Open to Unaffiliated Voters
A number of states allow only unaffiliated voters to participate in any party primary they choose, but do not allow voters who are registered with one party to vote in another party’s primary. This system differs from a true open primary because a Democrat cannot cross over and vote in a Republican party primary, or vice versa. New Hampshire requires that unaffiliated voters declare affiliation with a party at the polls in order to vote in that party’s primary. In Colorado, unaffiliated voters must return just one party’s mail ballot, or state which party ballot they want at the polls. The choice is public information, although it does not change the voter's unaffiliated status.
Open to Unaffiliated Voters Primary States
Arizona
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Colorado
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Kansas
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Maine
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Massachusetts
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New Hampshire
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Rhode Island
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Open Primaries
In general, but not always, states that do not ask voters to choose parties on the voter registration form are “open primary” states. In an open primary, voters may choose privately in which primary to vote. In other words, voters may choose which party’s ballot to vote, but this decision is private and does not register the voter with that party. This permits a voter to cast a vote across party lines for the primary election. Critics argue that the open primary dilutes the parties’ ability to nominate. Supporters say this system gives voters maximal flexibility—allowing them to cross party lines—and maintains their privacy.
Open Primary States
Alabama
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Arkansas
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Georgia
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Hawaii |
Michigan
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Minnesota
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Mississippi
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Missouri |
Montana
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North Dakota
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South Carolina
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Tennessee |
Texas
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Vermont
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Virginia
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Wisconsin |
Top-Two Primaries
California and Washington use a “top two” primary format. The “top-two” format uses a common ballot, listing all candidates on the same ballot. In California, each candidate lists his or her party affiliation, whereas in Washington, each candidate is authorized to list a party “preference.” The top two vote-getters in each race, regardless of party, advance to the general election. Advocates of the "top-two" format argue that it increases the likelihood of moderate candidates advancing to the general election ballot. Opponents maintain that it reduces voter choice by making it possible that two candidates of the same party face off in the general election. They also contend that it is tilted against minor parties who will face slim odds of earning one of only two spots on the general election ballot.
Other Primary Processes
State and federal elections in Louisiana, and legislative elections in Nebraska, share some common traits with top-two primaries, but are distinct.
In Louisiana, on the general election date, all candidates run on the same ticket. If no candidate receives over 50% of the vote, then the top two vote-getters face a runoff six weeks later. One way to look at this is to say there is no primary election--just a general election for all candidates, with a runoff when needed.
In Nebraska, legislators are elected on a nonpartisan basis. This means they run without a party designation, and all candidates are on the same nonpartisan primary ballot. (This system is common for local nonpartisan offices throughout the nation).
Alaska has a unique top-four open primary system for state and congressional offices.
Presidential Primary Rules
States may have radically different systems for how they conduct their state and presidential primaries: Some states hold their state and presidential primaries on the same day, some hold them weeks or even months apart, and some hold the two primaries on the same day but have different rules for each primary. See NCSL's State Primary Types Table for which state primary rules also apply to presidential elections.