The vast majority of American elections boil down to a duel: a battle between two candidates, two platforms, and two sides — Democrat and Republican. For most voters registered as team ‘D’ or ‘R,’ the decision in an election is fairly straightforward and predictable. But for millions of independents, thrown into the fight without certainty of which side to join, the choice lies between two candidates who were chosen in a party member-only primary.
Independents are often a decisive voter bloc in contested elections, exemplified recently by their swing toward Trump in 2024, especially in key battleground states. In many states, however, independents have no say in what the contest looks like before Election Day. In 2024, over 23.5 million independent or non-affiliated voters across 22 states were excluded from primary elections by some form of a closed primary or caucus, which either exclude or allow parties to exclude independent voters from participating in the primary election. As voters across the spectrum wonder how the fight became so polarized, and as parties strive to conquer the middle ground, state laws continue to keep out the large bloc of voters with the power to make all the difference.
Closed primary elections harmfully exclude the voices of millions of Americans in a decisive stage of the electoral process. By opening up primary elections to these key voters, states can combat the rise of political polarization and ensure that candidates better reflect the full electorate, ultimately improving both political prospects for parties and accurate representation for the country.
Open or Closed? Independent Voters in Primaries
Despite the dominance of the two-party system, Independent voters comprise a substantial portion of the electorate. In 2010, 24.1% of registered voters in states with closed primaries or caucuses that track party affiliation refrained from picking a side, identifying instead as independent or unaffiliated. Since 2010, that proportion has increased by nearly 20%, highlighting the growing share of independents in states that continue to exclude them from primaries.
While independent voters are ideologically diverse and tend to lean toward one party, the majority are “moderate” and remain undecided in the days and weeks leading up to every election. The independent vote has tracked with the election outcome in nine of the last 12 presidential elections, and its shifts between elections are even more accurate to broader electoral shifts.
Despite their sizable influence on elections, both in numbers and in ideological position, independent and non-affiliated voters cannot vote in primary elections in many states.
Ten states — Delaware, Florida, Kentucky, Nevada, New Jersey, New Mexico, New York, Pennsylvania, Tennessee, and Wyoming — currently hold fully closed primaries, meaning that only voters who are registered with each party can vote in the party’s primary. Independent or non-affiliated voters cannot vote at all in the primary election stage. Meanwhile, nine states hold partially closed primaries, allowing each political party to choose whether or not it will allow independent voters to participate. Aside from the caucus states, the majority of other states hold some form of open primary, where independent and non-affiliated voters can choose a party primary in which they will cast a ballot.
With 23.5 million registered independent voters unable to vote in primary elections nationwide in 2024, the repercussions of closed primaries are substantial. In the closely-decided primary elections around the country at every level, independent voters could be the tipping point toward a more moderate candidate. Such inclusion would make parties more competitive in the general election and subsequent policies more representative of constituents.
Judging by recent trends in state legislative proposals, reactions to the exclusion of independent voters from primaries are a mixed bag. In 2024, 18 states considered legislation making primaries more open or closed. Eight of those states considered a push to more open primaries, while 10 considered legislation that would make the elections more closed, to varying degrees. As the nation approaches the 2028 election, during which both major parties will hold a competitive presidential primary, the question of how open primaries ought to be will only become more pivotal.
Why Include Independents?
The natural objection to open primaries is quite simple: If voters want to participate in a party’s primary, they can simply register with that party. It’s as easy as checking a box on a form. So why should parties be required to allow independents to vote in their elections, and why should states adjust their laws to accommodate this change?
But this proposed solution fundamentally misunderstands why independents choose not to register with a party in the first place. Though often in the political center, independents are an ideologically diverse set of voters, and their decision not to register with a party reflects more than mere ambivalence or apathy.
One notable factor of voters’ registration choices is that in most states, voter registration data — including party affiliation — is publicly available. There are many valid reasons as to why voter registration data is public, including transparency of the election process and fairness to campaigns, regardless of whether they are currently in power and have access to data. Nonetheless, publicizing this information puts voters’ party affiliations on display for all to see. As such, many Americans choose not to register with a political party because they do not want to make their political views widely accessible. Such a choice is justifiable for many reasons, including avoiding perceptions of partisanship for certain occupations and preserving relationships with those of differing views.
Even in states where voter registration is not public, it is crucial that voters have the right to express their beliefs not only by joining a party, but also by abstaining from party affiliation. Such an expression of independence should not exclude the many engaged independent voters from the electoral process at a pivotal point. Recognizing that “independent” means more than “moderate” is essential for political parties to embrace the role of non-affiliated voters in shaping primary election outcomes and the political discourse at large.
The calculus on opening primaries is straightforward: For those independents who lean toward the party in the first place, the effect of a more open primary will yield minimal change to the status quo while drawing more voters into the party tent. For those independents who are more moderate, participation in the party primary will offer a more accurate picture of electability, which is a crucial aspect of the primary process. To put forth the best and most electable candidate, political parties should push for more open primaries and embrace the option where it is available in states with partially closed primaries.
Regardless of what independents and political parties want, the states ultimately must implement change where primaries are currently closed. Although political parties are private organizations, there is much evidence to support the legality of state-mandated open primary elections. Most importantly, state governments fund and largely operate primary elections with taxpayer dollars. In fact, the Supreme Court has long recognized primary elections as government functions. Furthermore, the states must balance independent voters’ right to free speech and expression through their votes with parties’ rights to conduct their own elections, both of which are certainly valid. This delicate balance has led the Supreme Court to defer much power to the states in deciding primary rules, including the power to allow both open and closed primaries.
In assessing the public interest of open primaries, states must recognize that primary elections are crucial to the broader electoral process itself, which is the foundation of our democratic process. For many subnational races, primary elections practically function as the general elections. In 2024, only 17 House seats flipped party control. Even for competitive elections after the primary cycle, voters are almost always locked into two choices. For independent voters in closed primary states, these choices do not reflect their input at all. By making primary elections more open, states can ensure that independent voters are included throughout the electoral process, especially when the primary stage is the most pivotal.
Beyond just independents, Americans writ large have increasingly lamented the rise of polarization in politics. Some blame primaries for contributing to polarization; others say that extreme candidates coming out of primaries are more a symptom than a cause of polarization. Regardless, allowing independents to vote in primaries combats the polarizing force present in these elections by incorporating voters who are generally more moderate and certainly less partisan. Researchers have indeed found that candidates elected in more open primaries are less extreme, on average. When candidates are less polarized, our political parties and broader discourse are likely to become less polarized and more welcoming of moderate viewpoints. This shift away from the extremes is the solution our fractured country desperately needs.
A Spectrum of Solutions
The question of how open primaries ought to be conducted, and how much freedom political parties ought to have in deciding the rules of primaries, is far from simple, as different states have unique constitutional requirements and differing political dynamics. The approach for a swing state with two strong state parties, for example, will likely differ from a party stronghold. Thankfully, states have a range of solutions at their disposal to satisfy varying conceptions of an open primary process.
The most moderate step toward open primaries for the 10 states that currently require closed primaries would be to switch to the partially closed model. By allowing the parties themselves to choose whether or not to include independent and unaffiliated voters in primaries, the states can at least avoid getting in the way of state political parties that want to include these voters. One criticism of the partially closed primary system is that it can change from year to year and across parties, leaving voters’ access to primaries insecure. Just as the openness of this primary is partial, so too is its assurance for independent voters.
The most powerful way to shift toward open primaries is to simply — well — open them. Open primaries allow independents and unaffiliated voters to choose which party’s election they will vote in. Open primaries ensure that independents have their voices heard in every stage of the election and allow them to choose to vote in the party primary where their contribution will be most impactful.
The “top-two or top-four model” is on the most open end of the primary spectrum. California is well-known for its top-two primary for legislative races. This type of primary election combines the party primaries into a single primary election, where the top two candidates move on to the general election regardless of their party affiliation. Proponents argue that these wide-open primaries promote competitive general election races even in states where one party dominates. Critics contend that in deep red or deep blue states, this model disillusions voters in the minority party. For now, most states are watching from a distance as a handful of states experiment with this model.
Ultimately, opening up primary elections to independent voters is the best path forward for the electorate, the political parties, and the country. While political parties are powerful and useful forces for organizing coalitions in our vast and diverse republic, the nation must not allow the two-party system to box out those who choose not to make or advertise an affiliation. Many voters choose independence from political parties, but no voter is independent from our democracy, and none should be kept from casting their vote when it matters most.
