The 14th Amendment clause that attorneys argue should disqualify former President Trump from Colorado’s 2024 ballot can apply to presidents, an expert witness testified Wednesday, going directly against the Trump campaign’s arguments.

Attorneys called on a 14th Amendment expert in the hearing’s third day, Indiana University law professor Gerard Magliocca, to lay out exactly how to define “insurrection” and how it should apply to presidents.

What insurrection means is at the center of the case, as Trump campaign attorneys argue that the 14th Amendment’s third section does not apply to Trump both because his actions don’t fit the term “insurrection” and because the clause can’t apply to presidents due to specific readings of the amendment.

The plaintiff’s lead attorney, Eric Olson, has argued the Colorado case has four basic components: Trump took an oath as an officer of the U.S., the Capitol attack was an insurrection, Trump engaged in that insurrection and Colorado’s secretary of state can be ordered by the court to keep him off the state’s ballot because of it.

Magliocca’s expert testimony Wednesday was intended to build the first two pillars of the case’s argument. Separate expert testimony Tuesday focused on the third pillar, regarding Trump’s involvement with right-wing extremist groups.

Magliocca explained that the 14th Amendment’s third section was enacted after the Civil War as a way to keep Confederate-supporting politicians out of office unless they were given amnesty by Congress.

But he was clear that the section was not intended to only fit the Civil War, and that it could also apply to future “insurrections.”

Magliocca defined an insurrection, using a number of historical legal citations, as “any public use of force or threat of force, by a group of people to hinder or prevent the execution of the law.”

The plaintiff’s attorneys are expected to argue that the Jan. 6 attack on the Capitol fits that definition, and separately, that Trump’s actions on and before the attack fall under giving “aid or comfort” to those who participated in it.

An expert witness for the Trump campaign, legal scholar Robert Delahunty, argued the opposite in written testimony. He said that the term “insurrection,” when used in the 14th Amendment, is too vague and that the clause doesn’t even apply to the presidency.

That argument hinges on the definition of “office” when used in the text. The third section of the amendment specifically names senators and representatives as beholden to the section, but also “any office, civil or military, under the United States.” 

Delahunty argued that “any office” does not include the presidency, while Magliocca said the opposite.

“It would have been odd to say that people who had broken their oath to the Constitution by engaging in insurrection were ineligible to every office in the land except the highest one,” Magliocca said.

He argued that any person who took an oath of office fell under the umbrella of holding “office” for the purposes of the 14th Amendment.

Plaintiffs also called on a second expert witness Wednesday, Deputy Director of the Colorado Secretary of State Office Hilary Rudy, about the office’s role in potentially taking Trump off the presidential ballot.

“It is the secretary’s position that if we have affirmative knowledge that a candidate is ineligible for office then we will not certify them to the ballot,” Rudy said.

In the case’s opening arguments Monday, the attorneys representing the Colorado Republican Party and Trump’s lawyers argued that the former president was simply exercising his free speech rights to warn about election results he did not believe were legitimate.

They also claimed that the specific 14th Amendment clause was untried in more than 150 years for this purpose and is being misread.

“This is a legal Hail Mary by the Democrats,” said Mike Davis, an attorney who appeared with representatives of the Trump campaign outside court before the trial began. “This case is going to fail.” 

Similar cases are being considered in Minnesota and Michigan — the latter of which is notably a key swing state. It is likely one of these cases will land before the Supreme Court, which has never ruled on the 14th Amendment’s “insurrection clause.” Three of the current sitting justices were appointed by Trump during his first term.