Can Independents Vote in U.S. Primaries?

Across 15 closed primary states, registered independents lack the right to vote in congressional and state primary elections. State parties can establish rules to permit independents to vote in their primaries, but this is rare. 

According to publicly-available voter registration statistics, there are just over 15.7 million registered independents who lack the right to vote in primary elections in these 15 states. (See full report for a state-by-state breakdown). Further, there are more than 1.8 million voters in closed primary states who are registered with a minor party and are also barred from participating in the major parties’ primaries. A total of 17.6 million registered voters lack a right to participate in taxpayer-funded major party primary elections for congressional and state offices.

The vast majority of these 17.6 million voters are not just shut out of primaries. Because 85% of congressional districts in closed primary states were “safe” in 2022, most of these voters were effectively left without any voice at the ballot box. The primary election was the consequential contest, and given they couldn’t participated, they were denied both fair representation and a mechanism to hold elected officials accountable.  

Presidential Primaries and Caucuses

The problem with closed primaries is even worse at the presidential level. While 15 states have closed congressional and state primaries, an additional seven states — for a total of 22 — hold closed presidential primaries or caucuses. The same rules apply as described above: Independents do not have a legal right to participate in these contests, and their ability to do so is based on the whims of political parties. 

In these 22 states, there are over 23.5 million registered independent voters.^, There are also about 3.5 million voters registered with minor parties who cannot vote in the major party nominating contests. Combined, a total of 27 million registered voters do not have the right to participate in major party presidential primaries or caucuses.

The problem with closed primaries has worsened in recent years as more voters register as independents. Consider the following: The 27 million voters who are not registered with a major party represent 28.8% of all registered voters in the 20 states that hold closed presidential primaries or caucuses (and report partisan voter registration data). In 2010, there were just over 18.5 million non-major party voters in these 20 states who represented 24.1% of all registered voters. In a little over a decade, the share of voters who cannot vote in presidential primaries or caucuses without a party’s blessing has increased by nearly 20%. The raw number of eligible voters barred from participating in taxpayer-funded primaries increased by nearly 8.5 million people. 

To learn more about independent voters and the problem with closed primaries, check out The Unite America Institute's recent report, "Not Invited to the Party Primary."