Photo Credit: Henry McMaster / Flickr

Republican South Carolina Gov. Henry McMaster does not support calls from within his party to close primary elections to registered party members only. He has long pushed back against claims that non-party members will infiltrate the primaries to manipulate outcomes.

It is a tactic called "crossover voting" or "party raiding." The argument is that under an open partisan primary system, large groups of voters from the "other side" will crossover and dilute the power of party members to select their nominees for the general election.

Party leaders in many states, from some Democrats in Hawaii to Republicans in Colorado, have claimed it happens to such an extent that it burdens the parties' constitutional rights. But these parties have never been able to prove it.

In his own state, Gov. McMaster says it doesn't happen and restricting primary access to party members is "an unnecessary impediment,” His stance runs contrary to the state GOP's platform which supports the use of closed primaries.

Claims of Party Raiding Don't Have Sufficient Backing

Parties that have turned to the courts to challenge open partisan primary systems have failed to provide evidence that crossover voting is an actual issue in their state. In the case of Hawaii's Democratic Party, the Ninth Circuit Court said:

"[T]he extent to which Hawaii’s open primary system burdens the Democratic Party’s associational rights is a factual question on which the Party bears the burden of proof.” However, the party had "not developed any evidence” to meet the claimed burden to its rights.

The courts came to the same conclusion in Colorado after the state GOP filed a lawsuit against Proposition 107, which implemented open partisan primaries for all state elections following its passage in 2016.

Research on the matter supports the assertion that there is little to no evidence of substantial crossover voting or party raiding in open partisan primaries.

In their paper, "Analysis of Crossover and Strategic Voting," R. Michael Alvarez at the California Institute of Technology and Jonathan Nagler at the University of California-Riverside looked at the 1988 Super Tuesday primaries and concluded:

"By carefully examining the voters' evaluations of the available candidates, and the voters' perceptions of the candidates' chances of winning both the primary and general election, we have been able to demonstrate that fewer than 2% of voters in the primary engaged in raiding behavior."

Further, the researchers found that in the few cases of crossover voting, the voters' motivations were not to sabotage the party, but "to vote for their first-choice candidate, or, to a lesser extent, to avoid wasting their vote." 

In a more recent analysis, John Johnson at the Marquette University Law School found in 2019 that in Wisconsin, a state with open partisan primaries, "there is no evidence that this kind of voting behavior occurs at all."

Interestingly enough, Johnson found the same percentage of voters said in extensive surveys that they planned to engage in crossover voting as R. Michael Alvarez and Jonathan Nagler, who looked at a much bigger primary picture.

"An identical share (2%) of Republicans and Democrats planned to vote in the other party’s primary," he wrote. "Even if this tiny share of people were indeed 'party raiding,' they cancelled each other out. But there is no good evidence suggesting they weren’t voting in good faith."

Johnson followed this up with a more extensive look at the matter in 2023. In it, he came to the exact same conclusion. 

Will 2024 Be Any Different?

A couple of groups have emerged in South Carolina urging Democrats and independent voters to participate in the February 24 Republican presidential primary and vote for former SC Gov. Nikki Haley in order to weaken former President Donald Trump's candidacy.

LEARN MORE: Independent Voter Guide to the South Carolina GOP Presidential Primary

However, McMaster -- who supports Trump -- doesn't see any reason to think that voters will go along with what these groups want and believes that having an open primary system has helped grow the state's Republican Party. 

“If they want to vote in a primary it’s because they want to go in and vote for somebody,” McMaster told The State.

“That has been a great strength of South Carolina. If you close those primaries, that’s just one more thing that everybody has to register for or maybe carry a card. We think an inviting party is better. Our history has proven that it has worked and that’s how we became the majority party.”

Research backs up McMaster's stance. Existing data suggests that if voters participate in the Republican presidential primary, it is because they want to vote for Trump or they want to vote for Haley. Or, at the very least, they want their vote to matter.

A Simple Solution to the Parties' Concerns

If parties are really concerned about party raiding, there is a simple solution that will protect the associational rights of parties and voters and enhance the voting power and rights of eligible voters across the board: nonpartisan primaries.

Partisan primaries, whether they are closed or open, serve a private interest of selecting party nominees for the general election on the taxpayer's dime. Nonpartisan primaries, like in California and Alaska, include all voters and candidates and narrow the field of qualified candidates, regardless of party.

Put simply, nonpartisan primaries serve a public interest. Parties don't have to worry about associational rights or party raiding because control over these elections is taken out of their hands and put into the hands of voters -- who should have the most power in elections.