DENVER (AP) — The videos playing in a Colorado courtroom were both chilling and, by now, familiar — a violent mob, with some wearing tactical gear, smashing through the U.S. Capitol, attacking police officers and chanting “Hang Mike Pence!”

Now, lawyers on day two of the weeklong hearing are arguing whether the infamous events of Jan. 6, 2021 constituted an insurrection under a rarely used clause of the U.S. Constitution that they are trying to use to disqualify former President Donald Trump from the 2024 ballot. The hearing in Colorado is one of two this week — with the second before the Minnesota Supreme Court on Thursday — that could end up before the U.S. Supreme Court, which has never before ruled on the Civil War-era provision in the 14th Amendment.

Tuesday’s witnesses are expected to include an expert in right-wing violence and an expert on Section Three of the 14th Amendment, which has only been used a handful of times since it was adopted in 1868. The testimony will get to the heart of the thorny legal issues the case raises — what constitutes an “insurrection” and how can the extreme political penalty of being barred from office be applied?

The plaintiff’s lawyers contend the provision is straightforward and that Trump is clearly disqualified from the presidency, just as if he were under the Constitution’s minimum age for the office of 35.

Trump’s lawyers argue that there remains a host of questions — did the authors even mean for the provision to apply to the presidency, which is not mentioned in the amendment although “presidential and vice presidential electors” are, along with senators and members of the House of Representatives? Did it target those who simply exercised free speech to support unpopular causes or only those who took up arms?

Scott Gessler, Trump’s lead Colorado attorney and a former Republican secretary of state there, dismissed the lawsuit as “anti-democratic” and noted that one other presidential candidate — socialist labor organizer Eugene Debs — even ran for the office from prison without people trying to use Section Three to disqualify him.

“If they don’t like President Trump, they need to get involved in an election,” Gessler said after the first day. “But what they’re trying to do is short-circuit an election.”

On Monday, the Colorado testimony began with details about the Jan. 6 assault that was intended to stop Congress from certifying President Joe Biden’s election win.

Lawyers representing six Republican and unaffiliated Colorado voters argued that Trump’s violent rhetoric preceding the attack makes him culpable, and barred from the presidency again under that clause prohibiting anyone who swore an oath to the constitution and then “engaged in insurrection” against it from holding office.

“We are here because Trump claims, after all that, that he has the right to be president again,” attorney Eric Olson said. “But our Constitution, the shared charter of our nation, says he cannot do so.”

Trump’s legal team and presidential campaign assailed the lawsuit as little more than an attempt by Democrats to derail his attempt to reclaim his old job. Trump is so far dominating the Republican presidential primary, and the lawsuits to block him were organized by two separate liberal groups.

Seeking to underscore that point, Trump’s campaign said before the hearing that it had filed a motion for District Court Judge Sarah B. Wallace to recuse herself because she had made a $100 donation in October 2022 to the Colorado Turnout Project, a group whose website says it was formed to “prevent violent insurrections” such as the Jan. 6 attack. Wallace declined to do so.

She was appointed to the bench in August of that year by Gov. Jared Polis, a Democrat. Wallace said she didn’t recall the donation until the motion was filed and has no preconceptions about the legal issues in the case.

“I will not allow this legal proceeding to turn into a circus,” she said.