Chapter 04 / Open vs closed
Open vs closed primary: what changes for voters
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What is the difference between an open and closed primary?
An open primary lets any registered voter take part regardless of party, while a closed primary lets only enrolled party members vote.
That one rule decides whether independents get a ballot. There are 15 closed-primary states in 2026, where 66,284,669 registered Americans cannot vote in primary elections they help pay for. Open primaries remove that barrier entirely.
Open and closed primaries, defined
Open primary: any registered voter may vote, usually by choosing one party’s ballot in private, without enrolling in a party. Closed primary: only voters enrolled in a party may vote in its primary, so independents receive no primary ballot. Between them sit semi-open and semi-closed systems.
Open vs closed primary, side by side
| Question | Open primary | Closed primary |
|---|---|---|
| Who can vote? | Every registered voter | Enrolled party members only |
| Can independents vote? | Yes | No |
| Must you join a party? | No | Yes, often weeks or months ahead |
| Crossover voting? | Possible, 3 to 20 percent | Blocked |
| Number of states, 2026 | 19 open, plus 3 nonpartisan | 15 |
Pros and cons of open primaries
Pros
- Every voter, including the 63 million registered independents, can vote in the round that often decides the race.
- Candidates have reason to appeal beyond their most loyal party voters.
- Tax-funded elections are open to all taxpayers, not only party members.
Cons
- Crossover voting, 3 to 20 percent in open primaries, lets outsiders influence a party’s pick.
- Parties lose some control over who represents them on the ballot.
- Traditional open primaries still make voters choose one party’s contest.
Nonpartisan top-two primaries answer the last two points by dropping separate party contests. See which states have top-two primaries.
Why do parties prefer closed primaries to open primaries?
Parties prefer closed primaries because they keep the choice of nominee in members’ hands, limit crossover voting, and protect the party’s platform. Courts have recognized a party’s right to keep non-members out.
The counterargument is that the same Constitution protects a voter’s right not to join, and that primaries are run and paid for by the state. That argument is now in federal court in Rieckhoff v. Berger, filed October 1, 2026, over New York’s closed primaries, which bar 3,187,610 registered voters, 25.4 percent of the electorate.
The closed-primary states in 2026
Connecticut, Delaware, Florida, Iowa, Kansas, Kentucky, Louisiana, Maryland, Nevada, New Jersey, New York, Oregon, Pennsylvania, South Dakota, Wyoming.
In New York, a voter must enroll in a party by February 14 to vote in that year’s June primary.
If you are independent in a closed state
- Look up your state’s enrollment deadline with your state election office.
- Decide whether to enroll in a party for this cycle or stay unaffiliated.
- Back the national open primaries for every voter campaign, or take action here.
- Compare all six systems in the best primary systems 2026 rankings.
Methodology
Comparisons are based on who may vote, whether party enrollment is required, and exposure to crossover voting. Every entry is judged on the same criteria using published state election rules and the named sources on this page. We did not run our own surveys or polls. Read how we rank primary systems for the full approach.
Common questions
- What is the difference between open and closed primaries?
- The difference is who gets a ballot. In an open primary, any registered voter can participate regardless of party. In a closed primary, only registered party members can vote in that party’s contest, so independents sit out. In New York alone, 3,187,610 registered voters are barred from closed primaries.See this answer in the full FAQ
- What are the pros of open primaries?
- The main advantage of open primaries is that every voter can take part in the round that often decides the race. They include independents, who make up 28.9 percent of registered voters nationally. Supporters argue they reward candidates who appeal beyond a party base, and they stop tax-funded elections from being limited to party members.See this answer in the full FAQ
- What are the cons of open primaries?
- The most cited downside of open primaries is crossover voting, where voters from one party try to influence another party’s nominee. Crossover voting in open primaries is 3 to 20 percent. Parties also argue that members, not outsiders, should choose nominees, a position courts have often protected.See this answer in the full FAQ
- Why do parties prefer closed primaries to open primaries?
- Parties prefer closed primaries because they keep control of who chooses the nominee. Only loyal members vote, which limits crossover voting and protects the party’s platform and leadership. Critics answer that primaries are publicly funded elections, so excluding taxpaying voters who decline to join a party is unfair.See this answer in the full FAQ
- Can I vote in a primary if I am registered with a party in a closed state?
- Yes, in a closed-primary state you can vote in your own party’s primary, but not another party’s. Changing parties takes planning: in New York, a voter must affiliate by February 14 to vote in that year’s June primary. Check your state election office for its exact deadline.See this answer in the full FAQ
- What happens to independents in New York primaries?
- Independents in New York cannot vote in primaries at all, because New York runs closed primaries. That excludes 3,187,610 registered voters, 25.4 percent of the electorate. On October 1, 2026, the case Rieckhoff v. Berger was filed in federal court in the Southern District of New York challenging that exclusion.See this answer in the full FAQ
Your next step
Start with open primaries. Then explore More Choice Voting.
Getting every voter a primary ballot is the first barrier to clear. The Independent Voter Project runs the national campaign for open primaries for every voter, and our More Choice Voting chapter covers what comes after.