Open Primary States 2025

State	Primary Type	Congressional/State	Presidential	System
Alabama	Open w/ NR	Open	Open	All voters must choose one party's ballot to vote on, but they are not tied to that party. But voters who do not participate in either primary will only be given the amendments/referendum ballot.
Alaska	Closed	Open (Top-Four)	Closed	Voters may vote for one candidate per race without consideration for political affiliation. This includes nonpartisan and undeclared.
Arizona	Closed	Open to Unaffiliated	Closed	While party members may only vote on that ballot, unaffiliated voters may choose which ballot to vote on.
Arkansas	Open w/ NR	Open	Open	Each voter will be able to choose which ballot they vote on, but they will be held to that party in the case of a run-off. Unaffiliated voters that decide not to participate in either party's primary will receive the amendments/referendum ballot only.
California	Closed	Top-Two	Closed	As of 2022, California is attempting a Top-Two system, where all registered voters receive one ballot regardless of party affiliation, and the top two move on to the general election.
Colorado	Open w/ PR	Open	Open	Colorado voters don't have to declare a party but must choose one party's ballot.
Connecticut	Closed	Closed	Closed	Connecticut voters must declare a party in advance to vote in that party's primary.
Delaware	Closed	Closed	Closed	Delaware voters must declare a party in advance to vote in that party's primary.
Florida	Closed	Closed	Closed	Florida voters must declare a party in advance to vote in that party's primary.
Georgia	Open w/ NR	Open	Open	Georgia voters don't have to declare a party but must choose one party's ballot.
Hawaii	Closed	Open	Closed	Hawaii voters don't have to declare a party but must choose one party's ballot.
Idaho	Closed	Closed	Closed	Voters must be a member of a party to participate in the primary. Parties may or may not open primaries to unaffiliated voters.
Illinois	Open w/ NR	Open	Open	Illinois voters do not have to register with a party, but they do have to choose one party's ballot to vote publically. The choice is legally considered a public declaration and can be challenged by other voters.
Indiana	Open w/ NR	Open	Open	While affiliation with a party is not required to vote in the primary, Indiana has laws of intent that impact your vote in the general election.
Iowa	Open w/ PR	Open	Open	Iowa voters must be registered with a party to vote in the primary.
Kansas	Open w/ PR	Open	Open	While registered voters can participate in their party's primary, unaffiliated voters can declare their party the day of and vote on that ballot.
Kentucky	Closed	Closed	Closed	Kentucky party-affiliated voters can only vote in that party's primary.
Louisiana	Closed	N/A	Closed	Louisiana holds no primaries. They list all candidates on a single ballot, and all registered voters may participate.
Maine	Closed	Semi Open	Closed	In 2024, Maine voters can cast ballots in one party's primary without having to join that party.
Maryland	Closed	Closed	Closed	Six months before the primary, each party has to notify the State Board of Elections if they are opening or closing their primary as state laws permit them to choose.
Massachusetts	Open w/ PR	Open	Open	Six months before the primary, each party has to notify the State Board of Elections if they are opening or closing their primary as state laws permit them to choose.
Michigan	Open w/ NR	Open	Open	Michigan voters do not declare affiliation but must choose a party's ballot to vote on.
Minnesota	Open w/ NR	Open	Open	Minnesota voters do not declare affiliation but must choose a party's ballot to vote on.
Mississippi	Open w/ NR	Open	Open	Mississippi voters do not declare affiliation, but they do have to choose a party's ballot to vote.
Missouri	Open w/ NR	Open	Open	Missouri voters do not declare affiliation, but they do have to choose a party's ballot to vote.
Montana	Open w/ NR	Open	Open	Montana voters do not declare affiliation, but they do have to choose a party's ballot to vote.
Nebraska	Closed	Closed	Closed	Voters may or may not choose to affiliate with a political party. However, affiliation with a party is required to vote in certain primary elections.
Nevada	Closed	Closed	Closed	Nevada voters must be registered in a party to participate in the primary.
New Hampshire	Open w/ PR	Open	Open	New Hampshire voters must be affiliated to participate in a party's primary, while unaffiliated voters may choose one party's ballot to vote on. But that action makes them a member of the chosen ballot's party.
New Jersey	Closed	Closed	Closed	Voters must be a member of a party to participate in the primary.
New Mexico	Closed	Closed	Closed	New Mexican voters must be registered with a party in order to vote in a primary.
New York	Closed	Closed	Closed	Voters in New York must be a member of a party to participate in the primary.
North Carolina	Open w/ NR	Open	Open	While voters aren't required to declare a party, they are required to choose one party's ballot to vote on.
North Dakota	Closed	Open	Closed	All candidates are listed on one ballot, which means party affiliation is not necessary to participate in the primary. Voters can only choose candidates from one party. (If they vote for more than one party, the ballot will be rejected.)
Ohio	Open w/ NR	Open	Open	Each voter in Ohio chooses one party's ballot to vote on, and that choice determines their political affiliation.
Oklahoma	Closed	Closed	Closed	Voters must be registered with a party to participate in their primary. In Oklahoma, Independent voters are allowed to participate in Democratic primaries, but not Republican.
Oregon	Closed	Closed	Closed	Oregon voters must be registered with a party to participate in the primary.
Pennsylvania	Closed	Closed	Closed	Pennsylvania voters must be registered with a party to participate in the primary.
Rhode Island	Open w/ PR	Open	Open	All unaffiliated voters choose one party's ballot to cast their vote in the primary. This choice is viewed as a party declaration.
South Carolina	Open w/ NR	Open	Open	South Carolina voters do not declare affiliation, but they do have to choose a party's ballot to vote.
South Dakota	Closed	Closed	Closed	Voters must be registered with a party to participate in their primary. In South Dakota, unaffiliated voters can participate in Democratic primaries without changing their status. This does not apply to Republican primaries.
Tennessee	Open w/ NR	Open	Open	Tennessee voters do not declare affiliation, but they do have to choose a party's ballot to vote.
Texas	Open w/ NR	Open	Open	Texas voters do not declare affiliation, but they do have to choose a party's ballot to vote.
Utah	Closed	Closed	Closed	Voters must be registered with a party to participate in their primary. In Utah, unaffiliated voters can participate in Democratic primaries without changing their status. This does not apply to Republican primaries.
Vermont	Open w/ NR	Open	Open	Vermont voters do not declare affiliation, but they do have to choose a party's ballot to vote.
Virginia	Open w/ NR	Open	Open	Virginia voters do not declare affiliation, but they do have to choose a party's ballot to vote.
Washington	Closed	Open	Closed	Each voter receives the same primary ballot, using a top-two system, regardless of affiliation. The presidential primary, on the other hand, is closed.
West Virginia	Open w/ PR	Open	Open	In West Virginia, parties decide who may participate in their primaries. As of 2022, both major parties allow unaffiliated voters to participate in their primaries. But party members must vote in their own primary.
Wisconsin	Open w/ NR	Open	Open	Wisconsin voters do not ahev to declare affiliation, but they do have to choose a party's ballot to vote. This choice does not change their affiliation.
Wyoming	Open w/ PR	Open	Open	Wyoming's voters must register with a party to vote in that party's primary, while unaffiliated voters may register with a party at the polls to vote in that party's primary.

Voting in America varies from state to state as each holds different laws for factors such as registration and which voters may participate in primaries. Moreover, these rules often differ for congressional/state and presidential primaries.

Open, Open, and Closed: The Three Types of Primary Elections

Primaries fall into one of three categories with regard to voter eligiblity: Closed, Open Partisan, and Open Nonpartisan.

Closed Primary

Only voters who are officially registered with a party may vote in that party’s primary election. Also, their own party’s primary election is the only one in which a voter may vote (Ex: Only voters registered as Republicans may vote in the Republican primary, and they may not vote in the Democratic primary).

Open Primary with Partisan Registration

Voters who are already registered with a party may vote in that party’s primary election—and only that party’s election (same as a closed primary). However, independent voters who are not registered with any party may also vote in any party’s primary, though they may only vote in one party’s primary each election cycle (Ex: A voter not registered with either party may vote in the Republican or Democratic primary, but not both).

Open Primary with Nonpartisan Registration

All voters may vote in any party primary regardless of their registration status, but may still only vote in one primary per election cycle. For example, a voter registered as a Republican may forego the Republican Primary and instead vote in the Democratic (or Libertarian, or any other party) primary if they prefer, but they could not then also vote in the Republican primary.

States with Open Primaries

As mentioned, these rules are up to each state and, in some cases, are up to each party. When looking to vote in your state, be sure to do your research. Some states have made amendments in 2022 to make voting more or less open.

For example, New Mexico has begun to allow unaffiliated voters to participate in primary votes by allowing them to show up to the polls and change their registration status.

Top-Two Primaries

Washington and California have what is known as a top-two primary. This type of primary election lists all candidates on the same primary ballot and the top two candidates, regardless of their partisan affiliation, advance to the general election.

California has a modified closed primary between 2001 and 2011, which allowed each political party to decide whether they would permit unaffiliated voters to vote in their primary.

This system eased the constitutional concerns of both the open and closed primary systems. The Republican, Democratic, and American Independent parties all chose to permit unaffiliated voters to request their party’s ballot in the 2004 and 2006 primaries, but the Republican Party has not opted for this since the 2008 presidential election.

In 2011, California adopted a modified open primary, allowing individual citizens to vote for any candidate, and the top two candidates, regardless of party, advance to the general election. This method is a contest for state delegates and is not used for the Presidential election.

Support and Opposition of Open Primaries

Supporters of open primaries argue that open primaries could increase voter participation as there are fewer restraints on your options. Open primaries allow nonpartisan or independent voters to nominate presidential candidates, making them more likely to vote in the general election. Also, someone in the middle may agree more with a single candidate of one party and encourage them to vote in the open primary and general elections.

On the other hand, opponents of the open primary system argue that it is bad for voter participation since the closed primary system has more incentive for people to join one of the major parties.

Opponents also argue that the open primary could lead to dilution and manipulation if one party plans to have its voter vote in the other party’s primary. In this event, voters could choose the less desirable or the one that could be easily defeated by the first party.

Additionally, opponents argued that the open primary is unconstitutional because it violates their freedom of association. This is because open primaries allow outsiders of their party to select their candidates. To counter this argument, supporters argue that the U.S. Constitution does not mention political parties.