Back in November, residents of Maine voted for a better way to vote—and now they may never enjoy the privilege. In a unanimous decision, the Maine Supreme Court ruled on Tuesday that the state’s ranked-choice voting system, chosen by voters at the ballot box in November, violates the state’s constitution.

Maine voters were the first in the nation to adopt the reform, in which voters rank candidates from 1 to 5, for elections for state and federal office. Also known as “instant runoff” voting, the system makes third-party candidates more viable by eliminating the spoiler effect. Voters who picked the candidate with the fewest first-place votes have their votes instantly reallocated until one candidate has a majority.

Thanks to the popularity of independent candidates and the state’s plurality system, no Maine governor has been elected by a majority in nearly 20 years.

Back in November, I wrote that the referendum was a rare victory for centrist candidates and independents, and a blow to party politics. Ranked-choice voting is popular around the world and has been used in some American cities. But Maine’s approval seemed to be a watershed moment.

Not anymore. The problem, the court said, is that the state constitution stipulates candidates should be elected “by a plurality of all votes.” “According to the terms of the Constitution, a candidate who receives a plurality of the votes would be declared the winner in that election,” the justices wrote. “The Act, in contrast, would not declare the plurality candidate the winner of the election, but would require continued tabulation until a majority is achieved or all votes are exhausted.”

Those plurality requirements date from the mid-19th century, after a spate of elections in which no candidates managed a majority, prompting repeat elections (for representatives), outcomes decided by sitting legislators (for senator and governor), general displeasure, and the threat of violence. In other words, the language was devised to avoid mandating majorities, but its broader aim was to restore voting choice to voters.

Supporters of Maine’s new system, which was supposed to take effect for elections next year, argued that ranked-choice voting does not consist of multiple rounds, but factors in all rankings at once. There is no sense in ascertaining a “plurality” until all votes have been allocated between two candidates, at which point plurality and majority are synonymous.

The path forward is difficult: Amending Maine’s constitution requires a two-thirds approval in both chambers of the statehouse, and another plebiscite. Maine State Sen. Cathy Green, a Democrat, said on Tuesday she will propose the referendum as a constitutional amendment.

The state’s Republicans have generally been opposed to the change, the Bangor Daily News writes, but they may be under pressure now to draft a constitutional change to comply with voters’ wishes.