Primary Elections and Who Gets to Vote

What Is a Primary Election

A primary election is the vote that narrows the field before November. In most states, each party holds a primary to choose its nominee, and the winners face each other in the general election.

Primaries exist because parties used to pick candidates in closed-door conventions. Progressive-era reformers in the early 1900s pushed states to let voters choose instead, and today every state holds some form of primary. What separates one state’s primary from another is who gets to vote in it.

Why Primaries Decide Safe Districts

FairVote found that 367 of 435 House seats in 2024 were decided by 10 or more points. Only 37 were decided by fewer than 5 points. In those 367 districts, the general election confirmed what the primary had already decided.

Gerrymandering builds many of those safe districts. When district lines are drawn to guarantee one party wins, the only competitive election is the primary, and the dominant party’s nominee wins in November almost automatically. FairVote projected 81% of House seats as already safe for one party 18 months before the 2026 election.

Most House seats are settled in the primary, not in November.

How Many House Seats Were Competitive in 2024

Category	Value
Won by 10+ points or uncontested	367
Won by 5 to 10 points	31
Won by fewer than 5 points	37

Source: FairVote, 2024 House results. The middle bar is the remainder of 435 seats.

That leaves a small group of primary voters in a safe district with more say over its member of Congress than the much larger November electorate. Who is allowed into that small group depends on the state.

Six Types of Primary Elections

Every state sets its own primary rules, and the National Conference of State Legislatures sorts them into six types. The line that matters most for a voter is whether you must belong to a party before you can vote in its primary.

8

9

8

5

15

5

• Closed (8 states) Party members only. DE, FL, KY, NJ, NY, PA, TN, WY
• Partially closed (9 states) Each party decides whether unaffiliated voters get in. CT, ID, KS, MD, OK, OR, SD, UT, WV
• Open to unaffiliated (8 states) Unaffiliated voters pick one party; members cannot cross over. AZ, CO, MA, ME, NC, NH, NM, RI
• Partially open (5 states) Anyone can cross over, but the choice is public or counts as joining. IA, IL, IN, NV, OH
• Open (15 states) Any voter, private choice. AL, AR, GA, HI, MI, MN, MO, MS, MT, ND, SC, TX, VA, VT, WI
• Top-two, top-four, or other (5 states) One ballot for all candidates, or a mix. AK, CA, LA, NE, WA

Source: NCSL, State Primary Election Types, updated May 19, 2026. Louisiana and Nebraska use different systems for different offices.

The distinction matters most for the growing number of voters who register with no party. In a closed-primary state they are locked out of the election that decides most seats. Tennessee is the odd case: it has no party registration, so a voter joins a primary by declaring allegiance to the party at the polls.

Party-switch deadlines add a second barrier. In Kentucky you must change your registration by December 31 of the year before, about 139 days before the primary. In Connecticut, the deadline is the day before.

Why Closed Primaries Create a Representation Problem

Closed primaries in safe districts mean a small share of party-registered voters choose the representative for everyone. Independents, members of the other party, and anyone who missed the switch deadline have no meaningful vote in the contest that settles the seat.

Primary Rules and Deadlines in Your State

Find your state below. The deadline column is the last day a registered voter can switch parties (or join one) and still vote in that party’s primary.

Who can vote in your state's primary

Choose your state to see its primary type, whether unaffiliated voters can take part, and the deadline to switch parties.

Choose your state to see its rules Select a state AlabamaAlaskaArizonaArkansasCaliforniaColoradoConnecticutDelawareFloridaGeorgiaHawaiiIdahoIllinoisIndianaIowaKansasKentuckyLouisianaMaineMarylandMassachusettsMichiganMinnesotaMississippiMissouriMontanaNebraskaNevadaNew HampshireNew JerseyNew MexicoNew YorkNorth CarolinaNorth DakotaOhioOklahomaOregonPennsylvaniaRhode IslandSouth CarolinaSouth DakotaTennesseeTexasUtahVermontVirginiaWashingtonWest VirginiaWisconsinWyoming

Primary types from NCSL (updated May 19, 2026) and party-switch deadlines from NCSL (updated January 20, 2026), checked September 29, 2026. Louisiana from its Secretary of State. D.C. is not in NCSL's table. Party rules can change each cycle, so confirm with your state election office.

Who can vote in a party primary?

• Closed: party members only (8)
• Partially closed: each party decides (9)
• Open to unaffiliated voters (8)
• Partially open: choice is public (5)
• Open: any voter, private choice (15)
• Top-two, top-four, or other (5)

Sources: NCSL, State Primary Election Types (updated May 19, 2026); NCSL, Voter Party Affiliation Deadlines for Primaries (updated January 20, 2026); Louisiana Secretary of State, Closed Party Primary Elections. Verified September 29, 2026.

Who can vote in a party primary?

State	Who can vote in a party primary?
Alabama	Open
Alaska	Top-four (one ballot)
Arizona	Open to unaffiliated
Arkansas	Open
California	Top-two (one ballot)
Colorado	Open to unaffiliated
Connecticut	Partially closed
Delaware	Closed
Florida	Closed
Georgia	Open
Hawaii	Open
Idaho	Partially closed
Illinois	Partially open
Indiana	Partially open
Iowa	Partially open
Kansas	Partially closed
Kentucky	Closed
Louisiana	Party primaries for Congress and some state offices; one all-candidate primary for other state races
Maine	Open to unaffiliated
Maryland	Partially closed
Massachusetts	Open to unaffiliated
Michigan	Open
Minnesota	Open
Mississippi	Open
Missouri	Open
Montana	Open
Nebraska	Nonpartisan legislature; open for other offices
Nevada	Partially open
New Hampshire	Open to unaffiliated
New Jersey	Closed
New Mexico	Open to unaffiliated
New York	Closed
North Carolina	Open to unaffiliated
North Dakota	Open
Ohio	Partially open
Oklahoma	Partially closed
Oregon	Partially closed
Pennsylvania	Closed
Rhode Island	Open to unaffiliated
South Carolina	Open
South Dakota	Partially closed
Tennessee	Closed
Texas	Open
Utah	Partially closed
Vermont	Open
Virginia	Open
Washington	Top-two (one ballot)
West Virginia	Partially closed
Wisconsin	Open
Wyoming	Closed

In a partially closed state, the answer can change from one election to the next, because each party decides whether to let unaffiliated voters in. Maryland, Oklahoma and Oregon allow it by law, but NCSL reports that both major parties there currently admit members only.

What States Can Independents Vote in Primaries?

In 33 states, a voter registered with no party can vote in a party primary without asking any party’s permission. That covers the 15 open states, the 5 partially open states, the 8 states open to unaffiliated voters, and the 5 states with one-ballot or mixed systems. Choose your state in the finder above to see the exact rule.

The rules for how you take part differ. In the 8 open-to-unaffiliated states (Arizona, Colorado, Maine, Massachusetts, New Hampshire, New Mexico, North Carolina and Rhode Island), you pick one party’s ballot and party members cannot cross over; in New Hampshire you declare a party at the polls. In the 5 partially open states (Illinois, Indiana, Iowa, Nevada and Ohio), your ballot choice is public or can count as joining that party.

Independents are shut out in 7 of the 8 closed states: Delaware, Florida, Kentucky, New Jersey, New York, Pennsylvania and Wyoming. Tennessee, the other closed state, has no party registration, so a voter joins a primary by declaring allegiance to the party at the polls. In the 9 partially closed states, each party decides every cycle; Maryland, Oklahoma and Oregon currently admit party members only. To vote in a closed primary, you have to register with the party before your state’s switch deadline in the table above.

Can You Vote for Both Parties in a Primary?

No. In a partisan primary, you choose one party’s ballot for that election, even in an open-primary state. Open primaries let you pick either party’s ballot privately, and you can pick a different party next time, but you cannot vote in both parties’ contests in the same primary.

The exception is a one-ballot primary. In Alaska, California and Washington, every candidate for an office is on the same ballot, so you can vote for a Democrat for one office and a Republican for another. Nebraska’s legislative races and most Louisiana state races also put every candidate on one ballot. Mississippi’s law makes the one-party rule explicit: no one may vote in one party’s primary after voting in another party’s primary on the same date (NCSL).

Who Shows Up for Primaries

Primary turnout is low in every kind of state. Barely one in five eligible voters casts a ballot, and that group decides most safe seats. Between elections, voters in some states have one more route, a recall election.

Midterm primary turnout has not cleared 22% in the last four midterms.

Midterm Primary Turnout, 2010 to 2022

Category	Value
2010 midterm primaries	18.3%
2014 midterm primaries	14.3%
2018 midterm primaries	19.9%
2022 midterm primaries	21.3%

Share of all eligible voters who cast a primary ballot. Source: Bipartisan Policy Center, 2022 Primary Turnout report.

The spread between states is wide. The Bipartisan Policy Center found that Kansas led in 2022 at 48%, with an abortion-rights referendum on the ballot. Virginia, New York, Connecticut, Delaware, and Mississippi each had 12% or less.

Primary Voters Look Different From the Rest of the Electorate

The people who do vote are not a cross-section of their district. Brookings researchers found that primary voters tend to be older, better educated, and wealthier than their neighbors, and that they are strong partisans who see themselves as more ideological than most voters.

States with more open primaries drew more voters in 2022, but the gap is a few points.

2022 Primary Turnout by Primary Type

Category	Value
Open, top-two, or top-four states	24.5%
Semi-open states	21.5%
Closed states	20.7%

Average share of eligible voters who cast a 2022 primary ballot, by BPC's grouping of states. Source: Bipartisan Policy Center, 2022 Primary Turnout report.

BPC’s own analysis puts the gain from switching at close to 2 percentage points for a closed-to-open change and about 3 points for a move to top-two or top-four. That helps, but it does not close the gap between a 21% primary and a November election.

2026 Primary Election Calendar

Nearly all of the 2026 primaries are over. Arkansas, North Carolina, and Texas voted first on March 3, and Delaware closed the regular calendar on September 15. The latest runoff date on NCSL’s calendar was Oklahoma’s, August 25.

One primary is still ahead. A 2026 Louisiana law, HB 842, moved the state’s U.S. House primary to November 3, with the general election for those seats on December 12, according to NCSL’s 2026 primary calendar.

The calendar’s lesson for the next cycle is the deadline, not the date. In closed and partially closed states, the party-switch deadline can fall months before the primary, so a voter who wants in has to act long before the campaign starts. You can check or update your registration at vote.gov.

Where Primary Reform Stands Now

For a few years the momentum ran toward opening primaries. Alaska adopted a top-four primary in 2020, and Colorado already let unaffiliated voters into party primaries. The 2024 election turned that around, when voters in five states rejected measures to open their primaries, and 19 states now ban the ranked-choice general elections that top-four and top-five systems depend on.

Where Each Primary Reform Stands

As of September 25, 2026

• Alaska top-four primary Law, repeal on the ballot

  Kept in 2024 by 737 votes, 50.11% to 49.89%. Ballot Measure 2 on November 3, 2026 would bring back party primaries and end ranked-choice voting. (source)

• Ranked-choice voting bans Law, 19 states

  In March 2026, Ohio became the second state that year to ban it, after Indiana. (source)

• Louisiana party primaries for Congress Law, state races stay all-candidate

  U.S. Senate primary held May 16, 2026. The U.S. House primary moved to November 3 under HB 842. (source)

• Nevada top-five primary (Question 3) Ended, rejected in 2024

  Approved in 2022, then rejected on the required second vote in November 2024, so it never took effect.

• Colorado top-four primary (Proposition 131) Ended, rejected in 2024

  Would have replaced party primaries with one all-candidate primary and a ranked-choice general.

• Idaho top-four primary (Proposition 1) Ended, rejected in 2024

  Would have ended closed party primaries and added a ranked-choice general.

• Arizona single primary (Proposition 140) Ended, rejected in 2024

  Would have put every candidate on one primary ballot.

• South Dakota top-two primary (Amendment H) Ended, rejected in 2024

  Would have replaced party primaries for state offices with a top-two primary.

Source: Alaska Division of Elections; Alaska Beacon; Ballotpedia; NCSL

The bans matter beyond ranked-choice voting itself. Ranked-choice voting is the general-election half of the top-four and top-five models, so a ban closes off that path to an open primary as well. In most of the country, the partisan primary, open or closed, is now the fixed starting point for any reform.

What Open Primaries Do and Do Not Fix

Opening a primary is not the same as making a race competitive. An open primary lets more people vote, but where one party dominates a district, the winner still comes from that party. Turnout and gerrymandering are separate problems, and fixing one leaves the other in place.

The turnout gains are also smaller than the debate suggests. BPC found that primary type fell short of statistical significance in its simplest models and approached it only in the stronger comparisons of states that switched systems.

Ranked-choice voting and open primaries are different reforms, though the 2024 ballot measures usually bundled them. A state can open its primary without ranking candidates, and it can rank without opening. Voters who rejected the combined packages were not necessarily rejecting either piece on its own.

Closed primaries are not always the barrier they look like. In a competitive district, independents still get a real vote in November. The lockout bites hardest where one party already holds the seat, which describes most of the map.

The case for closed primaries rests on the parties’ own rights. In California Democratic Party v. Jones (2000), the Supreme Court struck down California’s blanket primary 7-2, finding it forced parties to let voters who had refused to affiliate with them pick their nominees. Supporters of closed primaries also worry about crossover voting, where members of one party vote in the other’s primary to help a weaker candidate. The Independent Voter Project answers that unaffiliated voters pay for these elections with their taxes and still cannot take part.

Frequently Asked Questions

What states can independents vote in primaries?
In 33 states, a voter registered with no party can vote in a party primary without a party’s permission: every open, partially open and open-to-unaffiliated state, plus the one-ballot systems. In the 8 closed states they cannot, and in the 9 partially closed states each party decides; in Maryland, Oklahoma and Oregon, neither major party lets them in now.

Can you vote for both parties in a primary?
No. In a partisan primary you choose one party’s ballot for that election, even in open-primary states. The exception is a one-ballot system: in Alaska, California and Washington, every candidate is on the same ballot, so you can pick a Democrat for one office and a Republican for another.

What is the difference between a primary and a caucus?
A primary is an election the state holds, where voters cast secret ballots. A caucus is a meeting run by a political party at the county, district, or precinct level; some caucuses vote by secret ballot, and in others supporters form groups by candidate. In presidential contests, most states hold primaries and several hold caucuses.

What is a runoff primary?
Some states require a primary winner to take a majority of the vote. When no candidate does, the top two meet again weeks later in a runoff. Two set a lower bar: North Carolina holds one only if the runner-up asks and the leader got under 30%, and South Dakota only if no one reaches 35% in a race with three or more candidates. Ten states set runoff dates for 2026, from Arkansas on March 31 to Oklahoma on August 25, including Texas, Georgia, and Alabama.

What You Can Do

1. Check your party registration now, not in 2028. Look up your status at vote.gov. In Kentucky the switch deadline is December 31 of the year before the primary, and in New York it is February 14.
2. If you live in Louisiana, vote in the U.S. House primary on November 3. It shares the date with the general election for other offices, and the House general follows on December 12.
3. If you live in Alaska, read Ballot Measure 2 before November 3. It would repeal the top-four primary as well as ranked-choice voting. The ranked-choice voting explainer covers both sides.
4. Vote in your next primary. In a safe district, the primary is the election. Skipping it means someone else picks your representative.
5. Back primary reform in your state. Represent.Us and Unite America work on opening primaries at the state level.

Read the gerrymandering explainer to see why so many districts are safe, and the Election 2026 series for what is at stake this cycle. Your state page covers local races and issues.