The Supreme Court seemed poised on Thursday to issue a lopsided decision rejecting a challenge to former President Donald J. Trump’s eligibility to hold office again.
Justices across the ideological spectrum expressed skepticism about several aspects of a ruling from the Colorado Supreme Court that Mr. Trump’s conduct in trying to subvert the 2020 race made him ineligible to hold office under a constitutional provision that bars people who have sworn to support the Constitution and then engaged in insurrection.
Not since Bush v. Gore, the 2000 decision that handed the presidency to George W. Bush, has the Supreme Court assumed such a direct role in a presidential contest. This time, though, it seemed the justices were not prepared to determine the outcome of the election.
The ruling is likely to resolve not only whether Mr. Trump may appear on the Colorado primary ballot but also whether he is eligible to run in the general election. Indeed, the decision in the Colorado case will almost certainly apply to any other state where Mr. Trump’s eligibility to run has been challenged, including Maine, where the state’s top elections official ruled he should be excluded from the ballot.
There was very little discussion of the Jan. 6 assault on the Capitol or of Mr. Trump’s role in it. But a majority of the justices indicated that they were prepared to rule that individual states may not disqualify candidates in a national election unless Congress first enacts legislation allowing them to do so.
Some justices also seemed open to two other arguments: that the post-Civil War prohibition at issue, Section 3 of the 14th Amendment, bars candidates from holding office, as opposed to running for it, and that the president is not among the officials to whom the provision applies.
Chief Justice John G. Roberts Jr. asked a series of questions reflecting what seemed to be an emerging consensus: that the 14th Amendment was not meant to permit individual states to determine whether a candidate was ineligible.
“The whole point of the 14th Amendment was to restrict state power, right?” he asked, adding that the challengers’ contrary argument was “a position that is at war with the whole thrust of the 14th Amendment.”
Chief Justice Roberts noted that the challengers’ position would have empowered the former Confederate states to determine whether candidates were disqualified from holding federal office. The 14th Amendment was adopted to constrain states’ rights and empower the federal government, the chief justice said, and it would be “the last place that you’d look for authorization for the states, including Confederate states, to enforce — implicitly authorize to enforce — the presidential election process.”
Justice Elena Kagan, a liberal, also expressed concern about granting individual states too much power over national elections.
“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,” she told Jason C. Murray, a lawyer for the Colorado voters challenging Mr. Trump’s eligibility. She added, “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?”
Justice Ketanji Brown Jackson, another liberal, said she doubted that the drafters of Section 3 intended to create “disuniformity in this way, where we have elections pending and different states suddenly saying, you’re eligible, you’re not.”
Justice Brett M. Kavanaugh reviewed what he said was the relevant history and concluded that “Congress has the authority here, not the states.”
He added that the challengers’ position — that Mr. Trump may not be on the ballot — was in tension with democratic principles, especially given the provision’s indeterminate quality.
“In trying to figure out what Section 3 means and kind of to the extent it’s elusive language or vague language,” he said, “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? Because your position has the effect of disenfranchising voters to a significant degree.”
Mr. Murray, the challengers’ lawyer, said Section 3 was meant to protect democracy.
“The framers of Section 3 knew from painful experience that those who had violently broken their oaths to the Constitution couldn’t be trusted to hold power again because they could dismantle our constitutional democracy from within, and so they created a democratic safety valve,” he said. “President Trump can go ask Congress to give him amnesty by a two-thirds vote. But, unless he does that, our Constitution protects us from insurrectionists.”
Chief Justice Roberts expressed concern that allowing the challenge to Mr. Trump’s eligibility would prompt other ones.
“Insurrection is a broad, broad term,” he said. “And if there’s some debate about it, I suppose that will go into the decision and then eventually, what, we would be deciding whether it was an insurrection when one president did something as opposed to when somebody else does something else. And what do we do? Do we wait until near the time of counting the ballots and sort of go through which states are valid and which states aren’t?”
He said this was a recipe for chaos.
“I would expect that a goodly number of states will say whoever the Democratic candidate is, you’re off the ballot,” he said. “For the Republican candidate, you’re off the ballot. And 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 case is just one of several involving or affecting Mr. Trump on the court’s docket or approaching it.
An appeals court ruled on Tuesday that Mr. Trump was not immune from prosecution for his role in the Jan. 6 attack on the Capitol, giving the former president until Monday to seek a stay of that ruling from the Supreme Court. And the justices have already agreed to decide on the scope of a central charge in the federal election-interference case against Mr. Trump, with a ruling by June.
Thursday’s case arose from a December ruling from the Colorado Supreme Court disqualifying Mr. Trump from the state’s Republican primary ballot based on Section 3 of the 14th Amendment. The provision was adopted after the Civil War to bar insurrectionists who had taken an oath to support the Constitution from holding office.
The provision says: “No person shall be a senator or representative in Congress, or elector of president and vice president, or hold any office, civil or military, under the United States, or under any state, who, having previously taken an oath, as a member of Congress, or as an officer of the United States, or as a member of any state legislature, or as an executive or judicial officer of any state, to support the Constitution of the United States, shall have engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof.”
It adds, “But Congress may, by a vote of two-thirds of each House, remove such disability.”
A Colorado trial judge ruled that Mr. Trump had engaged in insurrection but accepted his argument that Section 3 did not apply to the president or to the office of the presidency.
The Colorado Supreme Court affirmed the first part of the ruling — that Mr. Trump had engaged in an insurrection, including by setting out to overturn the result of the 2020 presidential election; trying to alter vote counts; encouraging bogus slates of competing electors; pressuring the vice president to violate the Constitution; and calling for the march on the Capitol.
But the majority reversed the part of the decision that said Section 3 did not apply to the presidency.
“President Trump asks us to hold,” the majority wrote in an unsigned opinion, “that Section 3 disqualifies every oath-breaking insurrectionist except the most powerful one and that it bars oath breakers from virtually every office, both state and federal, except the highest one in the land. Both results are inconsistent with the plain language and history of Section 3.”
Mr. Trump had attacked the Colorado court’s ruling on at least a half-dozen grounds, though their unifying theme is that the election should be decided by the voters.
“The court should put a swift and decisive end to these ballot-disqualification efforts, which threaten to disenfranchise tens of millions of Americans and which promise to unleash chaos and bedlam if other state courts and state officials follow Colorado’s lead and exclude the likely Republican presidential nominee from their ballots,” Mr. Trump’s brief said.
The six Colorado voters who prevailed in the case in that state urged the justices not to give in to what they suggested were threats of political violence from a candidate they said had demonstrated a propensity for it.
“The thrust of Trump’s position is less legal than it is political,” the voters’ brief said. “He not-so-subtly threatens ‘bedlam’ if he is not on the ballot. But we already saw the ‘bedlam’ Trump unleashed when he was on the ballot and lost.”
Mr. Trump’s primary legal argument in the case, Trump v. Anderson, No. 23-719, was that Section 3 does not apply to him because the president is not among the officials covered by the provision. “The president is not an ‘officer of the United States’ as that term is used in the Constitution,” his brief said.
That position intrigued some justices and seemed to baffle some others. Justice Sonia Sotomayor called it “a bit of a gerrymandered rule, isn’t it, designed to benefit only your client,” as Mr. Trump, unlike almost every other president, had not sworn to support the Constitution in another official capacity.
Several justices asked questions suggesting that the challenge to Mr. Trump’s eligibility was premature as Section 3 disqualifies people subject to it from holding office — not from seeking it. If Mr. Trump were elected, they said, Congress could remove the disqualification before his term began.
While the justices did not spend much time discussing whether the Jan. 6 attack was an insurrection, Jonathan F. Mitchell, a lawyer for Mr. Trump, made a point of denying it.
“This was a riot,” he said. “It was not an insurrection. The events were shameful, criminal, violent, all of those things, but did not qualify as insurrection as that term is used in Section 3.”
Justice Brett M. Kavanaugh said the difficulty of determining what counts as an insurrection was another reason to require congressional action.
“The term insurrection jumps out,” he said. “And the questions are: What does that mean? How do you define it? Who decides whether someone is engaged in it?”
He added, “That tells you Congress has the primary role here.”