The state-by-state rules for voting in the primaries in the United States are extremely complex, as each state has derived its own unique way of approaching the nominating primary. Because of this, voters should treat the information below as a rough guideline, and they may want to check with the secretary of state in the state they plan to vote in to make sure that they are registered properly for primary elections. Election rules also change, sometimes dramatically, and this is very important to be aware of for people who are planning to vote.
Nominating elections in the United States are done in several ways. Some states have closed primaries, which means that you must be registered with a specific primary before voting in these locations. Others have open primaries, allowing voters to vote any ballot for any party. Many states have adopted a semi-closed system, which is sometimes called a semi-open system, in which voters may be able to request the ballots of specific political parties in the primaries. Not all parties allow non-partisan voters to request their ballots in a semi-closed primary, so if voting a particular party ballot is important to a voter, he or she may want to register with that party for the primary. Some states use conventions and caucuses, using meetings and gatherings to nominate candidates, and other states hold both caucuses and primaries, typically with the caucuses coming first.
States that hold traditional closed primaries include Connecticut, Delaware, Florida, Kentucky, Maryland, Nebraska, New Jersey, New Mexico, New York, North Carolina, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Dakota, Utah, and Washington DC. In West Virginia, Republican conventions are held early in the year of a presidential election, followed by a closed primary for all parties.
Seven states hold semi-closed primaries: Arizona, California, Massachusetts, New Hampshire, Ohio, Texas, and Illinois. Within these states, different parties have different rules about whom they allow to vote on their ballots, so voters should check with the registrar of voters in their area. In California, for example, non-partisan voters may vote on the Democratic ballot, but not the Republican ballot.
Open primaries are held in Alabama, Arkansas, Georgia, Idaho, Indiana, Michigan, Mississippi, Missouri, Tennessee, South Carolina, Vermont, Virginia, and Wisconsin. Montana holds a closed Republican caucus early in the year, followed by an open primary.
Colorado, Hawaii, Iowa, Kansas, Maine, and Nevada hold closed caucuses. Wyoming holds county and state conventions where voters are allowed to select candidates, while Minnesota and North Dakota hold open caucuses. In Alaska, the caucus is semi open. Washington holds an open caucus earlier in the year, followed by an open primary, while Louisiana has an open, nonpartisan primary system.