Maine Attorney General Janet T. Mills says a citizen initiative that would establish ranked-choice voting must go to voters, but the bill raises “significant constitutional concerns” and may be impossible to implement without amending the Maine Constitution.

Mills’ opinion came in response to a request from Senate President Michael Thibodeau, R-Winterport, for a legal opinion on whether a citizen-initiated referendum proposal to establish a ranked-choice voting system in Maine violates the Maine Constitution. A citizen-initiated referendum to establish ranked-choice voting for state and federal elective offices will be on the November ballot unless it is first ratified by the Legislature.

The Committee for Ranked Choice Voting, a state organization that gathered the signatures to put the question to voters, insists that the system it seeks to implement in Maine conforms to the state constitution.

Mills, in a letter to Thibodeau dated March 4, said the citizen-initiated bill, L.D. 1557, must be presented to voters unless the Legislature enacts it without change this session. She said the citizen initiative must go to voters even if it presents constitutional issues.

Thibodeau’s request for a legal opinion came after a Portland Press Herald report in which a top state election official said that ranked-choice voting is at odds with a provision in the Maine Constitution that says winners of gubernatorial and State House races are determined by a plurality of votes cast. Ranked-choice voting would swap the traditional plurality system with one that determines a winner after he or she secures a majority of votes cast.

Mills said the proposal does raise “significant constitutional concerns” and it “may not be possible to implement ranked-choice voting as envisioned by this legislation without amending the Maine Constitution.”

Dick Woodbury, a former state senator who serves as chairman of the Committee for Ranked Choice Voting, on Saturday praised Mills’ conclusion that lawmakers cannot stop the citizen initiative from going to voters and reiterated that backers of the initiative believe it meets Maine’s constitutional requirements.

“This reform is incredibly important to the future of Maine politics,” he said in a statement. “It restores majority rule and puts power back in the hands of voters, so politicians are more accountable to the people. It’s a real solution that we can adopt now to help break gridlock and polarization in government.”

Mills said the state constitution provides for winners to be determined by “a plurality of all votes returned” and for votes to be counted by local election officials in each municipality.

“It does not contemplate multiple rounds of tallying (and redistributing) voters’ preferences through a centralized, computer-driven process administered by the Secretary of State until a majority winner can be determined,” she wrote.

Mills said ranked-choice voting is “a fundamentally different process” that cannot be performed at the local level. She said nothing in the constitutional provisions authorizes the secretary of state to process ballots or to count votes on individual ballots, a function that is currently carried out by municipal officials.

Mills also raised concern about how the bill would handle a tie in a gubernatorial election. The bill provides that a tie between candidates in the final round of the ranked-choice voting process would be decided by lot, which Mills says is in direct conflict with Article V of the Maine Constitution. The constitution says that, in the event of a tie vote, the House and Senate meet in joint session to cast votes and elect a governor.

If voters support the question and any constitutional barriers are cleared, Maine could become the first state to swap its traditional voting system for ranked choice.

Under ranked-choice voting, voters rank candidates in order of preference. If no candidate gets more than 50 percent of the votes cast after the first tally, the candidate with the fewest votes is eliminated. Voters who chose the eliminated candidate have their ballots added to the totals of their second-ranked candidate and the ballots are retabulated. This process continues until one candidate has a majority of votes and is declared the winner.