The state’s highest court is moving quickly on a case that will determine whether Maine voters make history in November by using ranked-choice voting in the presidential election.

The Maine Supreme Judicial Court will hear oral arguments Thursday on a case that pits the Maine Republican Party against Secretary of State Matt Dunlap, a Democrat, who is appealing a lower court ruling. The high court will have until Sept. 24 to make a ruling.

At stake is whether a people’s veto initiative asking Maine voters if they want to use ranked choice in presidential primary and general elections will appear on the November ballot.

The clock is also ticking for Dunlap, who needs to prepare statewide ballots in time for printing and distribution to absentee voters, who are expected to participate in record numbers to reduce their risk of contracting COVID-19.

Attorneys for Dunlap and the Maine Republican Party filed their respective responses with the high court Monday.

If the court allows the question to appear on the ballot, ranked choice would would not be used for the race between President Trump, Democratic nominee Joe Biden and three other candidates.

If the high court rules in favor of Dunlap, the veto question would not appear on the November ballot and voters would be allowed to rank their choices for president.

Maine, one of only two states to split its Electoral College votes by congressional district, awards one vote to the winner of each of its two districts and two votes for the statewide winner. In 2016, Maine split its electoral votes for the first time since 1988 when the 2nd Congressional District voted for Trump by a 10-point margin, but Democrat Hillary Clinton won the 1st District and the statewide race.

This year, five candidates appear on the ballot, including Trump, Biden, the Green Party’s Howard Hawkins, the Libertarian Party’s Jo Jorgensen and the Alliance Party’s Rocky De La Fuente. That could spell trouble for Trump if he isn’t preferred over Biden by voters whose top pick is a third-party candidate.

Maine’s ranked-choice system has now twice been endorsed by voters statewide but has been rejected by 2nd District voters. Maine uses ranked choice in legislative and gubernatorial primaries as well as congressional primary and general elections.

The system will also be used for the first time in a U.S. Senate race in November. Incumbent Republican Sen. Susan Collins is running against Maine House Speaker Sara Gideon, a Democrat, Green Party candidate Lisa Savage and independent Max Linn.

The system allows, but doesn’t require, voters to rank candidates in descending preference. If no candidate wins more than 50 percent of the vote in the first round of tabulation the candidate with the fewest votes is eliminated, and their voters’ second choices are reallocated to the remaining field. This continues until one candidate has more than 50 percent of the votes.

The system has withstood repeated challenges in federal court. Most recently, a federal judge in Bangor again rejected a legal challenge by the Republican Party to its use in the U.S. Senate race in Maine and the party chose not to appeal.

Last week, the Maine Republican Party got its first legal victory when a Cumberland County Superior Court justice overturned Dunlap’s determination that the people’s veto effort did not collect enough valid voter signatures to place it on the ballot. Just under 1,000 signatures had been rejected because they were collected by circulators who were not registered to vote when they were collecting signatures, which is required under the Maine Constitution.

Leaning heavily on a prior U.S. Supreme Court decision, Cumberland County Superior Court Justice Thomas McKeon ruled that Maine’s constitution was in conflict with the U.S. Constitution and that the requirement that circulators be registered voters violated the circulators’ 1st Amendment rights.

But Dunlap’s office pointed to a state Supreme Judicial Court precedent that had rejected a similar appeal based on the same federal case McKeon had cited.

Dunlap’s appeal, filed by Assistant Attorney General Phyllis Gardiner, noted that a federal court had found in 1999 that Maine’s requirement that circulators be registered voters was not in conflict with the U.S. Constitution. Gardiner also notes that the Maine Republican Party did not argue or show it had any difficulty in finding registered voters to serve as petition circulators.

“They successfully engaged a total of 543 circulators, only 10 of whom were found to be unregistered at the time they collected signatures,” she wrote.

Gardiner also noted McKeon made a factual error in not rejecting signatures that were duplicates or signatures of people who were not registered to vote. Even if the high court agrees that the petitions from unregistered circulators were allowed to stand, the people’s veto backers would still be 22 signatures short of the number needed to put the question on the ballot.

But in his response, Patrick Strawbridge, the attorney for the Maine Republicans, argued that court rules allowing for an automatic stay of a superior court justice’s decision while a case is being appealed do not apply in this case.

Strawbridge, who has also served as Trump’s attorney in cases before the U.S. Supreme Court, also contended that both the Committee for Ranked Choice Voting and Dunlap are now attempting to introduce new evidence that was not in question during McKeon’s deliberations.

He also argues that allowing the veto question to move forward does not cause any harm, and that keeping the question off the ballot this close to the election would likely add to voter confusion.

“Their claim for irreparable harm is weak, given that the Superior Court’s order at most simply maintains the longstanding status quo for Presidential elections in Maine,” Strawbridge wrote. “And the competing harms are great, given that a stay would deny the Appellees the ability to exercise their fundamental right to place the veto before the people of this state within the timeline mandated by the Maine Constitution.”

Dunlap’s appeal asks the Law Court to stay the lower court decision and allow his decision to stand, leaving the people’s veto question off the ballot in November. The court is likely to act earlier than Sept. 24 given that the ballot needs to printed in time to be sent to absentee voters by Oct. 3.

The case is the second ballot question to be resolved by the Law Court this year. In mid August the court found a ballot question seeking to stop a Central Maine Power transmission line expansion was unconstitutional, striking it from the fall ballot.