HALLOWELL — A trio of Democrats running for Maine governor stood side by side Wednesday to accept an unusual three-way endorsement during a press conference along the Kennebec River.

The candidates — Hannah Pingree, Troy Jackson and Shenna Bellows — took turns praising each other while also making the case for why they should be elected over the other two.

Bellows talked about their shared values. Jackson called the other two “great friends and great colleagues.” And Pingree congratulated Jackson on his soon-to-be-born grandchild after complimenting her opponents on their work on climate and the environment.

It was a friendly scene made possible in large part by the use of ranked-choice-voting in the upcoming primaries on June 9, where Maine’s unique elections system is certain to factor into the outcome.

While no candidates have officially formed alliances, Wednesday’s event was a sign that they are maneuvering for second, or even third, choice votes.

“Of course, each of us wants to be ranked No. 1, but if we’re not somebody’s No. 1, we want to be their No. 2,” Bellows said to reporters. “I think ranked-choice voting creates partnerships on important issues, and we have a lot of mutual respect for each other.”

Maine, along with Alaska, is one of just two states that use ranked-choice voting at the statewide level, though it is also in place in some municipalities nationwide.

Experts say the system will be crucial in deciding this year’s Maine governor primaries, which feature five Democrats and seven Republicans. Both parties have crowded races where it is almost certain that no single candidate will secure more than 50% of the vote in the first round.

“In elections with many candidates, it’s quite possible that the eventual nominee is not the candidate who leads in first-choice votes, but rather the one who is broadly acceptable and able to accumulate second- and third-choice support as ballots are redistributed,” said Rob Glover, an associate professor of political science at the University of Maine.

Because of that, he said that ranked-choice voting can factor heavily into campaign strategies. Candidates not only have an incentive to mobilize a strong base, but also to appeal to voters who may initially prefer someone else.

WHAT IS RANKED-CHOICE VOTING?

Ranked-choice voting, approved for statewide use by Maine voters in 2016, allows voters to rank candidates in order of preference in races featuring three or more contenders.

If no candidate gets more than 50% support in the first round, then the last-place finisher is eliminated, the second-choice votes of that candidate’s supporters are reallocated to the remaining candidates, and the results are retabulated. The process repeats until a winning candidate receives more than 50% support.

In this year’s governor’s race, polling has shown that support is widely spread out among the contenders.

A Pan Atlantic Research poll released last month found Nirav Shah and Angus King III tied with 24% likely support each among Democratic primary voters, followed by Pingree with 18%. On the Republican side, Bobby Charles led with 26% support among likely voters, followed by Garrett Mason with 11%.

Proponents of the system have long argued that ranked-choice voting is more fair because it ensures the candidate with the broadest support wins and eliminates the “spoiler effect” of a third candidate drawing votes away from a more viable option. They also say it makes for more civil campaigning, since candidates know that they may end up needing their opponents’ supporters to get to the winning threshold.

Opponents say it’s confusing and can unfairly lead to the person with the most first-choice votes losing — as was the case for former U.S. Rep. Bruce Poliquin, R- 2nd District, who lost re-election to U.S. Rep. Jared Golden in the nation’s first use of ranked-choice to determine a congressional election in 2018.

Poliquin led Golden by more than 2,900 votes after Election Day, but neither received majority support during the initial tally, with both pulling in roughly 46%. Two independents received a combined 8 percent of the vote. After the ranked-choice run-off, Golden emerged victorious with 50.5% of the vote to Poliquin’s 49.5%.

Poliquin challenged the outcome in court, but lost. He conceded the race to Golden, but said at the time that he continued to believe the voting method is unconstitutional and illegal — arguments that have since been repeated by other Maine Republicans.

DOES IT MAKE CAMPAIGNING MORE CIVIL?

Democrats, who generally have been supportive of ranked-choice voting, said at Wednesday’s event there is truth to the civility claims from proponents. Their Republican counterparts don’t necessarily agree.

The Republican primary has had some more contentious moments so far, such as when real estate developer David Jones used his entire closing statement at a March debate to criticize Charles.

Joel Stetkis, Charles’ campaign chair, said in an email that opponents’ attacks have become “increasingly slanted and misleading” after some received unfavorable internal polling.

“While proponents of ranked-choice voting argue it improves civility, recent weeks have shown that not to be true,” Stetkis said Wednesday.

Republicans don’t appear to be forming any alliances, but that could change.

The Democratic primary for U.S. Senate has also seen plenty of attacks thrown between Gov. Janet Mills and political newcomer Graham Platner, with Mills recently taking heat for a series of negative ads highlighting past controversial comments by Platner on social media.

Although polling says Platner is up big, there’s a small chance that race could also be determined by ranked-choice since it features a third candidate, David Costello — though Costello lags Mills and Platner significantly in polling and fundraising. (And Costello’s supporters don’t have to put Mills or Platner second; they could opt to leave those slots blank.)

But civility was certainly on display at the Wednesday event, where the Sierra Club of Maine endorsed three of the five Democrats vying to replace Mills, who is termed out. Emma Conrad, chair of the club’s political committee, said they have not previously endorsed three candidates at once.

“But given that it’s a ranked-choice primary and these candidates have a combined decades of experience being environmental champions in Maine, we’re encouraging our members to rank them as their top three,” she said.

The club said in a press release that it is not picking a top candidate. The “endorsement is an equal endorsement of all three candidates,” it said.

Pingree, Bellows and Jackson — who might otherwise be engaging in attacks in an effort to win over voters — said their public show of camaraderie may also be due to their pre-existing relationships from having all spent years working in Augusta.

“We’ve had long relationships, and we don’t want to destroy those relationships because of a campaign,” Pingree said. “The three of us know each other the best. We’ve known each other the longest (of the candidates in the race) and so that’s why this endorsement means a lot.”

At the state level, ranked-choice voting is currently used only in primaries and federal elections — both primaries and general — in Maine. A proposed expansion for use in the general election for governor and legislative seats was abandoned by lawmakers earlier this spring.

The Maine Supreme Judicial Court advised that the expansion would violate the Maine Constitution’s requirements for winners in those races to be determined by a plurality, or whoever receives the most votes.

Jackson lamented that the expansion didn’t go through, but said he is happy to see ranked-choice voting used in the primary.

“It is a lot nicer to be able to work with each other than be fighting,” he said.