The Jeffords Switch

Changing Majority Status and Causal Processes in the U.S. Senate
Chris Den Hartog and Nathan W. Monroe
A creative and nuanced approach that takes advantage of an organic shift in Senate power to uncover how Senate power actually works.


Senator Jim Jeffords left the Republican Party in May 2001 and became an independent. Because he agreed to vote with the Democrats on organizational votes, this gave that party a 51–49 majority in the Senate.
Using the “Jeffords switch,” Chris Den Hartog and Nathan W. Monroe examine how power is shared and transferred in the Senate, as well as whether Democratic bills became more successful after the switch. They also use the data after the switch, when the Republican Party still held a majority on many Democratic Party-led committees, to examine the power of the committee chairs to influence decisions. While the authors find that the majority party does influence Senate decisions, Den Hartog and Monroe are more interested in exploring the method and limits of the majority party to achieve its goals.

“A worthy professional contribution to the literature on the Senate, this book advances the debate on how parties make a difference in the Senate, and Congress more generally, with important new perspectives and empirical findings. Den Hartog and Monroe’s inclusion of case study and elite interview material provide richness and welcome nuance to the analysis.”
—Bruce Oppenheimer, Vanderbilt University
“A splendid example of scholars taking advantage of a natural quasi-experiment in a creative way, combining quantitative, qualitative, and case-study materials to weave a nuanced and compelling narrative. I think it will be a visible and well-cited contribution to the literatures on Congress and quasi-experimental design.”
—Walter Stone, University of California, Davis
“This creative new book on the Jeffords Switch offers a nuanced examination of the role of majority parties in structuring outcomes in the U.S. Senate, since the authors have a chance to “hold everything else constant” in their analysis within the same Congress.”
—Jamie L. Carson, University of Georgia

Chris Den Hartog is Professor of Political Science at California Polytechnic State University.
Nathan W. Monroe is Professor of Political Science and Tony Coelho Endowed Chair of Public Policy at the University of California, Merced.

Product Details

  • 6 x 9.
  • 232pp.
  • 10 charts, 26 tables.
Available for sale worldwide

  • Hardcover
  • 2019
  • Available
  • 978-0-472-13142-6

Add to Cart
  • $75.00 U.S.

Related Products



  • Congress; Senate; Parties; Congressional theories; Agenda setting; Agenda power; James Jeffords; Jeffords switch; Mixed methods; Quasi-experiment; Natural experiment; Casual process tracing; Party switch; Scientific method; Power sharing agreement; Senate scheduling; Motion to proceed; Unanimous Consent Agreements (UCAs); Patients Bill of Rights; No Child Left Behind; Bush tax cuts; McCain-Feingold