Garrett Vande Kamp Texas A&M University garrettvandekamp@ tamu. edu CPG theory offers a convincing explanation of party polarization in Congress. This paper looks at what might be called the “pre-condition” necessary to produce homogeneous party caucuses—preferences in partisan reelection constituencies realign to become more similar across the nation. Analysis of voters’ ideology in red, purple, and blue districts from the 1970s to the 2000s provides evidence that partisan voters’ issue preferences have realigned in ways consistent with CPG theory. All indicators—correlation between party and ideology, divergence of intra-party and convergence of intra-party means, overlap, and skewness—show evidence of increasing homogeneity in all types of district. Change occurred primarily among Democrats. Democratic voters’ preferences were quite diverse in the 1970s, but by the 2000s the distributions were skewed right with pluralities in the liberal mode in all types of districts. Republican voters’ preferences have been consistently homogeneous—the distributions have been skewed left with large majorities in the conservative mode in all types of districts since the 1970s.
We acknowledge support from the Department of Political Science at Texas A&M University. We are grateful for helpful suggestions from Dan Wood, to Matt Levendusky for sharing his computer code, to Gary Jacobson for sharing data on the presidential vote in congressional districts, and to Rich Fleisher for his contributions to earlier iterations of this study.
Bond, J. R., & Vande Kamp, G. (2016). The Party Polarization Process in Congress: A Look at the Pre-condition in Conditional Party Government.
