Study Finds Sanders, Cruz to Be the Senate’s Most Partisan Members
Policy + Politics

Study Finds Sanders, Cruz to Be the Senate’s Most Partisan Members

Surprise! Republicans are more bipartisan than Democrats


An annual survey of bipartisanship in the U.S. Congress was released yesterday, and there is both good news and bad news. The good news is that the overall level of bipartisanship in the first session of the 114th Congress ticked up a little bit from the abysmal showing of its two predecessors. The bad news is that the two most partisan members of the Senate are currently contenders for their parties’ respective presidential nominations.

Vermont Sen. Bernie Sanders, currently challenging former Secretary of State Hillary Clinton for the Democratic presidential nomination, came in dead last in the Index’s ranking of U.S. senators. Next behind him (though far closer to the mainstream than Sanders) was Texas Sen. Ted Cruz, currently struggling to knock billionaire Donald Trump out of the lead for the GOP nomination.

Related: Ted Cruz Is Now the Guardian of the GOP’s Legacy?

The Index analyzed more than 20 years of data and determined that the two most recent Congresses--the 112th and 113th--were the most partisan in recent history. The data shows the first session of the 114th marks the second year in which bipartisan sponsorship of bills has increased.

Another interesting nugget from the study is that despite the Republican Party’s general reputation for rabid partisanship, the Bipartisan Index finds that the lawmakers ranking among the most bipartisan in both the House and Senate are overwhelmingly Republican.

The Bipartisan Index is a joint project of Georgetown University’s McCourt School of Public Policy and of the Lugar Center, a Washington, DC-based think tank founded by Richard Lugar, the former Republican senator from Indiana.

The Index is a measure of how often a member of Congress co-sponsors a bill proposed by a member of the opposite party, and of how often each member’s own bills are themselves co-sponsored by members of the other party.

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“We gravitated toward bill sponsorships and co-sponsorships for two reasons,” Lugar wrote in an introduction to the study. “First, they allowed us to construct a highly objective measure of partisan and bipartisan behavior. Second, sponsorship and co-sponsorship behavior is especially revealing of partisan tendencies. Members’ voting decisions are often contextual and can be influenced by parliamentary circumstances. Sponsorships and co-sponsorships, in contrast, exist as very carefully considered declarations of where a legislator stands on an issue.”

The Index assigns lawmakers a score based on their sponsorship activity on a scale where a score of 0.0 indicates perfect alignment with the average over the last 20 years. A positive score indicates a lawmaker is more bipartisan than that average, a negative score the opposite.

Sanders and Cruz, for reference, had scores of -1.96 and -1.41, respectively. At the top of the chart for the Senate was Maine’s Susan Collins, a Republican, with a score of 2.3. Democrat Joe Donnelly, of Indiana, was second at 1.83. In the Senate, the top 10 ‘most bipartisan’ lawmakers included seven Republicans and three Democrats. And the ten ‘least bipartisan’ members included six Democrats and four Republicans.

In the House, the highest-ranking lawmakers broke down along similar party lines. Seven of the top 10 were Republicans, with New York Rep. Peter King at the top of the heap. However, Republicans also dominated the bottom ten, taking eight of the 10 lowest scores for bipartisanship.