Get access

Agency Problems, the 17th Amendment, and Representation in the Senate


  • A previous version was presented at American University, Caltech, Duke, Florida State, George Mason, Harvard/MIT, Notre Dame, Penn State, SUNY-Buffalo, Texas A&M, the University of Chicago, the University of Iowa, the University of Virginia, William & Mary, the 2005 meeting of the Midwest Political Science Association, and the 2006 NBER Development of the American Economy Summer Institute. We thank the audiences and Scott Ainsworth, Chris Berry, Fred Boehmke, Doug Dion, Erik Engstom, David Epstein, Jeff Grynaviski, Sam Kernell, Jeff Milyo, Roger Myerson, John Patty, Dave Primo, Wendy Schiller, Chuck Shipan, and Craig Volden for helpful comments.

Sean Gailmard is Assistant Professor, Charles and Louise Travers Department of Political Science, University of California, Berkeley, 210 Barrows Hall, Berkeley, CA 94720 ( Jeffery A. Jenkins is Associate Professor, Woodrow Wilson Department of Politics, University of Virginia, Charlottesville, VA 22904 (


A prominent change in American electoral institutions occurred when the 17th Amendment to the Constitution established direct election of U.S. Senators as of 1914. How did this change the political agency relationship between the mass electorate and U.S. Senators? We develop theoretical expectations about the representational effects of direct election by a relatively inexpert mass electorate and indirect election by a relatively expert political intermediary, based on principal-agent theory. The chief predictions are that the representative will be more responsive to the mass electorate under direct election, but will also have more discretion to pursue his or her own ends. We use the 17th Amendment as a quasi-experiment to test the predictions of the theory. Statistical models show strong support for both predictions. Moreover, the 17th Amendment is not associated with similar changes in the U.S. House of Representatives—as expected, since the amendment did not change House electoral institutions.