Below we use Optimal Classification (OC) in R to plot the House’s 373-52 vote and the Senate’s 74-19 vote to extending funding for highway, student loan, and National Flood Insurance Program (NFIP) programs.
The bill was the product of extended negotiations between the parties and chambers over recent weeks and months. The most contested portion was over the transportation section, with congressional Republicans wanting to add language allowing for the construction of the Keystone XL pipeline. Eventually, Republicans agreed to drop the issue in return for language that streamlines the environmental permitting process for transportation projects.
Republicans also split on the amount of spending for highway programs. The Chamber of Commerce supported the bill in its final form, as did most congressional Republicans. But more conservative Republicans (52 in the House and 19 in the Senate) broke party ranks to oppose what they saw as excessive spending on transportation projects.
The spatial model captures this split in both chambers quite well. Congressional Republicans who voted “Nay” were more likely to be on the right (conservative) edge of their caucus. The second dimension is also important, as Tea Party Caucus members tend to have lower scores on this dimension and most of the opposition to this bill originated from the Tea Party (e.g, Sens. Mike Lee (R-UT), Rand Paul (R-KY) and Marco Rubio (R-FL) and Reps. Michelle Bachmann (R-MN) and Ron Paul (R-TX) all voted “Nay.”)
Note: The plot for the House vote shows only 372 “Yea” votes, when there were actually 373. This is because newly-elected Rep. Ron Barber (D-AZ), who replaced former Rep. Gabrielle Giffords, has not cast enough votes to be included in our scaling.