The state is facing a federal lawsuit over ranked-choice voting – again.

Four Mainers have filed a complaint in U.S. District Court of Bangor to block the use of ranked-choice voting in the 2020 general election. They argue the system disenfranchises voters whose ballots are eliminated before the final round of tabulation, and they have asked the court to declare Maine’s law unconstitutional and prevent ranked-choice voting from being used in the November election.

“This case seeks to vindicate the constitutional rights of Mainers who will soon be denied full participation in the 2020 general election,” the complaint states.

Dozens of U.S. cities use ranked-choice voting, but Maine is the first state to have adopted the system. Maine voters have twice affirmed the law, supporting it on the ballot in 2016 and then overturning a legislative repeal in 2018. This year, opponents collected signatures for another referendum that would have stopped ranked-choice voting from being used in the November presidential election, but Maine Secretary of State Matt Dunlap rejected the petition last week.

The law previously withstood a federal legal challenge in 2018 after Democrat Jared Golden unseated Republican Bruce Poliquin in the 2nd Congressional District. Poliquin won the initial vote but did not have a clear majority. A federal judge later denied his request for a new election, and Poliquin ultimately dropped his legal challenge.

The system allows – but does not require – voters to rank candidates in order of preference. If one candidate gets more than 50 percent in the first round, that person wins. If no one receives a majority, the ranked preferences are used to decide the winner.

The candidate with the fewest first-choice votes is eliminated from the race. Then their supporters’ ballots are reallocated to their second-chance candidates for another tally. The process continues – with candidates being eliminated from the bottom up – until one person has received a clear majority.

The plaintiffs in the latest lawsuit are four Maine voters: Robert Hagopian of Madison, Duane Lander of Greenville, Sterling Robinson of Warren and James Trudel of Hermon. Three are registered Republicans; one is a registered independent.

They named three state officials as defendants: Dunlap, Attorney General Aaron Frey and Gov. Janet Mills.

They argued that people who did not completely fill out their ballots were disenfranchised in 2018 because those ballots were not counted in the final tally. They also said the ranked-choice voting system forces voters to rank candidates that they otherwise would not vote for in hopes of keeping their ballots in the final tally.

“If anything, the problem is likely to worsen this election,” the complaint states. “The ongoing COVID-19 pandemic all but guarantees that a much larger portion of voters will submit absentee ballots (than) in 2018. Without the ability to obtain in-person voting assistance, it is likely that even more Mainers will inadvertently miscast their ranked-choice ballots.”

The complaint specifically cited the four-way race for U.S. Senate in Maine. The candidates are incumbent Republican Sen. Susan Collins, Democratic Maine House Speaker Sara Gideon and independents Lisa Savage and Max Linn.

The state has not yet responded to the claims in the lawsuit. A spokeswoman for the Maine Secretary of State’s Office said she could not comment on pending litigation. Other spokespeople for the public officials named as defendants did not respond to an email about the complaint Thursday evening.

Supporters have argued that ranked-choice voting guarantees that candidates who are opposed by a majority of the Maine voters will not win because of split votes, and the process is easy for voters to use and understand.