More a Molehill than a Mountain: The Effects of the Blanket Primary on Elected Officials’ Behavior from California

Scholars, politicians, parties, and the U.S. Supreme Court argue that restricting the set of eligible voters for a primary election affects the nature of representation voters receive from elected officials. Evidence supporting this argument is elusive because the same elected officials are often responsible for determining the type of primary election used. Using a quasi-natural experiment resulting from a 1996 constitutional referendum in California, we examine whether expanding the eligible primary electorate from only registered partisans to any registered voter affects who is elected and the positions elected representatives take. We show that the blanket primary appears to favor the election of more moderate representatives and that incumbents take more moderate positions in the U.S. House of Representatives and California Assembly. This is true only in less partisan districts, and there are no effects in districts dominated by a single party. These differential effects suggest that concerns about representatives becoming increasingly polarized in legislatures are not likely remedied by simply expanding the set of voters eligible to participate in primary elections.1