In an earlier post, I talked about the asymmetrical polarization of US congress, and how DW-NOMINATE is used to quantify it. In this post, I’m going to discuss more technical details. I’ll explain why I was initially skeptical, and why I came to accept the argument.
But before I get into the math, I should first emphasize that there are many arguments demonstrating that the US congress has become more polarized, and that the Republican party in particular is more extreme. I think those arguments stand on their own, with or without using any evidence from DW-NOMINATE. You can read some of those arguments here, or watch the Vox video I linked last time. It’s not just liberals who are saying this–one of the big proponents of asymmetrical polarization theory is Norman Ornstein, member of the conservative think tank American Enterprise Institute;