Abstract

The Top Two primary is one of the most interesting and closely-watched political reforms in the United States in recent years.  This radically open primary system removes much of the formal role for parties in the primary election and even allows for two candidates of the same party to face each other in the fall. An important goal of this reform has been to elect more moderate candidates to public office. In this paper, we leverage the adoption of the Top Two in California and Washington to explore the reform’s effects on legislator behavior. We find an inconsistent effect since the reform was adopted in these two states. The evidence of post-reform moderation is stronger in California than in Washington, but a substantial portion of this stronger effect stems from an equally radical contemporaneous policy change—district lines drawn by an independent redistricting commission. The results validate some claims made by reformers, but question others.