How Maine’s Primary Election System Works

Maine uses a semi-open primary system, meaning voters who are registered with a political party may vote only in that party’s primary election. However, unenrolled (independent) voters may choose either a Democratic or Republican ballot when participating in a primary.

Voters who are already enrolled in a political party must vote in that party’s primary unless they change their registration before the applicable deadline. Maine’s primaries are used to select each party’s nominees for offices such as U.S. Senate, U.S. House, governor, statewide offices, and state and local positions.

Maine does not hold traditional primary runoff elections. Instead, the state uses Ranked-Choice Voting (RCV) for federal primary elections. If no candidate receives a majority of first-choice votes, the candidate with the fewest votes is eliminated and their votes are redistributed based on voters’ next choices until a candidate earns a majority.