It Takes an Outsider: Extralegislative Organization and Partisanship in the California Assembly, 1849–2006


  • I am grateful to Jeff Lewis, Mat McCubbins, Keith Poole, Ken Schultz, and John Zaller for their assistance during the preparation stage of this manuscript. I also wish to thank John Aldrich, John Coleman, Greg Koger, Hans Noel, Tom Knecht, Jing Sun, and Nancy Wadsworth for their helpful feedback. Much of the funding for this data collection project comes from the National Science Foundation under Grant No. 0214514. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.

Seth E. Masket is assistant professor of political science, University of Denver, 471 Sturm Hall, 2000 East Asbury Avenue, Denver, CO 80208 (


Why are American politicians “single-minded seekers of reelection” in some decades and fierce ideological warriors in others? This article argues that the key to understanding the behavior of members inside a legislative chamber is to follow the actions of key figures outside the chamber. These outsiders—activists, interest groups, and party bosses—use their control over party nominations, conditioned on institutional rules, to ensure ideological behavior among officeholders. To understand how vital these outsiders are to legislative partisanship, this article takes advantage of a particular natural experiment: the state of California's experience with cross-filing (1914–59), under which institutional rules prevented outsiders from influencing party nominations. Under cross-filing, legislative partisanship collapsed, demonstrating that incumbents tend to prefer nonpartisanship or fake partisanship to actual ideological combat. Partisanship quickly returned once these outsiders could again dominate nominations. Several other historical examples reveal extralegislative actors exerting considerably greater influence over members' voting behavior than intralegislative party institutions did. These results suggest that candidates and legislators are the agents of activists and others who coordinate at the community level to control party nominations.