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Agency, Monitoring, and Electoral Institutions: The 17th Amendment and Representation in the Senate (WP-06-04)

Sean Gailmard and Jeffery A. Jenkins

Delegation of decision-making authority to agents with different preferences and better information than their principals is ubiquitous in politics, and political representation is no exception. A prominent change in a political agency relationship, at least in formal terms, occurred when the 17th Amendment to the Constitution established direct election of U.S. senators as of 1914. What effect did this institutional change have on the representation of states by their senators?

The authors argue that before the 17th Amendment, the state population relied on an intermediary, the state legislature, to control its U.S. senators. This intermediary was a sophisticated monitor of the behavior of senators, but itself not a perfect agent of the populace. After the 17th Amendment, the state populace gained more direct control over its U.S. senators, but sacrificed expert monitoring of their behavior. If this view is correct, senators after the 17th Amendment should better reflect the ideology of their home states’ populace, but also exhibit greater variability relative to other members of their state’s delegation.

The authors show that these expectations are borne out empirically. First, U.S. senators from moderate states exhibit less extreme roll-call behavior after the 17th Amendment. Second, differences in roll-call records for senators from the same state are greater after the 17th Amendment. The authors argue that this change is one factor that has made the Senate a less polarized body since passage of the 17th Amendment.

Sean Gailmard, Department of Political Science, Northwestern University

Jeffery A. Jenkins, Department of Political Science, Northwestern University

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