1

Schwarzenegger Institute Report

University of Southern California | Price School of Public Policy

Evaluating California’s Top-two Primary: Candidates are More Bipartisan and More Responsive to Independent Voters in Top-two

Primaries than in Closed Primaries

March 2016

Christian R. Grose

Associate Professor University of Southern California

Price School of Public Policy Dept. of Political Science

cgrose@usc.edu

Schwarzenegger Institute Report University of Southern California

Price School of Public Policy

2

SIGNIFICANT FINDINGS

Evidence suggests the top-two primary in California is associated with

candidate willingness to engage in bipartisan appeals to voters across partisan

lines.

Candidates running in states with top-two primaries or open primaries are

more responsive to independent voters than are candidates in states with closed

primaries.

Candidates running in states with top-two primaries are more responsive to

opposite-party voters than are candidates in states with closed primaries and

open primaries.

Candidates in 2014 in the top-two states of California and Washington

presented more bipartisan messages to all voters than did candidates in closed-

primary and open-primary states.

Closed primaries have candidates who are the least likely to present bipartisan

appeals across party lines to voters of different partisan backgrounds.

3

Political reforms such as top-two and open primaries have garnered significant interest among

reformers interested in creating electoral environments where candidates appeal to voters across the

partisan spectrum. Closed primary systems – where only voters registered with the political party can

vote for candidates running in that party’s primary – have been criticized by some good-government

advocates. Proponents of top-two primaries – where all voters vote simultaneously in the primary

regardless of the voters’ party affiliations – claim that the top-two primary is an electoral institution that

changes candidate behavior, incentivizing candidates to be more bipartisan in their appeals to all voters

regardless of party. In 2012, California held its first elections using the top-two primary. This new

primary system came about due to the endorsement and advocacy of Governor Arnold Schwarzenegger,

other elected officials, and political reformers; and passed by voters at the ballot box.

Has the top-two primary encouraged candidates to reach across the aisle to voters of differing

party affiliations? Is candidate responsiveness to Democratic, Republican, and independent voters

different in top-two primary systems than in closed and open systems? This policy report offers answers

to these questions by examining candidate behavior in California and Washington – where the top-two

primary is used – and comparing it to candidate behavior in other states using closed and open primary

systems.

I examine candidate responsive to voters in 13 U.S. states with different primary systems. I look

at California and Washington – which both use the top-two primary – and compare candidate behavior in

those states to other states with pure-closed and pure-open primaries.1 I find that candidates in top-two

primary states are much more likely to engage voters who do not share the same party affiliations.

Democratic candidates, for instance, in California and Washington, are much more likely to engage

Republican voters than are comparable candidates in states with closed or open primaries. In addition,

1 Closed primaries are those where only voters registered with the party in which the candidates are running can

participate in the first round (e.g., Democratic voters only can vote in the Democratic primary). Open primaries are

those where voters of any party (Republican, Democratic, or independent) can vote in one of the first-round partisan

primaries (e.g., Democratic, Republican, and independent voters can vote in the Democratic primary but there is also

a concurrent and separate Republican primary). Top-two primaries are those where all candidates of all parties

compete simultaneously against one another in the first round and all voters of any party can participate. The top-

two vote getters advance to the general election, regardless of the candidate party affiliations.

4

candidates in top-two primary states are much more likely to present bipartisan messages to all voters

regardless of partisan affiliation; and this is not found among candidates in closed-primary states. The

conclusion is that candidates in top-two primary states are much more bipartisan in their presentation to

all voters than are candidates in states with other primary systems.

Public Policy Advocates of the Top-two Primary Claim Candidates Seek Crossover Votes

Primary systems are likely to affect candidate behavior. In closed primary systems, candidates

have incentives during the primary to focus just on same-party voters and mobilize the base. There is no

need for candidates in closed primaries to reach beyond partisans to secure a nomination. In primary

systems where all voters can potentially participate (open primaries and top-two primaries), candidates

may have incentives to reach out to voters regardless of the partisan backgrounds of the voters during

primary elections. This logic has driven some elected officials and good-government advocates to push

for increasing use of open or top-two primaries in U.S. elections.

Advocates of primary reform in the U.S. have argued that open or top-two primaries will increase

the likelihood that candidates will reach across party lines to appeal to independent and crossover voters.

When primaries are closed to all voters except for registered partisans, advocates claim that a “[closed]

partisan primary system forces candidates to pander to the extreme wing of their party to win primaries.”2

Closed primaries limit participation to same-party voters, which obviously affects which voters can

participate at the first-round nomination stage. Some opponents of closed primaries have sought to

replace them with open primaries, where all voters can choose to participate in either the Democratic or

Republican primary nomination elections. For instance, Senator Charles Schumer (D-NY) endorsed open

primaries, noting positively that Republican Sen. Thad Cochran appealed directly to Democratic voters in

Mississippi’s hotly-contested 2014 open primary.3

Other advocates of primary reform have not called simply for the elimination of closed primaries,

but have specifically suggested that the top-two primary system best incentivizes candidates to cross party

2 Samantha Young, “Schwarzenegger: More States Should Open Primaries.” Associated Press 9 June 2010.

3 Charles Schumer, “End Partisan Primaries, Save America.” New York Times 21 July 2014.

5

lines when appealing to voters. The most recent state to adopt the top-two primary is California, where it

passed as a ballot proposition in 2010 and was first used in 2012. In advocating for California’s top-two

primary to be adopted in other states, former governor Arnold Schwarzenegger (R-CA) argued that

“candidates for office are forced to appeal to all voters” under the top-two primary. Echoing this claim,

the L.A. Times endorsed the ballot proposition to change California’s primary rules in 2010 by asserting

“Candidates would have to appeal from the beginning to a broad swath of the electorate instead of just

their parties’ hardliners.” The two major parties in California opposed the top-two primary ballot

proposition in 2010 (as did the two major parties in Oregon in defeating a top-two primary proposition in

2014). Some claim this opposition was because incumbents preferred running and winning in closed

primaries by appealing to same-party voters they already cultivated in previous elections.4

Academic Conventional Wisdom: A Mixed Impact of Primary Type on Candidate Behavior

What does political science say about the claims of advocates and critics of primary reform in

regards to candidate strategies under different primary systems? Theoretically, median voter logic in a

one-shot primary election might imply that candidates will appeal to independent and possibly even

different-party voters when more voters can participate in settings such as open and top-two primaries

(depending on the overall distribution of partisans in the district); and that candidates will appeal to a

smaller subset of voters in closed primary elections. However, once two rounds of elections are

introduced to theoretical models of candidate position-taking, under certain conditions (e.g., runoffs or

failure for parties to coordinate on one candidate), the predictions for optimal strategies of candidates are

not as straightforward (see, e.g., Indridason 2008).

Surprisingly, empirical work on primaries in the contemporary U.S. has little to say about how

candidate behavior may change toward voters of different partisan stripes conditional on primary system,

though McGhee (2010), in a review of open primaries in the U.S., suggests that more campaign spending

is needed in order to reach a “broader swath of the electorate” under the top-two primary. Similarly,

Kousser, Shor and Phillips (2014, 16) state that “the new [primary] rules sought to bring lawmakers in

4 Dan Walters. “California’s Top-two Primary has Major Impact.” Sacramento Bee 28 December 2014.

6

line with voters by forcing them to win the support of a broader swathe of the electorate in the primary,

and by changing their incentives in the general election,” though these scholars do not study candidate

outreach toward voters of different partisan backgrounds (they examine candidate and legislator ideology,

finding relatively little change). Alvarez and Sinclair (2015) find that the top-two primary had some

effects, though not always exactly as anticipated.

In this policy report, I seek to examine this puzzle between policy advocates – who expect the

electoral reforms to change elite behavior – and the more muted findings in the extant academic research

in political science and public policy.

Study 1: The Top-two Primary Yields Candidates More Bipartisan and Responsive to All Voters

When running for office, do candidates reach out to voters of different partisan backgrounds,

attempting to persuade independent and different-party identifiers to vote for them, or do candidates reach

out to same-party voters in a strategy of mobilizing the base? Does this candidate behavior vary

conditional on primary electoral institution type?

The first study summarized in this report asks whether candidates in top-two primaries are

different than candidates in closed and open primary systems. Advocates of top-two primaries have

argued top-two primaries create incentives for candidates to reach out to voters of all party backgrounds.

Democratic candidates should campaign for the votes of Democrats, Republicans, and independents in a

top-two system, while in a closed system, there is an incentive to campaign only among Democratic

voters. Similarly, in closed systems Republican candidates only have incentives to campaign to

Republican voters but have incentives to reach out to all voters in systems such as the top-two.

Furthermore, candidates in top-two systems are likely to be more bipartisan in their messages delivered to

voters.

An Audit Study of Candidates – Who Responds to Independent and Different-party Voters?

To assess whether candidates behave differently in top-two contests than in other primary

contests, candidate responses to voters were measured using an experiment or audit study. The states

7

examined include those using the top-two primary (California and Washington) and eleven other states.5

These other 11 states were chosen as they held primaries on dates relatively close in time to these top-two

states and because they used either pure-closed or pure-open primaries. The states included in the sample

are Alaska (GOP closed primary, Democratic open primary); California (top-two primary); Delaware

(closed primary); Kansas (closed primary); Maryland (closed primary); Minnesota (open primary); North

Dakota (open primary); Nevada (closed primary); Utah (GOP closed primary; Democratic open primary);

Vermont (open primary); Washington (top-two primary); Wisconsin (open primary); and Wyoming

(closed primary).

These states were selected in order to compare candidate behavior in California and Washington

under the top-two system to candidate behavior in open primary systems and closed primary systems

during the 2014 election. In total there were 2,820 U.S. state legislative candidates studied, and the

candidate is the unit of analysis. There was a sample size of 1,022 who ran in open primary elections;

1,251 in closed primary elections; and 547 in top-two primary elections. In total, 1,570 of these

candidates faced at least one opponent in their primary.

Prior to the 2014 primary election day in these 13 U.S. states, all major-party candidates for

office were contacted by email by a citizen who identified either as a Democrat, a Republican, or an

independent. The partisan identification of each citizen was indicated in the message sent to each

candidate, and the message was otherwise similar except for varying the partisan identification of the

voter. The partisan identification of the voter in each message was randomly assigned to be sent to

candidates. Random assignment of a voter’s partisan identification to each candidate means that all other

explanations for a difference in responses by candidates to voters are “controlled for,” in expectation,

through the randomization (Grose 2014).

Each legislative candidate received essentially the same email from a citizen in terms of content,

and the only part that varied was whether the citizen writing the candidate identified as a Democrat,

5 Louisiana also uses the top-two primary, but holds odd-year state legislative elections and thus was not included in

this study of 2014 state legislative elections.

8

Republican, or independent voter. The email messages were sent to candidates at the same time right

before each primary election day vote. For more details regarding the message sent to candidates and the

research design, see Grose (2015). The study is novel precisely because candidates were asked by voters

of different partisan backgrounds to respond to a query right before Election Day – and the random

assignment of voter partisanship means that any differential in response by candidates to voters of

different partisan backgrounds is only due to the party of the voter. I am then able to compare differential

responses to voters of different partisan backgrounds across top-two primary contests, open primary

contests, and closed primary contests. We cannot know whether the candidates themselves personally

responded to the emails, or whether their staff and volunteers did. In some instances, it was clear that the

actual candidate responded but in others it likely was a staff member.6

Results: Candidates in Top-two Primaries More Responsive to Voters of All Party Backgrounds

The full results of the academic study are available in Grose (2015), but are summarized here for

a policy audience. Top-two states have candidates that are much more likely to be responsive to voters

regardless of their party identifications. As shown in Table 1, in top-two primary states, candidates are

just as likely to reach out to voters who share the candidate’s party affiliation as to independent voters. In

California and Washington, where the top-two primary is in use, 51.4% of candidates were responsive to

a voter of the same party, and 50.2% of candidates responded to a voter who was independent. Similarly,

in top-two contests, 48.5% of voters who were of the opposite party of the candidate nevertheless were

responded to by the candidates. None of these differences are statistically different, suggesting that state

legislative candidates in top-two primary states do not discriminate among voters based on partisanship

when it comes to seeking their votes. Candidates in top-two states are just as likely to respond and seek

the votes of Democrats, Republicans, and independent voters, as was predicted by advocates of reform.

6 Even in those campaigns where staff are responding to voter queries on behalf of candidates, the differential in

response by staff is meaningful. Constituents will still view the response as from the campaign even if authored by

staff, and the strategies of candidates are of course determined by staff in conjunction with candidates.

9

Table 1 also displays the responsiveness results for closed-primary and open-primary candidates.

In closed primary states, candidates generally are less responsive to voters than in top-two-primary states,

meaning that candidates in closed-primary systems do not bother reaching out to different-party and

independent voters. Candidates in closed primary states are 10 percentage points more likely to be

responsive to same-party voters than different-party voters. When a citizen with a shared party affiliation

contacted a candidate in a closed-primary state, 42.1% of candidates responded. However, when the voter

was an independent or a different party than the candidate, the candidate responded much less frequently

(32.7% to independents and 32.8% to different-party voters). The evidence suggests that closed primary

systems discourage candidates from reaching out and campaigning across partisan lines. What is

somewhat surprising is that many of these closed-primary candidates faced minimal or no primary

opposition. Thus, these candidates were likely to advance to the general election, and yet they still did not

respond to voters of different party affiliations who could vote in the general election.

Table 1: Primary election responsiveness - Are candidates in closed primary systems less responsive to

independent and different-party citizens than candidates in open and top-two primary systems?

Candidates who responded to citizen in...

% candidates

responding to voter

Voter is same party

as candidate

% candidates

responding to voter

Voter is independent

% candidates

responding to voter

Voter is different

party than candidate

Closed primary elections

42.1%

32.7%

32.8%

Open primary elections

38.8%

40.1%

30.5%

Top-two primary elections

51.4%

50.2%

48.5%

Not surprisingly, in open-primary systems, candidates were statistically as likely to reach out to

independent voters (40.1%) as same-party voters (38.8%; see Table 1). However, open-primary

candidates were less responsive to different-party voters (30.5%) than same-party voters – even though

different-party voters can participate in the open-primary states in any party’s primary. This result is

explained by the fact that in open primaries any voter can participate in either party primary, but they

10

must choose one primary in which to vote. Thus, candidates assume that different-party voters are not

likely to participate in the opposite party primary. In contrast, in the top-two primary, voters participate

simultaneously, and thus candidates are equally willing to seek the votes of Democrats, Republicans, and

independents.

Comparing closed primary and top-two primary systems, it is clear that in 2014, candidates in

top-two primary contests were much more likely to reach out to voters across party lines while candidates

in closed-primary contests did not reach out across party lines. Top-two primaries are also more likely to

result in candidates reaching out to different-party voters than in open primary systems. The results

suggest that top-two primary candidates are much more likely than both closed and open primary

candidates to reach out to all voters regardless of partisanship.

Candidates in Top-two Primaries: Bipartisan Messages to Voters of All Partisan Backgrounds

In addition to looking at overall responsive by candidates in top-two, open, and closed primary

systems, I also examine whether the candidates present bipartisan messages to voters when they are

contacted. Two research assistants read and coded every message that each voter received from each

candidate in the 13 U.S. states in the study. They coded the messages as including a bipartisan appeal to

the voter; or not including a bipartisan appeal to the voter. An example of a bipartisan appeal from a

candidate to a voter, which came from a candidate running in California, is as follows:

“Thank you for your question. I served three terms in the California State Assembly,

worked for two senators and was appointed to lead a state agency by both a Democrat and

Republican Governor. I have a long history of working across the aisle to solve problems and

worked with my colleagues to toughen laws against sexual predators, improve nutrition in schools

and to increase access to funding for small business owners. While we sometimes experience

gridlock, on many issues we can find common ground if we focus on solutions instead of who

will get credit….”

An example of a candidate message that was not bipartisan, sent by a candidate running in a closed

primary, is as follows:

“I am a Republican and only Republicans can vote for Republican candidates in the

primary…. I cannot think of a single Democrat idea that I would vote for.”

11

If advocates supporting top-two or open primaries are correct that these systems encourage more

bipartisanship in campaign appeals, then we should expect to find more bipartisan messages in candidate

responses to voters – regardless of whether the voter is a Democrat, Republican, or independent. In closed

primary systems, there may be less bipartisanship generally and it may be tailored to certain voters.

Table 2 shows that bipartisan appeals were not very common in closed-primary systems, and that

candidates running in closed primaries were infrequently likely to make bipartisan appeals – even when

communicating with voters who were of a different party background. Only 31.6% of closed-primary

candidates communicating with a voter sharing their partisanship made a bipartisan appeal, and 42.6% of

candidates in closed systems made bipartisan appeals to voters of a different party. Candidates in closed

systems did slightly tailor their messages to voters of different-party backgrounds, though generally these

candidates were not bipartisan to any type of voters.

Table 2: Primary election candidate messaging - Are candidates in closed systems less bipartisan in

campaign messages than candidates in open and top-two systems, conditional on voter type?

% candidates

presenting bipartisan

message to voter

Treatment:

voter is same party as

candidate

% candidates

presenting bipartisan

message to voter

Treatment:

voter is independent

% candidates

presenting bipartisan

message to voter

Treatment:

voter is different

party than candidate

Closed primary elections

31.6%

39.7%

42.6%

Open primary elections

35.7%

38.8%

50.5%

Top-two primary elections

47.3%

52.2%

47.6%

In open-primary systems, Table 2 reveals that candidates often gave bipartisan messages to voters

who were from the opposite party of the candidates (50.5% of voters received a bipartisan message from a

candidate of a different party in an open primary system). However, open primary system candidates did

not make bipartisan appeals in large amounts to same-party and independent voters (only 35.7% of same-

party voters and 38.8% of independent voters received a bipartisan appeal). To summarize, candidates in

12

open primary systems say one thing to voters of a different party than they do to same-party and

independent voters. Thus, open primary systems encourage some bipartisan appeals from candidates, but

it is targeted so that candidates say different things to different voters.

Finally, in top-two systems, there is evidence that candidates make a large percentage of

bipartisan appeals to all types of voters. Unlike in open and closed systems, there is no tailoring of

bipartisan messages. Top-two candidates are as likely to be bipartisan in their messages to same-party,

different-party, and independent voters (the percentage of bipartisan appeals from top-two candidates

ranged from 47.3-52.2%, depending on the partisanship of the voter, and these values are statistically

indistinguishable). Thus, the top-two primary encourages candidates to be bipartisan to all voters,

especially when compared to open and closed party systems.

To summarize, the results of this study of U.S. state legislative candidates are clear. Candidates

behave differently in top-two primaries. Candidates for state legislative office are more bipartisan and

more responsive to all voters of all partisan stripes. Candidates in closed primaries are least responsive to

independent and different-party voters and least bipartisan, especially to voters who do not share their

party affiliations.

Conclusion

The results of study show that the top-two primary is associated with meaningful differences in

candidate behavior. Candidates are much more responsive to independent and different-party voters

when running in top-two state contests than when running in closed primary states. In addition, top-two

primary candidates are much more bipartisan in their appeals to all voters – Democratic, Republican, or

independent – than are candidates in closed and open primary systems. The key takeaway is that the top-

two primary encourages candidates to be responsive to all voters across party lines.

The analyses strongly suggest that the top-two primary yields different candidate behavior than

that found in closed or even open primary systems. The top-two primary – more than both closed and

open primaries – influences candidates to engage in bipartisan appeals to voters across party lines.

Further, closed primary candidates, in particular, infrequently engage in bipartisan appeals to voters.

13

Furthermore, candidates running in top-two primary states (California and Washington) are much more

responsive to opposite-party voters than candidates in states with closed and open primaries. Both open

and top-two primaries encourage candidate responsiveness to independent voters, but closed systems do

not.

While these results suggest there is support for advocates’ claims regarding the top-two primary,

there are limitation to this study. For instance, it is possible some other state-specific factor beyond

primary type could also explain the results. Additional research should be conducted analyzing candidate

position-taking, competition, and other components of the electoral process. In addition, this study could

be replicated in additional settings and elections to see if these results persist.

Works Cited

Alvarez, R. Michael and J. Andrew Sinclair. 2015. Nonpartisan Primary Election Reform: Mitigating

Mischief. New York: Cambridge University Press.

Grose, Christian R. 2014. “Field Experimental Work on Political Institutions.” Annual Review of Political

Science 17:355-70.

Grose, Christian R. 2015. “Can Primary Electoral Institutions Increase Bipartisanship in Legislative

Campaigns?” Paper presented at the American Political Science Association, San Francisco, CA; and the

European Political Science Association, Vienna, Austria.

Indridason, Indridi. 2008. “When to Run and When to Hide: Electoral Coordination and Exit.” Economics

and Politics 20:80-105.

Kousser, Thad, Justin Phillips, and Boris Shor. 2013. “Reform and Representation: Assessing California’s

Top-two Primary and Redistricting Commission.” SSRN working paper.

http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2260083

McGhee, Eric. 2010. “At Issue: Open Primaries.” Public Policy Institute of California.