Open Primary

• An open primary is a primary voting system in which a voter, regardless of party affiliation, can pick the ballot of any party he chooses to vote for in that particular primary. For instance, a Democratic voter could vote in a Republican primary in a state with an open primary.
  
  

Closed Primary

• A closed primary is a primary election in which you can only vote for the party of which you are a declared member. Closed primaries often exclude independents from being able to vote because primaries generally are only needed to decide the nominations of the Republican and Democratic parties.
  
  

California's Proposition 14

• In 2010, voters in California are scheduled to decide on Proposition 14, a proposal that would give California an open primary system that allows voters to choose candidates of any party affiliation with no regard to the voter's party affiliation. The general election would have the two candidates with most votes go against each other, regardless of party. Some have criticized the proposal because it may result in many Democrat vs. Democrat races and make the cost of running a campaign much higher. Washington state is already using a similar system to the one proposed for California.
  
  

States With Open Primaries

• According to the website FairVote, the following states have open primaries: Alabama, Arkansas, Georgia, Idaho, Indiana, Michigan, Minnesota, Mississippi, Missouri, North Dakota, South Carolina, Tennessee, Texas, Vermont, Virginia, Washington and Wisconsin.
  
  

States with Closed Primaries

• According to the website FairVote, the following states have closed primaries: Alaska, Arizona, Colorado, Connecticut, Delaware, Florida, Hawaii, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Nebraska, Nevada, New Mexico, New York, North Carolina, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Dakota, Utah and Wyoming. Primaries in the District of Columbia also are closed.
  
  

States With Ambiguous Rules

• Some states currently have laws that do not really fall into the open or closed primary category. For instance, in California, Democrats allow independents to vote in their primaries, whereas Republicans have a closed primary. In Illinois, voters can change party affiliation at the polls. In Massachusetts, New Hampshire and New Jersey, independent voters are given a choice of what party's ballot to vote on, while registered voters have to stick with their party. In Montana and West Virginia, the Republican vote is closed, but the Democratic one is open. In Ohio, you have to vote in the same primary as you did last election, but it is apparently only loosely enforced.