Maine Has Semi-Open Primary Elections. What Does That Mean for You?

Since 2022, independent voters in Maine have had the ability to participate in a political party’s primary election for congressional and state offices.

Voters who have formalized their political affiliation are only permitted to cast a ballot selecting candidates for their own political party.

Maine is one of ten states to make use of this kind of primary system, alongside Arizona, Colorado, Iowa, Kansas, Massachusetts, New Hampshire, Rhode Island, West Virginia, and Wyoming.

After receiving bipartisan approval in both the House and Senate, the bill establishing open primaries went into law without a signature from Gov. Janet Mills (D) in May of 2022.

Fifteen states still have closed primaries, wherein voters can only participate in a primary election if they are a registered member of that party. Unenrolled voters are not eligible to participate in primary elections.

Twenty states employ an even less restrictive form of open primary that allows all voters to choose which party’s primary they would like to participate in when they show up at the polls. Voters in these states are not required to formally designate themselves as affiliated or unaffiliated with a political party.

California, Washington, and for some elections in Nebraska, there are no party primaries. Instead, all candidates vying for a given seat compete against one another in a single primary election. The two candidates with the most votes move on to the general election.

Alaska has a very similar system, except that the top four candidates advance to the general election.

Louisiana utilizes a run-off system in which there are no primary elections. All eligible candidates appear on the November ballot. If no candidate receives more than 50 percent of the vote, the top two candidates move on to a run-off election held in December.

So what does Maine’s use of a semi-open primary mean in practice for voters looking to participate in Tuesday’s election?

Anyone who is registered as a Democrat or Republican will be given the appropriate ballots to select candidates for their party.

Mainers who are unenrolled, however, will be asked which party’s ballot they’d like to fill out.

Unenrolled voters cannot mix and match ballots for different races. Just as in a closed primary, voters are only allowed to weigh in on candidates for a single party.