“Parsing Party Polarization in Congress,” James M. Snyder, Jr., Harvard University
AMERICAN & COMPARATIVE POLITICAL BEHAVIOR WORKSHOP
Abstract: A vast literature has documented a growing ideological divide between the parties in the contemporary U.S. Congress. This research almost universally measures this polarization based on estimates from roll-call voting behavior. However, a recent, burgeoning literature has cast doubt on the over-time comparability of such roll-call based measures due to changes in the congressional agenda. We leverage data from candidate surveys that allow us to hold the policy agenda constant across the time period under study, 1996-2006. Our results suggest that polarization is not solely an artifact of an evolving agenda. In contrast to past results, we do not find evidence that members are adopting more extreme positions throughout their tenure in the House when we hold the agenda fixed. Instead, the increasing polarization within the fixed policy agenda is entirely due to replacement: the new members elected to the House during this time period are more extreme than those leaving the House during this period. Consistent with analyses of roll-call based measures, we find that polarization is largely driven by Republican legislators (asymmetric polarization). Our findings suggest that the within-member movement to more extreme positions observed in roll-call voting behavior is the result of a changing agenda, increasing party pressure, or some combination of the two.
Professor Snyder is the Leroy B. Williams Professor of History and Political Science a Harvard University. His primary research and teaching interests are in American politics, with a focus on political representation. He has written on a variety of topics, including elections, campaign finance, legislative behavior and institutions, interest groups, direct democracy, the media, and corruption. He has published more than 100 papers and his articles have appeared in the American Political Science Review, the American Journal of Political Science, the Journal of Politics, the American Economic Review, the Journal of Political Economy, Econometrica, the Quarterly Journal of Economics, and many other other journals and edited volumes. He is co-author of The End of Inequality: One Person, One Vote and the Transformation of American Politics and Primary Elections in the United States. Professor Snyder taught for six years in the Department of Economics at the University of Chicago, and for eighteen years in the Departments of Political Science and Economics at the Massachusetts Institute of Technology. He is a Research Associate at the National Bureau of Economic Research, and a Fellow of the American Academy of Arts and Sciences.
This workshop series is sponsored by the ISPS Center for the Study of American Politics and The Whitney and Betty MacMillan Center for International and Area Studies at Yale with support from the Edward J. and Dorothy Clarke Kempf Fund.