Why Democrats can vote in Republican primaries… sometimes

Posted By: FiscalNote

In July 2014 Mississippi’s senior U.S. Senator, Thad Cochran, won the Republican primary runoff against Republican state Senator Chris McDaniel. Before the runoff, Cochran made explicit appeals to black Mississippians, who traditionally vote Democrat by large margins, to cross over and vote for him in the GOP primary as permitted by Mississippi state law. In the runoff, voter turnout increased by an average of 40% in counties with a majority black population – counties Cochran won. In other counties, the increase in voter turnout was much lower: about 16%.

Types of Primaries in the States

The most common type of primary is an open primary, in which anyone may vote for either party. Some states have a combination of types, wherein the Republicans and Democrats hold different types of primaries.

Type #
Open Primary 19
Closed Primary 18
Semi-Closed Primary 7
Top Two Primary 2
Combination 5

After the primary, McDaniel claimed that that the Republican primary was “decided by liberal Democrats.” Since anyone, regardless of party, can vote for Republicans in the Mississippi primaries, no statistics are taken of voters’ party affiliations, but a Wall Street Journal poll and FiveThirtyEight’s analysis suggest that traditionally Democratic voters may well have boosted Cochran’s outcome. One pro-Cochran group’s ad in a Mississippi newspaper appealed to Democratic readers: “We’re asking Democrats to cross over and vote in the Republican primary to ensure our community’s interests are heard.”

Mississippi is one of 27 states that allow people other than registered party members to vote in the Republican and Democratic primaries. Primary rules for Congressional elections vary widely by state, with four main types of primaries: open, closed, semi-closed, and top two. See the key below for descriptions of the four types, as well as the numbers of states with each type.

Legal Challenges to Primary Systems

In 1996, a voter referendum changed California primary rules to create a fifth type of primary: the blanket primary. Under this system, all candidates were listed on all ballots, and voters were free to choose a Republican in one race and a Democrat in the next. The top vote-getter from each party on this blanket ballot advanced to the general election.

In 2000, the Supreme Court held that the blanket primary violates a political party’s freedom of association under the First Amendment, and California switched to a different system. Two years later, a Georgia Democrat who lost her primary attempted to use this Court decision to challenge to the open primary system, but the district court threw the case out, ruling that blanket and open primaries are two different systems. Open primaries, the court said, are legal because they require a voter to choose candidates from one particular party for all races.

Small parties, including the Libertarian and Green parties, are now challenging California’s new top two primary system, arguing that it keeps their parties’ members from reaching the general election ballot. And a handful of residents are challenging New Jersey in court, arguing that the state’s closed primaries, which require residents to register with a party in order to vote in that party’s primary elections, unconstitutionally disadvantage independent voters.

Do Voters Sabotage the Opposing Party in Primaries?

How often, as Mississippi Senate candidate McDaniel argued, do liberal voters actually decide a Republican primary, or conservative voters a Democratic one? Statistics are hard to find because states with open primaries do not record whether voters’ ideological preferences match up with the ballot they choose. The majority of the evidence, however, indicates that primary crossover, in which a voter from a certain party votes in the primary of the opposite party, is relatively rare.

When California had a system that allowed crossover voting in the 1990s, multiple studies by political scientists John Sides, R. Michael Alvarez, and Jonathan Nagler found that crossover voting was not widespread and thus failed to influence election outcomes. Other studies indicate that even when voters identify as independent, they tend to pick the primary ballot of the party that more closely aligns with their political beliefs.

When voters do cross over, studies have found that most do so in order to cast their vote in a competitive contest or to vote for a familiar candidate, such as an incumbent or a particularly charismatic newcomer. These studies found no evidence of systemic abuse of the open primary system for the purpose of sabotaging the opposing party.

Crossover for Sabotage

While scholars have yet to find consistent evidence that open primaries lead to deliberate sabotage, losing candidates have often claimed that the opposing party caused their defeat. In 2002, for instance, Georgia Democratic Representative Cynthia McKinney claimed that thousands of Republicans voted for her primary opponent, Democrat Denise Majette, in McKinney’s 16-point loss.

State-by-State look at Primary type

There are five types of primaries found in the states. They differ in whether or not a party allows anyone to vote for it's candidates.

Type of Primary Who may vote in each party' primary States with this type of primary
Open Primary
(19 states)
Anyone may vote in either party's primary AL, AR, GA, HI, IN, LA, MI, MN, MS, MO, MT, ND, OH, SC, TN, TX, VT, VA, WI
Closed Primary
(17 states + DC)
Only registered members of the party may vote in each party's primary CO, CT, DE, FL, IA, KY, ME, MD, NV, NH, NJ, NM, NY, OK, OR, PA, WY, DC
Semi-Closed Primary
(7 states)
Registered Democrats may vote in the Republican primary and vice versa, but independent voters may vote in either the Democrat or Republican primary AZ, IL, MA, NE, NC, RI, WV
Top Two Primary
(2 states)
All candidates are listed on all ballots. The top two candidates, regardless of party, advance to the general election CA, WA
(5 states)
Republicans in these states have closed primaries, while Democrats hold open or semi-closed primaries AK, ID, KS, SD, UT

In 2008, influential conservative talk show host Rush Limbaugh told Republicans to launch “Operation Chaos” by voting for Hillary Clinton to prolong the vicious Obama-Clinton Democratic presidential primary contest. Limbaugh’s success is debatable. Huffington Post commentator Sam Stein thought Operation Chaos may actually have had a substantial effect in Indiana, while ABC polling director Gary Langer dismissed the Limbaugh effect, arguing that some Republicans liked Clinton, wanted to vote against Obama, or wanted to participate in a more competitive primary contest.

In 2012, liberal blog Daily Kos attempted its own version of Operation Chaos. Dubbing the plan “Operation Hilarity,” Daily Kos urged its Democratic readers to vote for Republican presidential candidate Rick Santorum in an effort to complicate the primary race for the GOP’s eventual nominee. Santorum’s own campaign also called and emailed Michigan Democrats, encouraging them to vote in the Republican primary in order to cast a vote against Romney. Exit polls showed that 9% of Michigan GOP primary voters in 2012 were Democrats, and that over half of those Democrats voted for Santorum (as opposed to only 37% of Republicans). The push, however, wasn’t enough for Santorum; Mitt Romney won the Michigan primary and, later, his party’s nomination.

In Montana earlier this year, some Republican leaders argued that Democrats had attempted to sabotage their primaries in 2012. On this basis, the party opted not to endorse an open primary system on their official platform.

It’s important to note that, in Mississippi, anyone who voted Democrat in the initial primary was ineligible to vote in last week’s Republican primary runoff. Thus, many Democratic diehards could not possibly have influenced the Republican election for Cochran. On the other hand, because vast majorities of people do not vote in the primaries, many Democrats and liberals who did not vote in the initial primary could have been persuaded to vote for Cochran in the runoff.

Influencing the Other Party’s Primary Election

In 2012, Democratic Party-run Majority PAC spent $1.2 million in ads opposing the most centrist candidate in the Missouri Senate Republican primary, who was viewed as the biggest threat to incumbent Democratic Senator Claire McCaskill. The Democrats attempted to get Republicans to pick candidate Todd Akin, whom they thought McCaskill had the best chance of beating in the general election. McCaskill herself took to TV and radio calling Akin “too conservative,” a thinly veiled attempt to mobilize the conservative Republican base into voting for Akin. The Democrats’ efforts and money proved successful; Akin won the Republican primary, and McCaskill went on to best him in the general election.

It may seem logical to think that the Democratic Party would routinely pour money into the Tea Party’s coffers before the Republican primary, since Democrats have recently performed better against Tea Party candidates than against more moderate Republican ones. Instances of this kind of meddling, however, seem rare. In 2010 and 2012, there were several high-profile Republican Senate primaries that pitted a Tea Partier against a GOP establishment candidate in states where Democrats had a shot at ultimately winning the Senate seat. The most watched of these contests included Senate races in Indiana, Utah, and Delaware in addition to the 2012 Missouri race.

In the three races other than Missouri, there is no evidence that the Democratic Party contributed to the Tea Party candidate, and no evidence of high-profile Democratic leaders “supporting” the Tea Partier for the purpose of sabotaging the Republican primary. Despite this, the Democrat ended up winning the Senate contest in the three races (Indiana, Delaware, and Missouri) where the Tea Partier won the Republican primary.

In fact, Democrats supported the GOP establishment candidate over the Tea Partier in Cochran’s Mississippi primary, seemingly placing their own party at a disadvantage. Democrats were considered to have no shot of defeating Cochran in the general elections, but an outside shot at beating his Tea Party challenger. Despite presumably giving up a shot at a Democratic win, many Democrats rallied behind Cochran in the primary, and several high-profile Democratic leaders, including Mississippi Democratic mayors and state lawmakers, made calls on behalf of Cochran.

Republicans, on the other hand, appear not to give support to very liberal Democratic candidates in the hopes of defeating moderate Democratic incumbents in primaries.

The Consequences of Crossover

Cochran’s primary election victory partially at the hands of Democrats seems a rare example of a case when crossover voting made a difference, even with no hint of sabotage. Now, assuming Cochran cruises to general election victory, it remains to be seen whether his positions will shift to reflect the voters who elected him.

Already, Democratic members of the Congressional Black Caucus (CBC) believe Cochran is in their debt. “Absolutely we have expectations,” said CBC member Rep. Marcia Fudge. Rep. Hank Johnson added, “I’m hopeful he will be responsible and responsive to the voters that pushed him over the top.” NAACP Mississippi state president Derrick Johnson specifically wants Cochran to oppose voter ID laws and to support historically black colleges in order to be responsive to his electorate.

Some positions now asked of Cochran are more liberal than stances he has traditionally taken. As a result of his courting crossover voters, Cochran may end up finding himself in a tricky situation, and he may well regret his Democratic outreach. On the other hand, some Democrats’ support of Cochran may soon be forgotten as he returns to his more conservative base, offering other establishment or moderate GOP politicians a blueprint for how to defeat the Tea Party in their own primaries.