Former President Donald Trump on Wednesday asked the U.S. Supreme Court to overturn a ruling barring him from the Colorado ballot, setting up a high-stakes showdown over whether a constitutional provision prohibiting those who “engaged in insurrection” will end his political career.

Trump appealed a 4-3 ruling in December by the Colorado Supreme Court that marked the first time in history that Section 3 of the 14th Amendment was used to bar a presidential contender from the ballot. The court found that Trump’s role in the Jan. 6, 2021, attack on the U.S. Capitol disqualified him under the clause.

The provision has been used so sparingly in American history that the U.S. Supreme Court has never ruled on it. Wednesday’s development came a day after Trump’s legal team filed an appeal against a ruling by Maine’s Democratic Secretary of State, Shenna Bellows, that Trump was ineligible to appear on that state’s ballot over his role in the Capitol attack. Both the Colorado Supreme Court and the Maine secretary of state’s rulings are on hold until the appeals play out.

Trump’s critics have filed dozens of lawsuits seeking to disqualify him in multiple states. He lost Colorado by 13 percentage points in 2020 and does not need to win the state to gain either the Republican presidential nomination or the presidency. But the Colorado ruling has the potential to prompt courts or secretaries of state to remove him from the ballot in other, must-win states.

None had succeeded until a slim majority of Colorado’s seven justices — all appointed by Democratic governors — ruled last month against Trump. Critics warned that it was an overreach and that the court could not simply declare that the Jan. 6 attack was an “insurrection” without a judicial process.

“The Colorado Supreme Court decision would unconstitutionally disenfranchise millions of voters in Colorado and likely be used as a template to disenfranchise tens of millions of voters nationwide,” Trump’s lawyers wrote in their appeal to the nation’s highest court, noting that Maine has already followed Colorado’s lead.

Prominent activist and publisher Jimmy Lai on Tuesday pleaded not guilty to three charges of sedition and collusion with foreign countries in a landmark national security trial in Hong Kong.

Lai was arrested during a crackdown on dissidents following huge pro-democracy protests in 2019. He faces possible life imprisonment if convicted under a sweeping national security law imposed by Beijing. The trial is expected to last about 80 days without a jury.

The 76-year-old media tycoon who founded the now-defunct Apple Daily newspaper faces one count of conspiring to print seditious publications to incite hatred against the Chinese and Hong Kong governments, as well as two counts of collusion with foreign countries to call for sanctions and other hostile actions against China and Hong Kong.

Flanked by three prison officers, Lai formally pleaded not guilty to the charges read to him, shortly after the court rejected a last-ditch attempt by his counsel to throw out a sedition charge.

Prosecutor Anthony Chau in his opening statements described Lai as a “radical political figure” and the “mastermind” behind a conspiracy. Chau also said that Lai had used his media platform to advance his political agenda.

Clips of interviews that Lai gave to foreign media as well as speeches at events between 2019 and 2020 were also played in court. In the video, Lai called for support from foreign governments and urged U.S. officials as well as then-President Donald Trump to impose “draconian” measures on China and Chinese officials in retaliation for imposing the national security law and restricting freedoms in Hong Kong.

His prosecution has drawn criticism from the United States and the United Kingdom. Beijing has called those comments irresponsible, saying they went against international law and the basic norms of international relations.

The Inter-Parliamentary Alliance on China, or IPAC, an international political group that’s critical of China’s human rights record and foreign policy, said Lai’s trial “fabricated” evidence that the media mogul was involved in its work.