California Journal of Politics and Policy

An experiment conducted by the authors (2014) found that the top-two primary first used in California in June 2012 failed to achieve its sponsors’ goal of helping ideologically moderate candidates win. This paper explores why. A primary reason is that voters are largely ignorant about the ideological orientation of candidates, including the moderates they would choose if proximity voting prevailed. We document this in congressional races, focusing on competitive contests with viable moderate candidates. Our results have a straightforward implication: for the top-two primary to mitigate polarization, moderate congressional candidates would have to inform voters about their moderation to a far greater degree.