Controlling the Agenda

Owen Rice has a series of cool charts that show optimal classification location of members of congress and “cutting lines” on various votes. The way it works is first you locate members, based on their votes, into a two-dimensional ideological space. Then on any given vote you can create a “cutting line” across the ideological space that does the best possible job of correcting sorting members into yeas and nays. That helps you get a sense of the underlying dynamic of the issue.

Here’s an example of a vote that broke down on pure party lines:

Kevin Drum wants to know why the optimal classification comes out this way:

Actually, though, I think I’m more interested in the placement of senators themselves. Democrats are almost all bunched into a single grouping, with only four outliers. Republicans, by contrast, are spread through considerably more space on both the economic and social dimensions. That doesn’t seem intuitively right to me, but it strikes me as more complimentary toward Republicans than Democrats. So tell me again why they want to defund pointy-headed political scientists?

It’s not intuitively right. What I think it is is an illustration of the importance of setting the agenda. The Democratic leadership has only brought to a vote bills that unite the overwhelming majority of Democrats. Consequently, a visualization based on votes of the 111th Senate shows the Democrats as enormously bunched-together. If you look at the House where Nancy Pelosi doesn’t need a unanimous caucus to pass bills, you see that Democrats and Republicans are about equally dispersed. If Republicans were to capture the House and pick up some Senate seats in 2010, then legislation would more often be focused on issues that split the party caucuses (education, immigration) and the visualizations would look different.