Last Updated: 02/2008

Open primaries (or pick-a-party) are those in which voters of any affiliation may vote for the slate of any party.

Closed primaries are those in which only the voters affiliated with a party may vote in its primary.

Blanket primaries (or "jungle primaries") are those in which voters, regardless of affiliation, may choose the party primary in which they want to vote on an office-by-office basis. The blanket primary was struck down in 2001 by the Supreme Court in CA Democratic Party v. Jones.

The following is a running list of states by primary type: open, potentially closed, or with special provisions. We say "potentially" because these states require voters to affiliate by party, which allows parties the option to close their primaries.

Please contact [email protected]with any questions. Note: State and party rules change regularly and are often difficult to track with accuracy. Additionally, some of the definitions make it complicated to assign a state to one simple category. This list was compiled through phone calls to state election administrators. For more information on state primary regulations, please visit Ballot Access News.

State

Closed

Open

Other

Remarks

Alabama

x

Alaska

x

Closed caucuses for both parties, but voters may change party affiliation at polls or caucus.

Arizona

x

Arkansas

x

Open, but when runoff elections are used, voters must vote in same party's runoff election as they voted for in the first round election.

California

x

Parties may allow voters who decline to state their party affiliation to participate in their primaries. Democrats currently allow registered Democrats and independents to vote in their primary. Republicans currently have a closed primary.

Colorado

x

Connecticut

x

Delaware

x

District of Columbia

x

Only voters registered with the Democratic, Republican, D.C. Statehood Green or Umoja parties can vote in their party's primary.

Florida

x

Georgia

x

Open, but when runoff elections are used, voters must vote in same party's runoff election as they voted for in the first round election.

Hawaii

x

Idaho

x

x

Democrats have an open caucus in Idaho, while the Republicans have an open primary.

Illinois

x

Must vote in primary of same party as last primary the voter participated in. Loosely enforced.  Voters may change party affiliation at polls or caucus.

Indiana

x

Iowa

x

x

Closed caucuses, but voters may change registration at polls.

Kansas

x

x

In the Democratic caucus, independent voters can register as Democrat on caucus day. For Republicans it is a closed caucus.

Kentucky

x

Louisiana

x

x

Primaries are closed for presidential elections. For congressional elections, they are effectively open, because Louisiana currently uses a top-two runoff system ("cajun primary"). They will switch to a closed primary used for Congressional races after 2006.

Maine

x

Closed caucuses.

Maryland

x

Parties can choose to open primaries but both Democrats and Republicans have chosen not to.  If a voter does not choose a party, he or she will be recorded as “unaffiliated” and is permitted to vote in any nonpartisan primary in his or her local jurisdiction.

Massachusetts

x

Registered Democrats and Republicans can only vote for their own party in the primary but independent voters may decide which party they would like to vote for.

Michigan

x

Minnesota

x

Open caucuses.

Mississippi

x

Missouri

x

Montana

x

Republicans have a closed caucus, while Democrats have an open primary.

Nebraska

x

Nevada

x

Closed caucuses.

New Hampshire

x

Registered Democrats and Republicans can only vote for their own party in the primary but independent voters may decide which party they would like to vote for. Unregistered voters can register on election day.

New Jersey

x

Registered Democrats and Republicans can only vote for their own party in the primary. Any NJ voter who has never on a previous occasion voted in a NJ primary election may declare a party affiliation at the poll. Independents may also decide which party to vote for.

New Mexico

x

New York

x

North Carolina

x

If registered with a party, you must vote in that party's primary. If unaffiliated, you may choose a party on the day of the primary election.

North Dakota

x

North Dakota has no voter registration, you only have to prove that you have been a resident for at least 30 days.

Ohio

x

Must vote in primary of same party as the voter participated in last primary election. Loosely enforced.

Oklahoma

x

Oregon

x

Pennsylvania

x

Rhode Island

x

x

If you are registered as "unaffiliated" you may vote in the primary of any party you choose. Once you vote in a primary, however, you are considered a member of that party until and unless you "disaffiliate".

South Carolina

x

Open, but when runoff elections are used, voters must vote in same party's runoff election as they voted for in the first round election.

South Dakota

x

Tennessee

x

Texas

x

Open, but when runoff elections are used, voters must vote in same party's runoff election as they voted for in the first round election.

Utah

x

Currently only Republicans close their primary.  Democrats and independents can vote in the Democratic primary. Conventions are held by the political parties prior to the primary.

Vermont

x

Virginia

x

Parties may choose to nominate by convention rather than by primary election.

Washington

x

West Virginia

x

Republicans have a closed convention while Democrats will hold a primary where unaffiliated voters and independents may participate.

Wisconsin

x

Wyoming

x

Closed Caucuses.