Maine’s state elections are decided by Ranked-Choice Voting (RCV), a run-off system in which voters rank the candidates in order of their preference. Voters still cast a vote for their favorite candidate, but on the ballot they also list their second, third, and fourth choice for the office. If no single candidate gets a majority (more than 50% of the votes), the state redistributes votes to the top two vote-getters based on the voter’s listed preferences.

In the initial election, Poliquin received 131,466 votes, giving him 46.2% of the vote. With no candidate receiving a majority, the votes cast for the last place candidates—independent party candidates Tiffany Bond and William Hoar—were redistributed to Poliquin and Golden, dependent on the voter’s rankings. After the process was complete, Maine’s Secretary of State named Golden the winner with 50.5% of the vote.

Maine, like most other US states, previously decided elections by plurality. Whichever candidate had the most votes was declared the winner. In Maine, a state with a strong history of independent political affiliation, that meant most candidates failed to reach a majority. Before Janet Mills’ victory in the gubernatorial election this year, no Maine governor had won a majority in their first term since 1966.

In 2016, activist groups led by the bipartisan Committee for Ranked Choice Voting succeeded in getting a popular referendum to install RCV in Maine state elections. It was not without controversy. The campaign ran into obstacles over concerns of its constitutionality at the state level. Janet Mills, the then-attorney general, wrote a letter in March 2016 suggesting that while the referendum was legal, RCV would have to be enshrined in the Maine constitution in order to take effect. Governor Paul LePage forcefully opposed the measure, later calling it “the most horrific thing in the world,” and threatened that he would not certify the results of any election held by RCV.

Despite the concerns, voters approved the measure by a 52-48 margin. Maine’s state legislature still had concerns over the measure’s compatibility with the state constitution, and Maine Republicans feared they would be at an electoral disadvantage if the measure was implemented. They delayed RCV until 2021, in effect telling the Committee for Ranked Choice Voting to pass the motion as a popular amendment to the state constitution, rather than a popular ballot initiative. Voters balked. Supporters of RCV initiated a people’s veto, whereby Maine voters can hold a popular election to directly veto an act of the state congress. That vote, held in June of 2018, passed by over 20,000 votes, ensuring RCV would be used for the 2018 midterms.

The legal battles over RCV may not be over. On November 13, 2018, Poliquin filed a lawsuit against the Maine Secretary of State to halt the voting count, claiming that RCV violated the 1st and 14th amendments of the US Constitution. Federal Judge Lance E. Walker denied Poliquin’s request, though the incumbent vows to fight on.

“It is now officially clear I won the constitutional ‘one-person, one-vote’ first-choice election on Election Day that has been used in Maine for more than 100 years,” he said. “We will proceed with our constitutional concerns about the rank-vote algorithm.”

Poliquin and other opponents of RCV should not get their hopes up for a victory in the courts. As Judge Walker himself pointed out, Maine voters have already approved RCV twice, and judges are historically averse to reversing the results of elections.

With Poliquin’s lawsuit looking like a long-shot, Golden will likely be sworn into Congress in the new year. His victory provides another important win for Democrats; every congressional seat from New England is currently occupied by a member of the Democratic Party. Indeed, the only Republican member of Congress from New England is Senator Susan Collins, whose seat is a key target for Democrats in 2020.

Perhaps by then, the constitutionality of ranked-choice voting in Maine will finally be settled.