Comparative Political Studies

This article explicates the mechanisms through which presidential elections shape the legislative party system, an issue that has received little attention to date. The authors argue that presidential elections exert their influence through two distinct channels. First, they affect the incentives of candidates, voters, and parties to coordinate within electoral districts. Second and most importantly, they shape the incentives of candidates to coordinate across legislative electoral districts under a common party banner, leading to more aggregated or nationalized party systems when there are few presidential candidates. The authors find support for the relative importance of this cross-district effect using a unique data set of district-level election results from approximately 600 elections in 70 countries.