When Scott Gessler stepped up to the lectern in a Denver courtroom on Monday, he opened with a full-throated defense of American democracy. “When it comes to decide who should lead our nation, it’s the people of the United States of America who should make those decisions,” he said. “This court should not interfere with that fundamental value – that rule of democracy.” It wasn’t so much the argument that was significant as much as who Gessler was representing: Donald Trump. The same Donald Trump who fought doggedly to have courts, state legislators, his vice-president and members of Congress throw out valid electoral slates from several states and declare him the winner of the 2020 presidential election. Gessler is defending the former president in a novel case in Colorado seeking to block him from appearing on the state’s ballot – a case that centers around whether Trump is disqualified from running for president under section 3 of the 14th amendment. The Reconstruction-era provision disqualifies anyone from holding office if they have taken an oath to the United States and subsequently “engaged in insurrection or rebellion against the same” unless Congress votes to remove that disqualification by two-thirds vote. It is not the only one of its kind: the Minnesota supreme court heard a similar case this week and there is also a similar case already pending in Michigan, a key battleground state. States are tasked with ensuring that candidates for office meet the qualifications so the challenges to Trump’s candidacy are bubbling up through state court. The 14th amendment cases are part of a mosaic of legal efforts that seek to hold Trump and his allies accountable for overturning the 2020 election, but they are among the most important. While the cases are dry – steeped in legalese and historical understanding of constitutional text – they get at Trump in a way that none of the other suits can: blocking his return to political life. While the other cases could require Trump and his allies to face jail time, lose their law licenses, and pay damages for defamatory lies, none of them would block Trump from returning to the White House in 2024 (a criminal conviction does not disqualify someone from running or serving as president). If he wins the election, he could theoretically pardon himself in the federal cases against him or dismiss the prosecutions. And while no pardon would be available in the Georgia criminal case, it’s untested whether the constitution would allow a state to incarcerate a serving, elected president. Simply put, winning the election is widely seen as Trump’s best chance at escaping the criminal charges against him. Losing the 14th amendment cases would cut off that possibility. “Let me be clear. The purpose of our actions is to obtain rulings that Trump is disqualified from the ballot, not merely to have a political debate. Not at all to have a political debate. Not merely to air issues,” said Ron Fein, the legal director for Free Speech for People, a left-leaning group that filed the challenge in Minnesota. “The dangers of Trump ever being allowed back into public office are exactly those foreseen by the framers of section 3. Which is that they knew that if an oath-taking insurrectionist were allowed back into power they would do the same if not worse.” The 14th amendment measure was passed after the civil war and has never been used to block a presidential candidate from the ballot. It picked up steam this summer after a pair of conservative scholars authored a law review article saying that it applied to Trump. Trump’s lawyers have defended him by arguing that his conduct on January 6 did not amount to an insurrection, that Congress needs to pass a law to enforce the 14th amendment, and that its language does not apply to the president. But expert witnesses for the challengers in the Colorado case offered a wealth of historical and other evidence this week suggesting that what Trump did on January 6 was an insurrection as the framers of the 14th amendment would have understood it. Legal observers almost universally agree that the US supreme court, where Trump appointed three of the six members of the court’s conservative super-majority, will ultimately decide the issue and whether Trump is eligible to run for re-election. There is not a clear legal consensus and since the law is so untested, it’s not clear what the court will do. Outside of the courtroom, the biggest challenge may be getting a wide swath of Americans to accept the idea that someone they support may not be eligible to run for president. In a democracy, there is something viscerally distasteful about not being able to vote for the person we support, Ned Foley, a law professor at the Ohio State University, noted earlier this year. It’s a question the supreme court justices in Minnesota seemed to be wrestling with as well, acknowledging the case was coming up on a line between politics and the law. “Let’s say we agree with you that section 3 is self-executing, and that we do have the authority under the relevant statute to keep Mr Trump’s name off the ballot. Should we – is the question that concerns me the most,” Natalie Hudson, the chief justice of Minnesota’s supreme court said on Thursday during oral argument. But the challengers in the cases, which are supported by left-leaning groups, argue that disqualifying Trump based on the 14th amendment is no different than disqualifying someone because they are under the age of 35, a naturalized citizen, or because they have served two terms as president. “In many ways, section 3 sets forth a qualification for president that is far more important than the other constitutional criteria,” Fein said. “Most Americans are not too worried about whatever dangers might have once been posed by somebody who was not a natural born US citizen. “But someone who broke an oath to the constitution and then engaged in insurrection or rebellion against the constitution poses a real danger if they’re ever allowed back into power.”