The Lugar Center and Georgetown University’s McCourt School Unveil 2017 Bipartisan Index Rankings for Members of Congress

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Bipartisanship Remains Below Average for 5th Straight Congress, but Rankings Reflect Dramatic Shifts in the Senate

April 24, 2018

WASHINGTON, DC — The Lugar Center, led by former U.S. Senator Richard Lugar, and the McCourt School of Public Policy at Georgetown University today jointly released their new Bipartisan Index (BPI) rankings of members of Congress for 2017.

The BPI is a non-partisan tool that measures the degree to which Senators and Representatives work across party lines on legislation. The latest data reflects significant shifts in bipartisan behavior in the Senate, where Republican scores improved to their highest levels since 2008, while scores of Senate Democrats declined sharply to near record lows.

“Our 2017 Bipartisan Index rankings show that both Houses of Congress remain below average for the fifth straight Congress when measured against the historic baseline,” said Lugar Center President Richard G. Lugar, who served for 36 years as a senator from Indiana. “But in recent years we have seen some overall improvement. Members of Congress, from the most progressive to the most conservative can score well on the Index if they dedicate themselves to seeking bipartisan support for their own legislation and give fair consideration to a variety of legislative initiatives.”

“We are witnessing a tumultuous era in American politics, from the decay of political norms to the rise of ‘fake news.’ For the average consumer of political news, it can be difficult to sort out what’s happening in Congress,” said Michael A. Bailey, interim dean of Georgetown’s McCourt School. “The Bipartisan Index– a non-partisan, evidence-based tool– provides one approach to measuring how often members of Congress reach across the aisle to get something done on behalf of the American people.”

The BPI rankings of Congressional members in 2017, based on bill sponsorship and co-sponsorship data, allow voters to see how willing their senators and representatives have been to work across party lines on legislation.

Based on the new scores, Senator Susan Collins (R, ME) was the most bipartisan senator in 2017 and Representative Collin Peterson (D, MN) was the most bipartisan representative. As in the last Congress, Senator Bernie Sanders (D, VT) had the lowest Bipartisan Index score in the Senate in 2017. Representative Mo Brooks (R, AL) had the lowest BPI score in the House.

Senator Collins continued her dominance of the Bipartisan Index. She has earned the highest Senate ranking in every year since 2013. Her 3.15 score for 2017 is the highest ever recorded on the BPI. The next highest score was 2.72 by Senator Gordon Smith of Oregon in the 110th Congress. She has the third highest lifetime score among all 240 Senators graded since 1993 and the highest lifetime score among senators who have served at least 5 Congresses.

Representative Peterson led the BPI in the House for the first time. His score of 2.09 topped Representative Ileana Ros-Lehtinen’s (R, FL) score of 1.93 for first place.

A BPI score of 0.00 represents the average score for a member over a 20-year statistical baseline. Scores above 0.00 are judged to be bipartisan, those below 0.00 are partisan.

In 2017 the overall BPI score for the Senate was a -.038, slightly better than the -. 072 recorded in 2015-16. The overall House BPI score trended slightly down during 2017, moving from -.206 in 2015-16 to -.231. Because scores for the first year of a Congress can improve in the second year, it is possible that the overall Senate score will move into bipartisan territory during 2018.

Even though overall scores by both Houses in 2017 remained close to scores from the previous Congress, this masked the significant shift of party scores in the Senate. In that chamber, Democrats, who have scored better than Republicans in seven of the twelve full Congresses since 1993, saw their scores decline sharply in 2017 to near record low levels. Meanwhile, as a group, Senate Republicans went from a barely bipartisan score to a creditable .323, the second-highest BPI score the GOP caucus has registered over the past 13 Congresses. The margin between Senate Democrat and Senate Republican scores is the widest recorded in the history of the Bipartisan Index. Index data shows that Senate Republicans are cosponsoring Democratic bills in much higher percentages than is normally the case for the majority party, while Democrats are cosponsoring Republican bills at a lower frequency than is normal for the minority party. The motivations of each member are unique, but the gap in Senate scores between the parties must be seen in the context of relative election vulnerabilities and reactions to the first year of the Trump Administration. (See Lugar Center blog for more discussion)

In the House, Republicans as a group scored slightly better than Democrats (-.14 to -.34).

Thirty-two Republican senators earned positive bipartisan scores, compared to only 14 Senate Democrats. In the House, 89 Republicans earned bipartisan scores, compared to 60 Democrats.

The Senate Republican with the largest improvement over the previous Congress was Sen. Cory Gardner of Colorado (up 1.25 points). The Democratic senator with the biggest improvement in BPI score was Sen. Elizabeth Warren of Massachusetts, with a .45 increase (although she remained below 0.00). The House Republican with the largest improvement was Representative Bruce Westerman (R, AR), up 1.37 points. The House Democrat with the largest improvement was Representative Nydia Velázquez (D, NY), up .85 points (although she remained below 0.00).

The Bipartisan Index measures how often a member of Congress introduces bills that succeed in attracting co-sponsors from members of the other party, and how often they in turn co-sponsor a bill introduced from across the aisle. The Index is based on a formula applied uniformly to all members. No subjective judgments are made about individual members or bills. The Index serves as a critical resource for voters and the media and, its sponsors hope, encourages lawmakers to be more bipartisan when writing or co-sponsoring legislation.

To see current and previous rankings, visit: Our Work

About The Lugar Center:

Under the leadership of former U.S. Senator Richard Lugar, the non-profit Lugar Center is a platform for informed debate and analysis of global issues, including nonproliferation of weapons of mass destruction, global food security, foreign assistance effectiveness and global development, energy security, and enhancing bipartisan governance. http://

About the McCourt School of Public Policy:

Founded in 1996 as the Georgetown Public Policy Institute, the McCourt School of Public Policy at Georgetown University is a top-ranked graduate school located at the center of the policy world in Washington, D.C. Our mission is to give our students the rigorous quantitative and analytic skills needed to design, implement and evaluate smart policies and to conduct policy research and recommend effective solutions on today’s most critical topics.