WASHINGTON — The US Supreme Court has struck down efforts by individual states to disqualify Donald Trump from running for president using an anti-insurrection constitutional clause.

The unanimous ruling is specific to Colorado, but it also overrides challenges brought in other states.

Colorado had barred Trump from its Republican primary, arguing he incited the 2021 Capitol riot.

The court ruled that only Congress, rather than the states, has that power.

The top court's decision clears the way for Trump to compete in the Colorado primary scheduled for Tuesday.

The ex-president immediately claimed victory following the ruling, taking to his Truth Social media platform to claim a "big win for America".

The message was quickly followed by a fundraising email sent to supporters of his campaign.

"Today's decision, especially the fact that it was unanimous, 9-0, is both unifying and inspirational for the people of the United States," Trump told Fox News in an interview on Monday morning.

Colorado's Secretary of State, Jena Griswold, said that she was disappointed by the ruling and that "Colorado should be able to bar oath-breaking insurrections from our ballot."

Additionally, the watchdog group that brought the case in Colorado, Citizens for Responsibility and Ethics in Washington (Crew), said in a statement that while the court "failed to meet the moment", it is "still a win for democracy: Trump will go down in history as an insurrectionist".

Two other states, Maine and Illinois, had followed Colorado in kicking Trump off the ballot on similar grounds.

The efforts in both states were put on hold while his challenge to the Colorado ruling was escalated to the Supreme Court.

"We conclude that states may disqualify persons holding or attempting to hold state office," the court's opinion says. "But states have no power under the Constitution to enforce Sections 3 with respect to federal offices, especially the presidency."

The nine justices ruled that only Congress can enforce the 14th Amendment's provisions against federal officials and candidates.

Part of the Civil War-era amendment — section 3 — bars federal, state and military officials who have "engaged in insurrection or rebellion" against the US from holding office again.

Groups including Free Speech For People had argued that the attempt to delay the peaceful transfer of power on Jan. 6, 2021 matched the definition of insurrection outlined in the amendment.

One of the court's justices, Amy Coney Barrett, wrote separately that the fact that all nine justices agreed on the outcome of the case is "the message that Americans should take home".

"The court has settled a politically charged issue in the volatile season of a presidential election," Barrett wrote. "Particularly in this circumstance, writings on the court should turn the national temperature down, not up."

But the court's three liberal justices argued that the ruling seeks to "decide novel constitutional questions to insulate this Court and [Trump] from future controversy" by announcing "that a disqualification for insurrection can occur only when Congress enacts a particular kind of legislation".

"In doing so, the majority shuts the door on other potential means of enforcement," they added.

Trump is the front-runner for the Republican nomination and looks likely to face a rematch with Democratic President Joe Biden in November's general election.

Republican voters in Colorado and 14 other states will vote on Tuesday in a marathon contest dubbed Super Tuesday.

The former president is widely expected to sweep the board and defeat his sole remaining opponent, former UN Ambassador Nikki Haley, in every battleground.

One political professor said the Supreme Court's ruling avoids having to answer questions about Trump's involvement in the 2021 US Capitol riot.

Inderjeet Parmar, international politics professor at City University of London saids "what the Supreme Court has done in effect is sidestepped the question of the insurrection".

He added that the Court has also "argued that states have no right to adjudicate on whether or not someone can stand for Federal office, they can adjudicate only, or probably can adjudicate only on those who can stand for State offices".

"So in effect the Supreme Court has pushed over to the US Congress the means by which anybody may be adjudged to have violated that article 3 of the 14th Amendment of the Constitution."

Allies of Trump took to social media to show their support after the Supreme Court ruling.

Republican senator JD Vance, who was elected off the back of Trump's endorsement, describes it as a "great ruling for our country and the rule of law".

"In America the people decide who the president is," he said.

Representative Byron Donalds, from the hard-right flank of the Republican party, said the Supreme Court has "chosen the side of freedom".

"Colorado's ruling was an unprecedented display of rank political partisanship at the hands of unelected officials," he said.

Republican congresswoman Marjorie Taylor Greene says: "Trump stays on the ballot in communist states committing election interference by trying to block Americans from being able to vote for the candidate of their choice!" — BBC