Six Colorado voters filed a lawsuit on Wednesday seeking to keep former President Donald J. Trump off the state’s ballots under the 14th Amendment, which says anyone who “engaged in insurrection or rebellion” against the Constitution after taking an oath to defend it is ineligible to hold office.
The lawsuit, which was filed in a state district court in Denver with the help of the watchdog group Citizens for Responsibility and Ethics in Washington, demands that the Colorado secretary of state not print Mr. Trump’s name on the Republican primary ballot. It also asks the court to rule that Mr. Trump is disqualified in order to end any “uncertainty.”
The theory that the 14th Amendment disqualifies Mr. Trump has gained traction among liberals and anti-Trump conservatives since two prominent conservative law professors argued in an article last month that his actions before and during the Jan. 6, 2021, attack on the Capitol constituted engagement in an insurrection. But it remains a legal long shot. Mr. Trump would surely appeal any ruling that he was ineligible, and a final decision could rest with the Supreme Court, which has a conservative supermajority that includes three justices he appointed.
A spokesman for Mr. Trump did not respond to a request for comment.
Jena Griswold, the Colorado secretary of state, said in a statement, “I look forward to the Colorado court’s substantive resolution of the issues, and am hopeful that this case will provide guidance to election officials on Trump’s eligibility as a candidate for office.”
The plaintiffs are Republican and unaffiliated voters who argue that Mr. Trump is ineligible and that they will be harmed if he appears on primary ballots. They aim to ensure “that votes cast will be for those constitutionally qualified to hold office, that a disqualified candidate does not siphon off support from their candidates of choice, and that voters are not deprived of the chance to vote for a qualified candidate in the general election,” the suit says.
Similar efforts are unfolding in other states. Last month, the liberal group Free Speech for People wrote to the secretaries of state of Florida, New Hampshire, New Mexico, Ohio and Wisconsin, urging them not to include Mr. Trump on ballots. And an obscure presidential candidate, John Anthony Castro, a Republican, has sued in New Hampshire.
These attempts are separate from the criminal cases against Mr. Trump. They do not depend on his being convicted, and convictions would not trigger disqualification.
The legal questions instead include what counts as engaging in an insurrection, who has standing to challenge Mr. Trump’s eligibility and who has the authority to enforce his disqualification if he is disqualified.
“Section 3 of the 14th Amendment is old — it has not been truly stress-tested in modern times,” said Jessica Levinson, a professor at Loyola Law School who specializes in election law. “There are some big forks in the road where you can argue both ways.”
The first fork in the Colorado case will be whether individual voters have the right to sue. Challenges to a candidate’s eligibility — on any basis, not just the 14th Amendment — often come from opposing candidates, who are directly affected by the challenged candidate’s presence.
Derek Muller, a professor at Notre Dame Law School, emphasized that standing requirements are looser in state courts than in federal courts, especially when it comes to voters’ ability to challenge candidates’ eligibility. But Richard Collins, an emeritus professor of law at the University of Colorado, said that the Colorado Supreme Court had become increasingly restrictive in its interpretation of standing.
And beyond standing, Professor Muller said, a big hurdle could be “ripeness”: Because candidates haven’t formally filed for ballot access yet, a judge could decide that the legal questions are not ready for review.