The Colorado Republican Party is promising to switch to caucuses from primaries should the state supreme court’s ruling disqualifying President Trump from appearing on election ballots there be upheld.

Following the Colorado decision, California’s lieutenant governor, Eleni Kounalakis, is now asking the secretary of state there, Shirly Weber, to explore legal avenues for removing Mr. Trump from its 2024 ballot, according to a report from Politico.

“California is obligated to determine if Trump is ineligible for the California ballot for the same reasons described” in the Colorado supreme court ruling, Ms. Kounalakis wrote.

A group of voters who challenged Mr. Trump’s eligibility have also appealed a ruling this week allowing Mr. Trump to remain on ballots in Michigan, and has signaled that there are more suits to come.

In response to a statement from businessman Vivek Ramaswamy, in which the GOP presidential candidate promised to withdraw his name from the Colorado primary ballot should Mr. Trump’s name not appear on it, the Colorado GOP said it would switch to a caucus system if the ruling is upheld.

“You won’t have to because we will withdraw from the Primary as a Party and convert to a pure caucus system if this is allowed to stand,” the party said in a post on X, formerly known as Twitter.

Mr. Ramaswamy also called on other GOP hopefuls to withdraw their names, saying that not doing so means “they are tacitly endorsing this illegal maneuver which will have disastrous consequences for our country.”

Although none of the other GOP presidential candidates have said that they would withdraw their names from the Colorado ballots, they have rallied behind Mr. Trump.

“The Left invokes ‘democracy’ to justify its use of power, even if it means abusing judicial power to remove a candidate from the ballot based on spurious legal grounds. SCOTUS should reverse,” Governor DeSantis said.

A former ambassador to the United Nations, Nikki Haley, said, “I don’t think Donald Trump needs to be president,” but added, “I will beat him fair and square. We don’t need to have judges making these decisions, we need voters to make these decisions.”

Even Governor Christie, who has been one of Mr. Trump’s most vociferous critics in the Republican Party, said, “I do not believe Donald Trump should be prevented from being President of the United States by any court. I think he should be prevented from being the President of the United States by the voters of this country.”

The rest of the GOP is not far behind those running against Mr. Trump in voicing its support for the former president, with members of both the House and Senate attacking the Colorado court and announcing their support for Mr. Trump.

“Today’s ruling attempting to disqualify President Trump from the Colorado ballot is nothing but a thinly veiled partisan attack,” Speaker Johnson said. “Regardless of political affiliation, every citizen registered to vote should not be denied the right to support our former president and the individual who is the leader in every poll of the Republican primary.”

Senator Barrasso said that the ruling was “a blatant, political attempt to silence American voters. SCOTUS will rightly dispose of it in an ash heap.”

“This is the kind of wake-up call we should not ignore. Nor is this just another bad, politically motivated ruling,” Senator Lee said. “This is lawless thuggery masquerading as jurisprudence.”

Senator Tillis introduced a bill Tuesday that would punish states that disqualify Mr. Trump based on the 14th Amendment by withdrawing federal funds used for election administration in those states.

Some Republican state officials outside of Colorado, like the lieutenant governor of Texas, Dan Patrick, also have threatened retaliation against President Biden.

Mr. Patrick told Fox News that the Colorado ruling made him think that “maybe we should take Joe Biden off the ballot in Texas for allowing eight million people to cross the border since he’s been president, disrupting our state far more than anything anyone else has done in recent history.”

Democrats have been comparatively less vocal about the ruling in Colorado, though some of the top Democrats during Mr. Trump’s impeachments have weighed in.

“Trump’s disqualification in Colorado for insurrection was raised by GOP voters before the GOP primary, and the 14th Amendment came from the GOP,” Congressman Jamie Raskin said. “As Lincoln put it, insurrection is a war on the ‘first principle’ of democracy — our right to choose our own leaders.”

Congressman Ted Lieu said that he was pleased to see the Colorado court follow the Constitution and that “the Court appropriately held that Trump is disqualified” from being on the ballot.

While boarding Air Force One on Wednesday, Mr. Biden told reporters that he thinks that Mr. Trump “certainly supported an insurrection.”

“Whether the 14th Amendment applies, I’ll let the court make that decision,” Mr. Biden said. “He seems to be doubling down on everything.”