It’s a ranked choice primary.

Resolves YES to the candidate if a candidate receives 50.00%+ in the first round.

Resolution criteria

The Maine Democratic Senate primary is scheduled for June 9, 2026, and will be conducted with ranked-choice voting. The market resolves YES if any candidate receives 50.00%+ of first-round votes. The ranked-choice system comes into play if none of the candidates capture more than 50% support on the first vote tally on Election Day. Results will be verified through the Maine Secretary of State Elections website.

Background

Graham Platner, a Sullivan Harbor Master, announced his candidacy in August 2025 with support from organized labor and Vermont Senator Bernie Sanders, along with progressive Democratic senators. Governor Janet Mills announced she will enter the race to defeat Republican U.S. Senator Susan Collins. Mills is the tenth Democrat to announce plans to seek her party's nomination. Other candidates include former U.S. Agency for International Development official David Costello and cybersecurity professional Tucker Favreau.

Considerations

The primary will be a ranked-choice election if at least three of the candidates remain on the ballot, with the ranked-choice system coming into play only if no candidate captures more than 50% on the first vote tally. A candidate winning 50%+ in the first round would avoid the ranked-choice tabulation process entirely.