The United States' highest court is considering its most significant election case in decades: Can Donald Trump be disqualified from running for the White House again?
The unprecedented case against the former president, and current Republican frontrunner, hinges on the argument that he cannot return to office because he engaged in insurrection through the January 6 Capitol attack.
The Supreme Court justices appear sceptical of that argument so far, using a public hearing in Washington to raise concerns about the potential flow-on effects.
But while the nation waits for their decision, Mr Trump's fate hangs in the balance.
What is this case about and what is the 14th amendment?
The case centres on a Civil War-era part of the US constitution, originally aimed at preventing former officials in the Confederacy (the southern states which lost the war) from returning to positions of power.
Section three of the 14th amendment, which had previously been long-ignored, prohibits someone from assuming public office if they've previously taken an oath to support the constitution, but then "engaged in insurrection".
A group of Republican and unaffiliated voters in Colorado argued Donald Trump did just that on January 6, 2021, when he told his supporters to "fight like hell" shortly before they stormed the Capitol building.
The voters made the case that he should therefore be disqualified from running in the state's Republican primary, which helps to decide who will represent the party at the presidential election.
The Supreme Court in Colorado agreed, finding Mr Trump engaged in insurrection and was ineligible to contest the primary.
"We do not reach these conclusions lightly," the justices in the majority of the 4-3 ruling wrote.
"We are mindful of the magnitude and weight of the questions now before us."
Mr Trump vowed to appeal against both the Colorado ruling, and a decision of Maine's top election official soon after that he was disqualified from running in that state too.
"On the flip side, there are courts in Minnesota and Michigan that came to the opposite conclusion about how the 14th amendment applies," Nancy Marcus said, an associate professor at California Western School of Law.
"So what happens when you have that kind of tension and conflict between court rulings that are interpreting the constitution, is the Supreme Court is stepping in."
What did Trump's attorneys argue?
Mr Trump's lawyers largely focused on a claim that the section of the constitution in question does not apply to the president of the United States.
The text states that no one can "hold any office, civil or military" if they’d previously taken an oath "as an officer of the United States" to support the constitution, but then engaged in insurrection.
Mr Trump's team argues the text doesn't apply to him, because it does not specifically mention the role of president, and the position is not technically an "officer".
His attorney also told the court that Congress would have to pass legislation to enforce section three before it could be used.
And he denied that January 6 amounted to an insurrection, describing it as a "riot".
"For an insurrection, there needs to be an organised, concerted effort to overthrow the government of the United States through violence," Mr Trump’s attorney Jonathan Mitchell said.
"The events were shameful, criminal, violent, all of those things, but did not qualify as insurrection as that term is used in section three."
The lawyer representing the Colorado voters, Jason Murray, rejected that argument, describing January 6 as a "violent assault" that was incited by the-then president to disrupt the peaceful transfer of power.
But the Supreme Court's nine justices spent little of the roughly two-hour long hearing on the issue of whether an insurrection had occurred, instead focusing on more technical aspects of the case.
Did the court indicate how it will rule?
The hearing was known as oral arguments. Questions posed by the justices to lawyers on both sides can provide insights into which way they might be leaning.
The Supreme Court has a 6 – 3 conservative majority, with three of the justices having been appointed by Mr Trump.
But the overall lines of inquiry suggested there was fairly broad scepticism of the Colorado court's ruling.
"I think that the question that you have to confront is why a single state should decide who gets to be president of the United States," liberal justice Elena Kagan told Mr Murray.
"In other words, this question of whether a former president is disqualified for insurrection... it sounds awfully national to me."
Chief Justice John Roberts suggested that if Colorado’s decision was upheld, other states would follow with their own disqualification cases.
"I would expect that a goodly number of states will say whoever the Democratic candidate is, you're off the ballot and others, for the Republican candidate, you're off the ballot," he said.
"It will come down to just a handful of states that are going to decide the presidential election.
"That's a pretty daunting consequence."
The Supreme Court has not been asked to weigh into such a consequential presidential election case since it ruled against a recount in 2000, effectively handing victory to George W. Bush.
Professor Marcus said Mr Trump's campaign was not the only issue at stake in 2024.
"Another implication of this case, a really serious one, is the reputation of the Supreme Court itself," she said.
"Polling shows that the public is more distrustful of the Supreme Court than it's ever been, so it does risk being viewed as a politically biased institution."
When will the court issue its decision?
The Supreme Court follows a similar schedule every year, and its opinions are usually handed down by the end of June.
But there's an added sense of urgency to this case, with Colorado's primary due to be held on March 5.
"I'm hopeful the justices will look at the facts with an open mind," Colorado’s top election official, Jena Griswold said.
"And make a big decision for the United States to protect our democracy from the danger of another Trump candidacy and another Trump presidency."
Speaking from his Mar-a-Lago resort in Florida, Mr Trump described the hearing as a "beautiful thing to watch", adding that his lawyer's arguments were "very strong".
"Can you take the person that's leading everywhere and say, 'Hey, we're not going to let you run?'" he said.
"You know, I think that's pretty tough to do, but I'm leaving it up to the Supreme Court."
The court could soon be asked to weigh into another of Mr Trump's legal cases, after the former president said he would appeal against a decision that he was not immune from being criminally prosecuted over charges of trying to overturn the 2020 election.
It could be another momentous decision in what has already become an election year like no other.