An appeals court in Colorado on Tuesday ruled that Donald Trump cannot appear on the state's presidential primary ballot because of his involvement in the attack on the Capitol in January 2021.

The ruling, which only applies to the Colorado primary ballot, is the first of several legal actions across the country, aimed at invoking the US Constitution's 14th Amendment, which bars from office anyone formerly sworn to protect the country who later engages in insurrection.

"A majority of the court holds that President Trump is disqualified from holding the office of President under Section Three of the Fourteenth Amendment to the United States Constitution," the Supreme Court of the State of Colorado wrote.

"Because he is disqualified, it would be a wrongful act under the Election Code for the Colorado Secretary of State to list him as a candidate on the presidential primary ballot."

The legal decision follows a challenge by a group of voters who contested a previous ruling. This ruling had determined that despite clear evidence of Trump's involvement in the January 6 riot, it would not disqualify him from running for the presidency again.

That ruling hinged on the interpretation of the 14th Amendment to the US Constitution that bars a person from holding "any office... under the United States" if they engaged in insurrection after taking an oath as "an officer of the United States" to support the Constitution.

But the amendment cannot apply to Trump, since the presidency is left out of the list of federal elected positions affected by the law, the lower court decided.

Noah Bookbinder, of the campaign group Citizens for Ethics, which brought the case, took to social media to hail Colorado's Supreme Court's ruling, dubbing it "a huge moment for democracy."

The court placed its ruling on hold, anticipating an appeal to the US Supreme Court, which Trump's campaign immediately said it would seek.

"We will swiftly file an appeal to the United States Supreme Court and a concurrent request for a stay of this deeply undemocratic decision," campaign spokesman Steven Cheung said in a statement.

Cheung said, "Democrat Party leaders are in a state of paranoia over the growing, dominant lead President Trump has amassed in the polls."

"They have lost faith in the failed Biden presidency and are now doing everything they can to stop the American voters from throwing them out of office next November," he added.

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