FILE - ME Janet Mills 6-26-2019

Maine Gov. Janet Mills speaks during a news conference June 26, 2019.

A free market policy group is encouraging Maine Gov. Janet Mills to veto legislation passed this week that would all the state's voters to rank their presidential candidate preferences at the polls next year.

The Maine Heritage Policy Center on Thursday published a letter it sent to Mills asking her to veto the legislation.

"In the average ranked-choice voting election, 11 percent of ballots are thrown out due to ballot exhaustion," the policy center said in its letter. "This causes the average winner of these elections to win with a fake majority of the votes cast on Election Day approximately 61 percent of the time."

The ranked-voting measure passed at the end of Monday’s special session, after Democratic Senate President Troy Jackson renewed it for a vote, which was 20-12, mainly along party lines.

The bill, LD1083, now goes to Mills, who won the gubernatorial primary in June 2018 on a ranked-vote ballot – the first time it had been used by any state in the country for statewide office.

David Farmer of the Committee for Ranked Choice Voting, a group that has led the ongoing campaign for the state’s use of the process, lauded Jackson’s decision to bring it up at the end of the special session. Given the number of candidates expected on the Democratic presidential primary ticket next spring, the committee was particularly pleased to see support for it from Maine legislators.

In an interview with the Portland Press Herald, Jackson, D-Allagash, said it was crucial to get the bill addressed or there would not be enough time to enact it before the March primary.

 But the Maine Heritage Policy Center said ranked-voting disenfranchises certain voters.

"Most troubling, our research found that the information costs of ranked-choice voting disenfranchise minority voters and voters with less education, the same individuals who are already less likely to participate in our elections," its letter said.

Constituents can use ranked voting when there are three or more candidates on the ballot. Should a candidate receive more than 50 percent of the vote on the first count, then that person is declared the winner. If no candidate receives a majority, then the candidate who has the fewest votes is removed and their votes reallocated.

That procedure is followed until one candidate secures a majority of the vote.