Party Polarization and Bipartisan Cosponsorship in the Modern House of Representatives

Perhaps now more than any other time in recent memory, the American political landscape appears to be utterly gripped by polarization. Record delays in Supreme Court nominations and loud, heated battles between the Presidency and Congress, among other features, suggest a deep, troubling political divide that has impacted the production of policy and harmed public trust in government. But is there reason to suspend the assumption that American politics is entirely characterized by polarization? The predominant measures of Congressional polarization are all roll call vote-based measures, which are informative of legislators’ ideologies in the roll call stage, but do not necessarily show stages where legislators are more free to express bipartisan policy positions. Laurel Harbridge has found that while polarization in roll call voting has increased since the 1970’s, bipartisanship at the cosponsorship stage in the House of Representatives has remained robust, experiencing a much less rapid rate of decline than has bipartisanship in roll call voting. This project aims to update Harbridge’s findings for the most recent era of Congress following the emergence of the Tea Party/Freedom Caucus. I employ a number of Harbridge’s methods to analyze bipartisan cosponsorship, including finding overall change in bipartisan cosponsorship, locating some of that change within different policy areas, and examining cosponsorship by cadres of individual legislators. Finally, I seek to resolve a particularly puzzling finding of recent bipartisan cosponsorship by applying theories of localism to the Republican legislators swept into the House during the 2010 Tea Party wave. Doing so should help to offer a more complete picture of House polarization and what that picture might mean for the future of bipartisanship in Congress