So Neal Beck asks:
so, post last night, do you have and can you send a picture of the current senate lr positions – am curious as to what happens when one crosses out chafee and makes some guesses about tester and webb.
I grabbed the roll call data from Jeff Lewis’ web site using the nifty readKH() function in our pscl R package, and then ran a one-dimensional ideal point model (a la Clinton, Jackman, and Rivers APSR 2004), also implemented in the pscl R package. I then plot the ideal point estimates against Bush vote share in the senators’ respective states in 2004, producing the scatterplot shown below. Each point corresponds to a senator (red for Republicans, blue for Democrats, with senators running for re-election given a heavier shading), with Bush vote on the horizontal axis, and the voting score on the vertical axis (higher is more conservative, lower is more liberal). The gray line is a regression fit, not to be taken too seriously (read on…).
The biggest thing that jumps out at you when do plots like these is the separation by party (there is virtually no overlap between the red and blue dots), but reasonable tracking between a state’s political orientation (at least, in this case, as reflected by Bush 2004 vote share) and legislative behavior.
Anyway, in response to Neal’s query, I’ve highlighted the six Republican senators who have (or seem likely) to lose their seats; they are numbered 1 through 6, the other Republican senators who were re-elected are numbered 7 through 14. Chafee (RI), Santorum (PA) and Allen (VA) seem to be the only Republican losers who are obvious candidates for a “out of step with their state” kind of story (a la Canes-Wrone, Brady and Cogan APSR 2002), lying relatively distant from the regression line. DeWine (OH) seems to have been caught in what was a wipeout for Republicans in OH; neither Talent (MO) nor Burns (MT) appear to have been particularly “out of step” (Burns is projected to lose by a whisker). And keep in mind that we’ve got Republican senators — some perhaps just as apparently “out of step” as Santorum etc — who did not lose their seats (e.g., Kyl, AZ).
It is interesting to speculate on shape of the new Senate (the 110th). Chafee goes, replaced by a Democrat, leaving the Maine women (Snowe and Collins) as the most moderate Republicans. We’ll see just how liberal or moderate the new Democrats are; given their states and the narrow margins with which they are projected to win, it is tough to imagine Webb (D-VA) or Tester (D-MT) being particularly liberal, perhaps more like the relatively conservative Democrats from the plains (Nelson, NE; Conrad and Dorgan from ND) or the other MT senator (Baucus).
A similar exercise for the House would also be interesting (Keith, Jeff…???)
