A multi-pronged effort to keep Donald Trump off the 2024 presidential ballot as an insurrectionist resumes in earnest, beginning with a court case in Colorado on Monday, the first of two states that will hear legal arguments this week. Those seeking to have the former president ruled ineligible are relying on a civil war-era provision of the 14th amendment to the US constitution that states no person can hold public office if they “have engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof”. They argue that Trump’s incitement of the deadly 6 January attack on the US Capitol, in which his supporters attempted to block Congress certifying Joe Biden’s 2020 election victory, perfectly encapsulates the clause that has yet to be seriously tested in a courtroom. In Denver on Monday, and in Minnesota’s supreme court on Thursday, hearings are being held in cases that could ultimately end up in the US supreme court, regardless of which side wins in the lower court. The rulings are likely to be swiftly appealed, dragging the cases out with next year’s general election only 12 months away. “We’ve had hearings with presidential candidates debating their eligibility before – Barack Obama, Ted Cruz, John McCain,” said Derek Muller, a law professor at the University of Notre Dame, listing candidates challenged on whether they met the constitutional requirement of being a “natural-born citizen”. But the arguments against Trump, he said, rely on an obscure clause of the constitution with an “incendiary” bar against insurrection. “Those legal questions are very heavy ones,” he said, noting that even if they are seen as long shots, they raise important issues and have a plausible legal path to success. Among those who support the argument for Trump’s removal from the ballot are the Virginia senator Tim Kaine, Hillary Clinton’s 2016 running mate, who told ABC last month that the “language is specific” in the 14th amendment clause. “In my view, the attack on the Capitol that day was designed for a particular purpose at a particular moment and that was to disrupt the peaceful transfer of power as is laid out in the constitution,” he said. “So I think there is a powerful argument to be made.” In court in Denver on Monday, Eric Olson, an attorney for a group of Colorado voters recounted Trump’s violent rhetoric preceding the January 6 attack and his encouraging a crowd that came within “40 ft” of then vice-president Mike Pence when they stormed the Capitol. He said Trump “summoned and organized the mob”. “We are here because Trump claims, after all that, that he has the right to be president again,” Olson said. “But our constitution, the shared charter of our nation, says he cannot do so.” Trump’s legal team and 2024 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. Before the trial on the lawsuit began, his lawyers filed a motion to have the judge recuse herself because she had donated in the past to a liberal group in the state. She said no. The campaign also noted the current lawsuit was filed by a liberal nonprofit in a state that voted for Democrat Joe Biden in 2020. “They send money to these dark money groups, they go to a Democratic jurisdiction and a Democratic judge,” the Trump spokesman Jason Miller said. The trial is unfolding in stages, starting with a description of the attack and Trump’s words and actions, followed by arguments over whether the assault actually constituted an insurrection. Later in the week, lawyers are expected to call constitutional experts to delve into the meaning of the amendment’s insurrection clause. Trump’s lawyers contend the former president never “engaged in insurrection” and was simply exercising his free speech rights to warn about election results he did not believe were legitimate. Dozens of cases citing the amendment have been filed in recent months, but the ones in Colorado and Minnesota seem the most important, according to legal experts. They were filed by two liberal groups with significant resources, and in states with a clear, swift process for challenges to candidates’ ballot qualifications. That means the Colorado and Minnesota cases are taking a more legally sound route to get courts to force election officials to disqualify Trump, in contrast to other lawsuits that seek a sweeping ruling from federal judges that Trump is no longer eligible for the presidency. The Citizens for Responsibility and Ethics in Washington (Crew) watchdog group filed the Colorado lawsuit. “By instigating this unprecedented assault on the American constitutional order, Trump violated his oath and disqualified himself under the 14th Amendment from holding public office, including the office of the president,” its filing states. Trump’s lawyers say the provision has not been used in 150 years, and the plaintiffs are interpreting it incorrectly.