Presidential Coattails and Legislative Fragmentation


  • I am grateful to Nathaniel Beck, William Clark, Jonathan Nagler, Sara Mitchell, Rebecca Morton, David Samuels, Charles Shipan, Sona Nadenichek Golder, three anonymous reviewers, and audiences at Florida State University, the University of Illinois, the University of Iowa, and the University of South Carolina for their helpful comments on this article. The data, codebook, and computer code necessary to replicate the results and figures in this analysis will be made publicly available at on publication. STATA 8 was the statistical package used in this study.

Matt Golder is assistant professor of political science, Florida State University, 531 Bellamy Building, Tallahassee, FL 32306-2230 (


Considerable evidence suggests that legislative fragmentation can negatively affect the survival of democratic presidential regimes. While there is a vast literature examining the determinants of legislative fragmentation, one factor that has traditionally been overlooked is the impact of presidential elections. Do presidential elections increase or decrease legislative fragmentation? Does it matter if presidents are elected by plurality rule or by runoff? Using a new dataset that covers all democratic legislative and presidential elections between 1946 and 2000, I find that presidential coattails can reduce, increase, or have no effect on legislative fragmentation depending on the number of presidential candidates. I also find strong evidence that social heterogeneity increases the number of presidential candidates when runoff systems are employed. Taken together, these results suggest that the widespread adoption of runoffs by newly democratic presidential regimes will likely increase legislative fragmentation, thereby putting their democratic survival at increased risk.