PORTLAND, Maine — Maine’s Democratic secretary of state on Thursday removed former President Donald Trump from the state’s presidential primary ballot under the Constitution’s insurrection clause, becoming the first election official to take action unilaterally as the U.S. Supreme Court is poised to decide whether Trump remains eligible to return to the White House.

The decision by Secretary of State Shenna Bellows follows a ruling earlier this month by the Colorado Supreme Court that booted Trump from the ballot there under Section 3 of the 14th Amendment. That decision has been stayed until the U.S. Supreme Court decides whether Trump is barred by the Civil War-era provision, which prohibits those who “engaged in insurrection” from holding office.

The Trump campaign said it would appeal Bellows' decision to Maine's state courts, and Bellows suspended her ruling until that court system rules on the case. In the end, it is likely that the nation's highest court will have the final say on whether Trump appears on the ballot in Maine and in the other states.

Bellows found that Trump could no longer run for his prior job because his role in the Jan. 6, 2021, attack on the U.S. Capitol violated Section 3, which bans from office those who “engaged in insurrection.” Bellows made the ruling after some state residents, including a bipartisan group of former lawmakers, challenged Trump’s position on the ballot.

“I do not reach this conclusion lightly,” Bellows wrote in her 34-page decision. “I am mindful that no Secretary of State has ever deprived a presidential candidate of ballot access based on Section 3 of the Fourteenth Amendment. I am also mindful, however, that no presidential candidate has ever before engaged in insurrection.”

The Trump campaign immediately slammed the ruling. “We are witnessing, in real-time, the attempted theft of an election and the disenfranchisement of the American voter,” campaign spokesman Steven Cheung said in a statement.

Legal experts said that Thursday's ruling demonstrates the need for the nation's highest court, which has never ruled on Section 3, to clarify what states can do.

“It is clear that these decisions are going to keep popping up, and inconsistent decisions reached (like the many states keeping Trump on the ballot over challenges) until there is final and decisive guidance from the U.S. Supreme Court,” Rick Hasen, a law professor at the University of California-Los Angeles, wrote in response to the Maine decision. “It seems a certainty that SCOTUS will have to address the merits sooner or later.”

While Maine has just four electoral votes, it’s one of two states to split them. Trump won one of Maine’s electors in 2020, so having him off the ballot there, should he emerge as the Republican general election candidate, could have outsized implications in a race that is expected to be narrowly decided.

That's in contrast to Colorado, which Trump lost by 13 percentage points in 2020 and where he wasn't expected to compete in November if he wins the Republican presidential nomination.

In her decision, Bellows acknowledged that the U.S. Supreme Court will probably have the final word but said it was important she did her official duty.

That won her praise from the former state lawmakers who filed one of the petitions forcing her to consider the case.

“Secretary Bellows showed great courage in her ruling, and we look forward to helping her defend her judicious and correct decision in court. No elected official is above the law or our constitution, and today’s ruling reaffirms this most important of American principles,” Republican Kimberly Rosen, independent Thomas Saviello and Democrat Ethan Strimling said in a statement.

But other Republicans in the state were outraged.

“This is a sham decision that mimics Third World dictatorships," Maine's House Republican leader, Billy Bob Faulkingham, said in a statement. “It will not stand legal scrutiny. People have a right to choose their leaders devoid of mindless decisions by partisan hacks.”

The Trump campaign on Tuesday requested that Bellows disqualify herself from the case because she'd previously tweeted that Jan. 6 was an "insurrection” and bemoaned that Trump was acquitted in his impeachment trial in the U.S. Senate after the capitol attack. She refused to step aside.

“My decision was based exclusively on the record presented to me at the hearing and was in no way influenced by my political affiliation or personal views about the events of Jan. 6, 2021,” Bellows told the Associated Press Thursday night.

Bellows is a former head of the Maine chapter of the American Civil Liberties Union. All seven of the justices of the Colorado Supreme Court, which split 4-3 on whether to become the first court in history to declare a presidential candidate ineligible under Section 3, were appointed by Democrats. Two Washington, D.C.-based liberal groups have launched the most serious prior challenges to Trump, in Colorado and a handful of other states.

That's led Trump to contend the dozens of lawsuits nationwide seeking to remove him from the ballot under Section 3 are a Democratic plot to end his campaign. But some of the most prominent advocates have been conservative legal theorists who argue that the text of the Constitution makes the former president ineligible to run again, just as if he failed to clear the document's age threshold — 35 years old — for the office.

Likewise, until Bellows' decision, every top state election official, whether Democrat or Republican, had rejected requests to bar Trump from the ballot, saying they didn't have the power to remove him unless ordered to do so by a court.

The timing on the U.S. Supreme Court's decision is unclear, but both sides want it fast. Colorado's Republican Party appealed the Colorado high court decision on Wednesday, urging an expedited schedule, and Trump is also expected to file an appeal within the week. The petitioners in the Colorado case on Thursday urged the nation's highest court to adopt an even faster schedule so it could rule before March 5, known as Super Tuesday, when 16 states, including Colorado and Maine, are scheduled to vote in the Republican presidential nominating process.

The high court needs to formally accept the case first, but legal experts consider that a certainty. The Section 3 cases seem tailor-made for the Supreme Court, addressing an area of U.S. governance where there's scant judicial guidance.

The clause was added in 1868 to keep defeated Confederates from returning to their former positions of power in local and federal government. It prohibits anyone who broke an oath to “support” the Constitution from holding office. The provision was used to bar a wide range of ex-Confederates from positions ranging from local sheriff to Congress, but fell into disuse after an 1872 congressional amnesty for most former Confederates.

Legal historians believe the only time the provision was used in the 20th Century was in 1919, when it was cited to deny a House seat to a socialist who had opposed U.S. involvement in World War I. But since the Jan. 6 attack, it has been revived.

Last year, it was cited by a court to remove a rural New Mexico County Commissioner who had entered the Capitol on Jan. 6. One liberal group tried to remove Republican Reps. Madison Cawthorn and Marjorie Taylor Greene from the 2022 ballot under the provision, but Cawthorn lost his primary so his case was thrown out, and a judge ruled for Greene.

Some critics of the movement to bar Trump warn that the provision could be weaponized in unexpected ways.

They note that conservatives could argue, for example, that Vice President Kamala Harris is likewise barred from office because she raised bail funds for people arrested during the unrest following George Floyd's 2020 murder at the hands of Minneapolis police.

The plaintiffs in Colorado presented historical evidence that even the donation of small sums to money to those seeking to join the Confederacy was grounds for being barred by Section 3. Why, critics have asked, wouldn't that apply to Democrats like Harris today?