One of this November's closest and highest-profile U.S. Senate races could turn on a unique way of voting in Maine.
There, Republican incumbent Susan Collins is defending her seat against Democratic state House Speaker Sara Gideon as well as two independents. Polls show a close contest between Collins, who's seeking her fifth term, and the well-funded Gideon.
And Maine voters will use the ranked-choice voting system, which allows them to rank their choices among the four Senate candidates.
To someone not familiar with the process, it sounds complex. But Cara McCormick, co-founder of the Committee for Ranked Choice Voting, says it is something with which most of us are familiar.
"We rank choices in our everyday life all the time," she says. "We're always saying, you know, 'If they don't have the mint chocolate chip ice cream, can you please get me the rocky road?' " In terms of voting, "It allows people to really express their full range of opinions and preferences about all of the candidates running. And it's definitely working for us in Maine. And I think it's definitely encouraging more positive campaigns."
The ballot voters will use is pretty straightforward, says Kathleen Montejo, city clerk in Lewiston, Maine.
"Once folks look at it, it does seem to be fairly intuitive, and you fill in the little bubble," she says. "It's almost like taking the SAT test, you know, from years ago. And you just fill in the little bubbles."
Montejo says once voters see it, their reaction is, "'Oh, this isn't as bad as I was expecting. This seems to be pretty straightforward and pretty simple.' "
The ranked-choice voting system was first used in the state's 2018 federal elections, so Maine voters are becoming more comfortable and familiar with the process.
But Montejo says many still have questions. "The No. 1 question we always get from folks is, 'Do I have to rank every candidate? Or if I just rank my No. 1 first choice and do not rank the other candidates, will my vote still count?' And the answer is yes."
Ranked-choice voting only comes into play if no candidate receives a majority — that is, 50% plus one vote. That happened in 2018 in Maine's 2nd Congressional District. Republican incumbent Bruce Poliquin received a plurality but not a majority, and after voters' second choices were counted, Democrat Jared Golden won the seat.
In this year's U.S. Senate race, one candidate, independent Lisa Savage, has used ranked-choice voting in her messaging, telling voters to make her their first choice and the Democrat Gideon their second one.
University of Maine political science professor Mark Brewer says that's problematic for Collins.
"In a ranked-choice voting scheme, assuming that Savage's supporters list Gideon second, which Savage is asking them to do, this now turns into a disadvantage for Collins," he says.
But it's unclear how the votes for the two independent candidates will break, with recent polls showing each with roughly the same share of the vote.
In a statement, the Collins campaign says "there is one clear choice" and it is encouraging voters to choose the incumbent as their first choice.
Republicans in the state continue to challenge ranked-choice voting in court, because it also applies to the presidential race.
Maine gives an electoral vote to the winners of each of the state's two congressional districts. And while polls show Democrat Joe Biden with a lead in the state overall, in the rural 2nd district it's a much closer race, says Anna Kellar, executive director of the League of Women Voters of Maine.
"The race between Biden and [President] Trump in that district is neck and neck," she says. "So if neither gets a majority, the votes cast for a third party or independent candidate may end up playing a role. But instead of being spoilers, those candidates, the second choices will end up probably deciding the vote."
So Maine's ranked-choice voting system could possibly have an effect not only on the makeup of the U.S. Senate — but even, conceivably, who wins the presidency.