The court was considering the unprecedented and consequential question of whether a state court can enforce a rarely invoked, post-Civil War provision of the Constitution to disqualify Trump from returning to the White House.

During more than two hours of argument, the justices asked questions that suggested that t he often deeply divided court could reach a unanimous or near-unanimous decision to reject the challenge to Trump’s eligibility brought by six Colorado voters. Not since the court’s 2000 ruling in Bush v. Gore has the Supreme Court been thrust into such a pivotal role in a presidential election.

Liberal Justice Elena Kagan repeatedly questioned whether one state should be allowed to decide whether a presidential candidate is disqualified. “Why should a single state have the ability to make this determination not only for their own citizens but for the rest of the nation?” she asked, adding, “That seems quite extraordinary, doesn’t it?”

Conservative Justice Amy Coney Barrett agreed, adding that “it just doesn’t seem like a state call.”

Trump is quickly closing in on the GOP nomination, and several justices suggested that a state court ruling initiated by voters in one state to bar him from federal office would throw the presidential race into extreme disarray.

Chief Justice John G. Roberts Jr. predicted that a number of other states would quickly try to disqualify the leading Democratic candidate if the justices allowed the Colorado decision to stand. He called the prospect of a handful of states deciding the presidential election a “pretty daunting consequence.”

Justice Brett M. Kavanaugh worried about disenfranchising voters if the court removed the leading Republican presidential candidate from the ballot. “What about the idea that we should think about democracy, think about the right of the people to elect candidates of their choice, of letting the people decide?” he asked.

In response, attorney Jason Murray, representing the Colorado voters, said, “The reason we’re here is that President Trump tried to disenfranchise 80 million Americans who voted against him, and the Constitution doesn’t require that he be given another chance.”

The high court could announce a decision at any time. Its opinion is expected to resolve the issue in other states with similar challenges to Trump’s eligibility.

Colorado’s top court put its December ruling on hold while the litigation continues. Trump’s name will appear on the state’s already printed March 5 primary ballot.

At issue is Section 3 of the 14th Amendment, which prohibits anyone who previously pledged to support the Constitution as “an officer of the United States” from returning to office if they betrayed their oath by engaging in insurrection.

The challenge to Trump’s candidacy was brought by six Colorado voters — four Republicans and two independents. After a five-day trial, a lower court judge in November concluded that Trump engaged in insurrection when he summoned his supporters to Washington and encouraged an angry crowd to disrupt Congress’s certification of President Biden’s 2020 victory. But the judge also found that Section 3 did not apply to the presidency.

A divided Colorado Supreme Court disagreed and barred Trump from the ballot, prompting his appeal to the Supreme Court. Maine’s secretary of state reached the same conclusion, but her decision is also on hold.

Much of the discussion Thursday centered on differing interpretations of the text and history of the 14th Amendment provision, also known as the disqualification clause, which was initially intended to stop former Confederates from returning to power after the Civil War.

Conservative Justice Clarence Thomas and liberal Justice Ketanji Brown Jackson — two justices who have not often agreed on the most divisive issues before the court — both expressed deep skepticism of the Colorado voters’ view of the scope of the 14th Amendment, agreeing with Roberts’s assessment that the post-Civil War amendment was aimed at limiting the power of the states.

And yet, Roberts said, the Colorado voters seeking to remove Trump from the ballot appear to be trying to use the same amendment to say states have the power to prevent candidates from running for nationwide office.

“That seems to be a position that is at war with the whole thrust of the 14th Amendment and very ahistorical,” Roberts said.

The text of Section 3 does not specify who is supposed to enforce the clause or when it should be invoked.

Trump’s attorney, Jonathan Mitchell, told the justices that Congress, not state courts or officials, enforce the provision and that Trump’s passionate political speech on Jan. 6 did not amount to insurrection. Section 3 does not apply to Trump, they emphasized, because the president is not an “officer of the United States,” which is the term the section uses to discuss potential insurrectionists.

Mitchell pointed to three other sections of the Constitution — the appointments clause, the commissions clause and the impeachment clause — that distinguish between the president and “officers” appointed by the president.

On the other side, leading historians and the Colorado voters working with Citizens for Responsibility and Ethics in Washington have cast doubt on the idea that the framers of Section 3 would have created a loophole for oath-breaking, insurrectionist former presidents.

Murray, the voters’ lead attorney, urged the justices not to create a “special exemption” from the disqualification clause for Trump.

The former president’s eligibility is not the only question before the court that could affect Trump’s political future. He is expected to asked the Supreme Court to reverse a ruling this week from the U.S. Court of Appeals for the D.C. Circuit that said he is not protected by presidential immunity from being prosecuted for trying to block Biden’s 2020 victory.

The justices separately have said they will review the validity of a law that was used to charge hundreds of people in connection with the Jan. 6 riot and is also a key element of Trump’s four-count federal election obstruction case in Washington.

In a sign of the significance of the case before the Supreme Court on Thursday, the courtroom was filled with many guests of the justices, high-profile visitors and dozens of journalists. Among those in attendance was Rep. Jamie Raskin (D-Md.), who helped lead the impeachment proceedings against Trump after the attack on the U.S. Capitol.

Trump listened to the argument from Mar-a-Lago in Florida and called it “a beautiful thing to watch, in many respects.”

“I thought the presentation today was a very good one,” Trump said at a news conference after the arguments concluded. “I think it was well received. I hope it was well received.”

This is a developing story. It will be updated.

Rachel Weiner, Amy B Wang and Isaac Arnsdorf contributed to this report.