WASHINGTON — The Supreme Court on Thursday hears a momentous case about whether former President Donald Trump can be kicked off the Republican primary ballot in Colorado because of his actions trying to overturn the 2020 election results.

Oral arguments in front of the nine justices begin just after 10 a.m. and could last for several hours.

The case could have broad implications if Trump loses, because other states could follow suit, placing hurdles in the way of his attempt to regain the presidency this fall. State officials in conservative-controlled governments have also warned they could seek to remove President Joe Biden from the ballot in response.

The Supreme Court, which has a 6-3 conservative majority, will tackle several novel and consequential legal issues concerning Section 3 of the Constitution’s 14th Amendment, enacted in the wake of the Civil War.

Under that provision, aimed at preventing former Confederates from returning to power in the U.S. government, anyone who had previously served as an “officer of the United States” and then “engaged in insurrection” would be barred from holding federal office.

The Colorado Supreme Court ruled in December that Trump could be thrown off the Republican primary ballot but put its decision on hold while he appealed.

Trump, who has often attended recent court hearings in the various civil and criminal cases he is involved in, is not expected to be in the courtroom Thursday.

The legal challenge was filed on behalf of six Colorado residents, four of whom are Republicans, by the left-leaning government watchdog group Citizens for Responsibility and Ethics in Washington and two law firms.

They allege in court papers that Trump “intentionally organized and incited a violent mob to attack the United States Capitol in a desperate attempt to prevent the counting of electoral votes cast against him.”

Trump’s lawyers have offered several grounds for tossing out the lawsuit. They argue that the president is not an officer of the U.S., that Trump did not engage in insurrection and that only Congress can enforce Section 3.

The justices will hear from lawyers representing Trump, the Colorado plaintiffs and Colorado Secretary of State Jena Griswold, the state’s top elections official.

The conservative majority includes three justices — Neil Gorsuch, Brett Kavanaugh and Amy Coney Barrett — appointed by Trump. Another conservative, Justice Clarence Thomas, has faced scrutiny over his involvement in the case because of the role of his wife, conservative political activist Virginia “Ginni” Thomas, in backing Trump’s challenge to the election results. Some Democrats had asked Thomas to recuse himself.

Despite the court’s conservative majority, it has regularly handed losses to Trump since he left office.

Interest in the Colorado case was heightened when Maine’s top election official concluded that Trump was ineligible to appear on the Republican primary ballot in that state, too. Like the Colorado dispute, that case was put on hold, meaning Trump remains on the ballot for now in both states.

The Supreme Court is hearing the Colorado case on an expedited schedule, with a ruling expected within weeks. Colorado is one of more than a dozen states that have their primary elections on March 5.