Pros and cons
Last updated:
The main pro of open primaries is that every registered voter can help choose nominees; the main con is that parties lose control over who picks their candidates.
The case for open primaries rests on access: in 2024, 87% of congressional races were decided in the primary, yet independents made up just 11% of those decisive voters.
Open primaries widen who chooses nominees and remove party-membership barriers; the cost falls mostly on parties, which give up exclusive control and face possible crossover voting.
For
Against
Parties prefer closed primaries because they keep the choice of nominee with registered members. That guards against crossover voting, rewards loyal members, and gives the party a clear list of supporters to organize.
Parties also point to the Constitution. In California Democratic Party v. Jones (2000), the U.S. Supreme Court held that forcing parties into a blanket primary violated their freedom of association. Reform supporters answer that primaries are run and funded by the state, so every eligible voter should have access, which is why nonpartisan systems that do not pick party nominees have survived in court.
Numbers
Only 7% of voting-age Americans cast ballots in the primaries that decided 87% of 2024 congressional races. Independents were 39% of the voting-age population but 11% of those voters, and moderates were 47% of adults but 11% of decisive primary voters.
Turnout
All three nonpartisan primary states, Alaska, California, and Washington, were among the 12 states that met a 30% primary turnout goal in the 2026 midterms. California was one of only two states to reach 35%. Oregon, a closed state, also reached 35%, so primary type is one factor among several.
Crossover
Raiding is when voters loyal to one party vote in the other party's open primary to boost a weaker candidate. It is the objection parties raise most often. Semi-closed rules block it by limiting each party ballot to members and unaffiliated voters.
Verdict
For voters who value access, yes: open and nonpartisan primaries give every registered voter a ballot in the round that often decides the race. A closed primary fits better only when the goal is a party nominee chosen strictly by its own members. Compare open vs closed primaries.
The first step is supporting open primaries for every voter. Next, see how More Choice Voting builds on them.
The main pro is that every registered voter, including independents, can help choose nominees in elections paid for with public funds. Supporters also point out that candidates must appeal to a wider electorate. That matters because 87% of congressional races in 2024 were effectively decided in the primary.
The main con is that parties lose control over who picks their nominees. Critics also raise the risk of crossover voting, where members of one party vote in the other party's primary to influence its result. Some argue open primaries weaken party identity. These concerns are why many parties defend closed systems.
Parties prefer closed primaries because they keep nominee selection with registered members. That protects against crossover voting, rewards loyal members, and gives parties a clear list of supporters. Parties also cite their First Amendment freedom of association, which the Supreme Court relied on in California Democratic Party v. Jones (2000).
Party raiding is when voters loyal to one party vote in the other party's open primary to help a weaker candidate win its nomination. It is the most common objection parties raise to open primaries. Semi-closed and closed rules are designed to block it by limiting who can request each party ballot.
They give moderates more access. 47% of voting-age Americans identified as moderate in 2024, yet just 11% of decisive primary voters did. Opening primaries to every voter widens the electorate that picks nominees, which is the change supporters argue gives moderates a louder voice.
States with the widest primary access post some of the strongest turnout. All three nonpartisan primary states (Alaska, California, and Washington) were among the 12 states that reached 30% primary turnout in the 2026 midterms. Oregon, a closed state, also cleared that mark, so other factors matter too.
