Below we use Optimal Classification (OC) in R to plot the House’s 241-180 vote on a $50 billion Hurricane Sandy relief package. The vote was unique in that the majority party was “rolled”, as House Republicans voted 49-179 in opposition to the bill which nonetheless passed with the support of all but one Democrat.
As can be seen in the plot, the 49 Republicans who voted Yea are not only more ideologically moderate (with a mean first dimension OC score of 0.36, compared to 0.51 for those Republicans who voted Nay), but also have higher second dimension scores. On several votes in the 112th Congress, we conjectured that the second dimension has come to represent am establishment vs. anti-establishment divide. In this case, “outsider” House Republicans (with low second dimension scores) were less willing to sacrifice ideological purity on government spending to rescue the party from controversy surrounding the issue.
As a technical note, we are able to plot members of the 113th House so early in the new Congress by combining the roll call voting records of returning members in the 112th House with the 23 roll call votes held so far in the 113th House. Until more votes are compiled for the 81 freshman members, the estimation of their ideal points will remain somewhat imprecise, but by bridging data from the 112th this problem will not be too severe.