of this page - we are making educated guesses about who is speaking.

It has become a little easier to identify each justice by their voice in recent years, with four women of varied backgrounds now sitting on the court, but the justices are not always easy to differentiate.

No electronic devices are allowed in the court, so we take notes in the old-fashioned way - pen and pad.

This hearing is scheduled to last at least 80 minutes - 40 minutes for the attorney representing Donald Trump, 30 minutes for the attorney representing the six Colorado voters who sued him and 10 minutes for the Colorado solicitor general on behalf of her state.

US media expect the arguments to run about two hours. It begins at 10:00 local time (15:00 GMT).

Brandon Drenon
Reporting from Washington DC

Two lower courts have already found that Donald Trump can be disqualified from re-running for office because of his involvement in the 6 January insurrection.

It was another legal setback for the former president, who is already battling a string of legal cases.

However, legal experts say the Supreme Court is more likely to rule in favour of Trump this time.

"It cannot be that the national presidency for candidacy is determined on a state by state basis," NYU constitutional law professor Samuel Issacharoff told the BBC. "That would be a break down of democratic order."

"I suspect that institutional caution on their part will impel them towards not upholding the disqualification of Donald Trump,"

Issacharoff thinks the Supreme Court will overrule the lower court's decision by finding a procedural flaw that nullifies the case altogether, rather than making a direct ruling, to avoid "tremendous political backlash".

"The Supreme Court is being asked to define the boundaries of democracy," Issacharoff said.

"That is as hard a task for them as one can imagine."

Anthony Zurcher
BBC North America correspondent

For the first time since Bush vs Gore in 2000, the US Supreme Court is caught in the midst of a high-stakes presidential election drama. (Bush vs Gore was a landmark legal decision in 2000 that settled a dispute over an election recount in Florida.)

It’s probably the last place the nine justices want to be.

At a time when public approval of the high court is near all-time lows, the court now has to render a decision that is likely to make a large percentage of the American people unhappy.

And that may be an understatement. Donald Trump has said that if he is successfully removed from the Colorado ballot, and other states follow suit, it will unleash "chaos and bedlam" in America.

Sam Cabral
Reporting from the Supreme Court

We're about 45 minutes away from what will be a historic hearing before the Supreme Court - but a crowd has gathered outside.

A gaggle of reporters with their cameras have flocked at the court steps, which are barricaded off.

A tight security cordon is marshalling members of the public and the press in a narrow queue to the front entrance.

Protesters - many of whom are dressed in black - are also here, making their voices heard.

"Kick Trump off the ballot! No insurrectionists on the ballot!" says one as I pass by.

Their black placards with white lettering label Donald Trump a "traitor" and a "mob boss".

Since yesterday, people have already been queuing up to watch this historic case.

"This is a landmark decision, and I want to be in the room where it happens to quote Hamilton," said one of them, Susan Acker from Cincinnati, Ohio.

Image source, EPA

On 19 December, the Colorado Supreme Court said it found "clear and convincing evidence that President Trump engaged in insurrection".

It said Donald Trump must be removed from its Republican primary ballot because of Section 3 of the 14th Amendment, external, which disqualifies people who engage in "insurrection or rebellion" from holding federal office.

It was the first time Section 3 had been used to disqualify a presidential candidate.

The lengthy 213-page ruling , externalsaid Trump's actions in the build-up to 6 January 2021 did constitute insurrection.

Then, later that month, Maine also blocked Trump from its ballot. Unlike in Colorado, where the top court ruled, in Maine it was decided by the top electoral official because of a quirk in its constitution.

Secretary of State Shenna Bellows, a Democrat, issued a 34-page ruling that said Trump must be removed from its Republican primary ballot because of Section 3

Bellows, an elected official, was accused of making a politically motivated decision by the Trump campaign. She denied this and said it was "thorough and based on the rule of law".

Francesca Gillett
Live reporter, Washington DC

Welcome to our live coverage, as the US Supreme Court will today hear a historic case to determine whether Donald Trump can run for president this year.

Last month, Colorado's top court decided to strike Trump off its ballot in the presidential race, ruling that he engaged in insurrection for his alleged role in the 6 January Capitol attack. The court ruled that under a clause in the US Constitution, that makes him ineligible for president.

Trump is appealing that ruling - and today the nine Supreme Court justices will hear his arguments.

It's uncharted legal waters so we'll have our ears glued to the hearing - which begins at 10:00 local time (15:00 GMT) - to bring you the key moments.

Unless the justices rule against Trump, he looks likely to challenge Democratic President Joe Biden in November. We've got more about the case here.