Campaigns and elections

Can California’s New Primary Reduce Polarization? Maybe Not.

Mar 27 '13

This is a guest post from Doug Ahler, Jack Citrin, and Gabriel Lenz.  For previous posts on the negligible relationship between primary rules and political polarization see here, here, and here.


According to many pundits and scholars, closed primary elections are a major contributor to the ideological polarization in Congress and state legislatures. By partitioning voters into two ideologically-sorted electorates, they argue, closed primaries incentivize candidates to adopt the positions of voters in their party rather than of their constituency as a whole. As a result, they elect representatives who consistently toe the party line and resist compromise. Advocates of reform, from academics like Morris Fiorina to practitioners like Arnold Schwarzenegger, therefore argue that replacing closed party primaries with a more open nominating process will reduce polarization and its offspring—gridlock and a noxious political atmosphere—by helping moderate candidates.

Are these claims about the consequences of reform valid? To shed further light on the consequences of this reform, we conducted a statewide experiment before California’s June 2012 primaries. As a result of a popular referendum, these elections replaced the closed party primaries with an open ballot that presented voters, regardless of party, with the same list of candidates. The top two vote getters advanced to the general election, thus allowing for a choice between two contenders from the same party. In a study sponsored by the Institute of Government Studies at UC Berkeley, we randomly assigned 2839 registered voters in U.S. House districts where moderate candidates faced more extreme candidates to one of two conditions for electoral choice: (1) the open ballot that would be used in the actual 2012 primary, or (2) the closed primary ballot that earlier elections employed.

For advocates of the reform, the results of this survey experiment are disappointing. If the open ballot did indeed help moderate candidates, they should have won more votes in the open-ballot condition than in the closed-ballot condition. But as shown in the scatterplot below, we find no such evidence: Moderate candidates for the House of Representatives fared no better under the top-two primary than they would have in closed party primaries. The vertical axis plots how much better (or worse) candidates performed among participants randomly assigned to the top-two ballot, while the horizontal axis plots candidate moderateness on a seven-point scale. The results fail to show the upward-sloping trend that advocates of primary reform argue we should see.


Why did the top-two reform fail to achieve its goals? While voters are generally quite moderate and were willing to cast crossover votes (roughly 12% of our participants who voted for a major party candidate did so), they largely failed to discern ideological differences between extreme and moderate candidates of the same party, particularly if they were challengers. In addition to asking about vote choices, we asked respondents to rate the candidates in their districts on a 7-point scale of political ideology. To obtain an objective measure of a candidate’s ideology, we visited her website and placed her on the same 7-point scale of liberalism-conservatism, and also hired 204 workers on Amazon’s Mechanical Turk to do the same rating task. The figures below plot the averages of respondents’ ratings for each candidate against the average of those generated by the “MTurkers.” The first graph includes Democratic candidates and the second Republican candidates.  The lack of correlation between two ratings is striking, as is the reluctance of respondents to place candidates at the extremes of the scale.


Of particular interest in the second graph — which includes only Republican candidates — are the respondent placements for District 24. Abel Maldonado is a well-known moderate politician in California, a former Lieutenant Governor and State Senator, and most importantly, the author and principal advocate of the Top-Two Primaries Act. His potential constituents rated him at roughly 5.25 on the 7-point scale. However, they gave almost the same rating to his fellow GOP challenger Chris Mitchum, a little-known actor and Tea Party candidate who the local GOP endorsed because of Maldonado’s violation of the pledge not to vote for raising taxes. So while Maldonado appears to have benefited from the open primary in the first graph in this post, this was not because voters in his district were attuned to the ideological differences between the two Republicans.

It is worth noting that the top-two primary was implemented in all statewide elections and not just the congressional races described above. We conducted a similar analysis for races for California’s State Senate, the upper house in the nation’s most polarized state legislature. Again, we find no evidence that the open primary helped moderate candidates. And while the open ballot failed to help moderate candidates in House races because voters struggled to identify moderate candidates, it failed in these down-ticket races because few voters even tried to locate the centrists: “Don’t know” accounted for a large majority of ideological ratings given to State Senate candidates. As a possible consequence of this lack of knowledge, voters appear to have relied much more heavily on partisanship in voting for State Senate. Just 5.6% of respondents cast a vote for a candidate from a party other than their own in these races.

While this research implies that open primaries are not the cure for polarization its advocates hoped for, its limitations should be mentioned. Open primaries may still moderate the behavior of elected officials even if voters fail to recognize or explicitly reward such moderation (Bullock and Clinton offer evidence that this generally is not the case.) Alternatively, experience with the new rules may cause both voters and candidates to adapt and gravitate toward the center. This may be especially true in California, where some believe that in the long-run primary reform in conjunction with nonpartisan redistricting will produce a less polarized legislature. Open primaries may also succeed in higher salience races, such as a gubernatorial contest, where voters have easier access to information about candidate ideology. Finally, there may be a search for moderation in the general election in cases where two candidates from the same party compete. Future work should address these possibilities. The consequences of primary reform are multifaceted and complex. But in California, simply changing the rules did not appear to change the likely outcomes.