In an op-ed in Tuesday’s New York Times, Sen. Charles E. Schumer of New York called for an end to partisan primaries and the implementation of a top-two system nationwide, asserting that such a change would lessen the historic level of polarization between Democrats and Republicans. According to Schumer, a Democrat, all we need to do to get more moderates elected is use the system put in place in California. There, all candidates, regardless of party identification, face off against one another in the primary. The two top vote-getters advance to the general election.
Here’s the problem with Schumer’s argument: There isn’t much evidence to support it. Let’s look at California, which adopted the top-two primary via a 2010 constitutional amendment, as an example. Schumer said the top-two system in California “has had a moderating influence on both parties and a salutary effect on the political system and its ability to govern.” But any shift in the state’s politics can’t be ascribed to the top-two system — at least not yet. A coin landing on heads two times in a row isn’t evidence that the coin is weighted.
Moreover, it doesn’t look like there has been a trend toward moderation in California. The state’s legislature has been quite as polarized as anywhere else. Political scientists Douglas Ahler, Jack Citrin and Gabriel Lenz of the University of California, Berkeley, studied the 2012 top-two primary results and found that moderate candidates didn’t do any better than they would have in a closed, intra-party primary vote. These results held for the U.S. House and state Senate races.
Ahler, Citrin and Lenz found that voters didn’t differentiate between extreme and moderate candidates. Voters may be willing to cast votes for moderate candidates, but they didn’t know who those candidates were. Instead, they relied on a candidate’s party identification. And because most voters (including independents) lean toward one party or another, their votes are reliably partisan.
But even if moderates didn’t fare that well, couldn’t it be that the top-two primary forced extreme candidates to become more moderate? Probably not. Political scientists Thad Kousser of the University of California, San Diego, Justin Phillips of Columbia University and Boris Shor of the University of Chicago found that, if anything, California’s elected lawmakers took even more extreme positions after 2012.
The pattern appears to be holding in 2014.
That’s not to say California’s top-two system won’t eventually have a moderating effect (although Washington state, which has had a top-two system since 2008, hasn’t seen a move to the middle). We’ll have to wait for a few more election cycles to be more confident one way or the other. But right now, a top-two primary doesn’t seem to alleviate polarization.