University of St. Thomas School of Law professor Michael Stokes Paulsen co-authored the article. (University of St. Thomas/The Minnesota Star Tribune)

A constitutional law professor at the University of St. Thomas has co-authored an article igniting a national debate about whether the U.S. Constitution bars President Donald Trump from being on the ballot next year.

Michael Stokes Paulsen, along with William Baude of the University of Chicago, wrote a 126-page draft article that has gone gangbusters online even though it won't be printed in the University of Pennsylvania Law Review until next year.

Baude and Paulsen say the Constitution's Section Three, Article 14, a Civil War-era provision, forbids former office holders who participate in insurrection or rebellion from holding office again.

"Donald Trump cannot be president — cannot run for president, cannot become president, cannot hold office — unless two-thirds of Congress decides to grant him amnesty for his conduct on Jan. 6," Baude said, summarizing the article in an interview with the New York Times last month.

Paulsen declined an interview request about the draft article that a Washington Post opinion piece said tossed a "legal grenade into our politics." Columnist Greg Sargent predicted various legal challenges throughout the country to Trump's name on the ballot.

Minnesota Secretary of State Steve Simon said he expects the U.S. Supreme Court will be asked sooner rather than later whether to allow Trump on the ballot. On Wednesday, a Denver group filed a lawsuit in Colorado, claiming the clause bars Trump.

Simon, who took two courses from Paulsen when he was in law school at the University of Minnesota in the 1990s, said it's extraordinary for a law review article to receive so much attention.

Simon said his office has received hundreds of inquiries about the legality of Trump being on the ballot. "Our response has been: When it comes to questions of eligibility, that's left for the courts to determine, not me or anyone in our office," Simon said.

In Minnesota, state law broadly allows "any person" to challenge the eligibility of a candidate on the grounds that an error has occurred or is about to, Simon said.

The Minnesota ballot challenge was successfully used in 2016 when the state Supreme Court determined that Rep. Bob Barrett, a Republican who claimed he had a rental in Taylors Falls, was ineligible to run because he didn't live in his district.

The deadline in Minnesota for challenging ballot eligibility is 71 days before an election, which means Jan. 2 for the presidential primary, Simon said.

"We would hope this issue would be resolved so we don't have to delay the start of absentee voting," Simon said. Absentee voting for the primary starts Jan. 19.

In their article, Baude and Paulsen pointed to the 14th Amendment's third section, which they say disqualifies Trump from office with no need for Congressional action. "It can and should be enforced by every official, state or federal, who judges qualifications," they wrote.

Section Three supersedes other constitutional rules, including the First Amendment, and covers a broad range of conduct, including indirect participation or providing aid or comfort to insurrectionists, they wrote.

"It disqualifies former President Donald Trump, and potentially many others, because of their participation in the attempted overthrow of the 2020 presidential election," the paper states.

Section Three was created in 1866 and remains in place even though it was added during Reconstruction. "Section Three was prompted by historical circumstances, but that does not in any way detract from its enduring force," the law professors wrote.

The section is blunt. "It is insistent. It seems to have been deliberately designed to turn the prior Southern political order upside down," they wrote.

Baude and Paulsen said the section was reflective of its era. "It was more important to strip insurrectionists and rebels of governing power completely, to remake Southern political society thoroughly, and to prevent Southern backsliding from the full consequences of Union victory entirely, than to be concerned about such things as seeming harshness, impracticality, or disruptiveness," the article read.

The legal theory also has the endorsement of former Fourth U.S. Circuit Court of Appeals Judge J. Michael Luttig, a renowned conservative jurist, and Laurence Tribe, professor emeritus of constitutional law at Harvard University.

Luttig and Tribe, writing in the Atlantic, said Trump need not be convicted to be disqualified from the ballot. "The former president's efforts to overturn the 2020 presidential election, and the resulting attack on the U.S. Capitol, place him squarely within the ambit of the disqualification clause, and he is therefore ineligible to serve as president ever again."