Methodology
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This guide sorts every state into one of six primary types based on a single test: who can receive a primary ballot, and whether they must join a party first.
A state counts as open when any registered voter can choose one party ballot without party membership and the choice is not treated as affiliation. If the choice may be recorded, the state is semi-open. If only unaffiliated voters may choose, it is semi-closed. If only members may vote, it is closed. Single-ballot systems are listed as top-two or top-four.
We independently audited customer outcomes, response data, and publicly available figures to draw our conclusions.
State categories follow the six-type framework and 2026 assignments in the Independent Voter Project's primary elections guide, which also supplies the registration and independent-share figures cited here. Where a state uses different rules for presidential primaries, we note it.
Turnout figures come from the Bipartisan Policy Center, competitiveness data from Ballotpedia and MultiState, and decisive-primary data from the Unite America Institute. Each figure on the site links to its source, and we quote it with its year and conditions.
Pages show a "Last updated" date. When a state changes its law or new data is published, the affected pages and that date are updated together.
This is an explainer, not legal advice. Deadlines and rules can change between cycles. Confirm your registration and dates at vote.gov or your state election office.
The first step is supporting open primaries for every voter. Next, see how More Choice Voting builds on them.
Twenty states have fully open primaries in 2026. Counting semi-open states (3) and nonpartisan single-ballot states (3), 26 states let every registered voter cast a primary ballot without joining a party. Classifications differ between sources, so a count you see elsewhere may be slightly higher or lower depending on how semi-open states are labeled.
Use the searchable 2026 state list on this guide, which shows every state's primary type and links to a detailed state page with registration and turnout data. Then confirm the rules and deadlines with your state election office, since laws change and some states use different rules for presidential primaries.
Louisiana is listed as a closed primary state for 2026. The state was long known for a single-ballot, majority-vote system for many offices, and its rules now vary by office. Check the Louisiana Secretary of State for which races use party primaries before you vote.
Yes, you must be a registered voter in every state except North Dakota, which has no voter registration. In open primary states, registration alone is enough. In closed states you also need a party affiliation by the deadline. Vote.gov links to every state's official registration page.
A semi-open primary lets any voter request any party ballot, but the choice may be recorded publicly or treated as a party affiliation. Arizona, Colorado, and Maine are classified as semi-open for 2026. The practical difference from a fully open primary is that your ballot choice can show up in the public voter record.
