Chapter
I. Party Polarization in the 108th Congress (2003–4)
II. Party Polarization since Reconstruction
Party Polarization at the Turn of the Twentieth Century
Party Dynamics in the Middle of the Twentieth Century
Party Polarization in the Post-Reform Congress
III. The Development of Polarization Scores
IV. Polarization Scores within State Delegations
V. The Mechanisms Underlying Polarization
3 Explanations for Party Polarization
I. The Redistricting Explanation
II. The Geographic and Political Sorting of Constituents
III. Extremism of Party Activists
IV. The Institutional Explanation
V. An Integrated Argument of Party Polarization
VI. Adding Complexity to the Integrated Explanation
VII. A Conclusion of Caveats
PART II CONSTITUENCY CHANGE
I. The Ideology of New and Obliterated Districts
II. A Direct Test of Redistricting's Effect on Polarization
III. Redistricting Category Analysis
IV. A Multivariate Assessment of Redistricting
5 The Political and Geographic Sorting of Constituents
I. Ideological Sorting of Voters
II. Sorting into Homogeneous Jurisdictions
Demographic Polarization in Members’ Constituencies
Partisan Outcomes by Congressional District and State
The Partisanship of Members’ Constituencies
Consistency across Races in the Same Election
Consistency Across Elections
III. The Ideology of Members from Strong and Weak States
6 Extremism of Party Activists
I. The Extremism of Convention Delegates
II. The Impact of State Delegations on Senators' Ideologies
A More Sophisticated Analysis
III. The Impact of Party Activists' Extremism on Member Polarization
PART III INSTITUTIONAL CHANGE
7 Connecting Constituency Change to Institutional Change
I. The Growing Ideological Homogeneity of Political Parties
II. The Polarization of Congressional Leaders
III. The Growing Power of More Polarized Leaders
Structuring the Legislative Agenda
The Utility of Using Procedures
The Frequency of Procedural Votes
8 The Interaction in the Legislative Process
I. Categorizing the Votes
II. The Interaction of Constituency Change and Institutional Change
A Reality Check between Data and Theory
Appendix: Verifying the Results with Different Statistical Models
Time Trends in One Regression Model
Separate Estimates for Each Congress
9 The Link between the House and the Senate
I. Comparing Senate Polarization to House Polarization
II. The Effect of House Experience on Senator Ideology
III. The Gingrich Senators
Representation among the Gingrich Senators
10 Procedural Polarization in the U.S. Congress
I. Mandates for Future Research
More than Electoral Changes Have Caused Polarization
Procedural Votes Must Be a Part of the Polarization Conversation
Not All Votes Are the Same
II. Avenues for Future Research
Fleshing Out the Comprehensive Model
Is the Polarization Real?
A Theory of Polarization?