Maine will be the first state in the country to use ranked choice voting to choose a president, the state’s governor announced Friday.

Under the new system, voters will rank their choices for president in the general election instead of choosing just one (if there are more than two candidates on the ballot). If no candidate gets a majority of the vote, the candidate with the fewest first-place votes gets eliminated. The second choice votes of everyone who voted for the eliminated candidate then get distributed to those remaining. The process continues until a candidate gets a majority of the vote.

Advocates for the system, which is already used in some Maine elections and in other localities across the country, say it reduces partisanship and gives voters more power with their vote. Politicians have to go out and make their case to a wider swath of the electorate. Voters also get more power, advocates say, because they aren’t restricted to choosing just one candidate.

Maine lawmakers approved a bill allowing ranked choice voting in the presidential primaries and general elections in late August. Gov. Janet Mills (D) said Friday she would allow the bill to become law without her signature. Mills said she was making that decision in order to allow lawmakers to work out funding and technical details next year. But the delay also means that the law won’t go into effect until after the state’s March 3 presidential primary, when there are likely to be many candidates on the ballot. It will be in effect, however, for future presidential primaries in the state.

“My experience with ranked-choice voting is that it gives voters a greater voice and it encourages civility among campaigns and candidates at a time when such civility is sorely needed,” Mills said in a letter to the legislature. “At the same time, there are serious questions about the cost and logistics of ranked-choice voting, including collecting and transporting ballots from more than 400 towns in the middle of winter.”

Mills’ decision to let the measure become law was “historic,” said David Farmer, a spokesperson for the Committee for Ranked Choice Voting. Still, he said, it was disappointing the process wouldn’t be in effect for the 2020 primary.

“I think the Democratic primary right now where we have a large, diverse field of qualified candidates is a perfect example of why ranked choice voting is such an important reform,” he said. “With so many good candidates in there, voters can select their top choice without worrying about the spoiler effect or trying to calculate some triangle of electability.”

Maine allocates two of its four electoral votes to the winner of the statewide vote. Each of the remaining two get allocated to the candidate who gets the most votes in each of the state’s two congressional districts. The system means Maine election officials may have to complete multiple ranked choice tallies the night of the general election.