Senate: Vote on Trade Bill

Below we use Weekly Common Space DW-NOMINATE scores to plot the Senate’s 62-37 vote to pass fast track trade authority for the president.

Senate Republicans split 48-5 in favor of the bill while Senate Democrats voted 14-32 against passage. The Senate Republicans who voted Nay are very ideologically dispersed (the most moderate and conservative Republicans—Senators Susan Collins [R-ME] and Mike Lee [R-UT]—both voted against passage), while the vote more clearly divides Senate Democrats on ideological lines, with Yea votes more likely to come from moderate Democrats such as Senators Heidi Heitkamp [D-ND] and Bill Nelson [D-FL]).

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Ideological Dispersion of the Parties in Congress

A recent New York Times Magazine article examined ideological differences between the progressive and centrist wings of the Democratic Party, using the potential Democratic Senatorial primary race in Maryland between Reps. Donna Edwards and Chris Van Hollen as an example of “the great Democratic crack-up.”

Below we use DW-NOMINATE scores to illustrate the ideological positions of Democrats and Republicans in the current House and Senate (Note: these scores are from a new stand-alone Common Space DW-NOMINATE program that can be run weekly as new roll calls are cast; data available here.)

In the present (114th) Congress, it is clear that Republicans occupy a wider swath of ideological territory than Democrats. It is easy to identify distinct ideological clusters of Republicans, but not for Democrats (a point we make here). The distance between, for instance, Republicans Senators Lisa Murkowski and Ted Cruz dwarfs that between Democratic Senator Elizabeth Warren and former Senator Hillary Clinton. In fact, the distance between Democratic Representatives Donna Edwards and Chris Van Hollen is more comparable with the distances between Senators Lisa Murkowski and John McCain or between Senator McCain and Representative Paul Ryan.

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The images below show trends in the ideological dispersion of the parties in Congress since 1879 by plotting the variance in DW-NOMINATE scores among House and Senate Democrats and Republicans in each Congress. Higher values indicate greater ideological dispersion within the parties in both chambers.

From a peak in the mid-twentieth century (when the Democratic Party was split between its Southern and non-Southern wings), the ideological variance among House and Senate Democrats has steadily declined. Congressional Democrats are now more ideologically unified than at any point since the early 1900s. The ideological variance of Congressional Republicans has been flatter over the last century, but there is some suggestion of a jump in dispersion among Senate Republicans in the 112th Congress (following the 2010 midterm elections).

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Ideology and the Republican Split on the Medicare ‘Doc Fix’ Bill

Below we use Common Space DW-NOMINATE scores to examine the ideological positions of the 33 House Republicans who opposed the Medicare ‘Doc Fix’ bill. These scores represent House members’ positions along the liberal-conservative spectrum, with higher scores indicating greater conservatism.

The 33 House Republicans who voted Nay are among the most conservative members of the House Republican Caucus. Their mean score is 0.640, compared to a mean score of 0.497 for House Republicans as a whole. The group of Republicans who have been an enduring headache for Speaker John Boehner do appear to be very conservative (both in contemporary and historical terms), suggesting that the split between “establishment” and “outsider” congressional Republicans is not just a difference in personal styles, but also rooted in ideological differences.

This image is from a new (nearly) stand-alone Common Space DW-NOMINATE program that can be run weekly as new roll calls are cast.

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