Texas Sen. Ted Cruz and fellow presidential candidate Sen. Bernie Sanders are the two most partisan senators according to a ranking released Monday. | AP Photo Sanders, Cruz top list of most partisan senators

The two senators with the most partisan track records also happen to be running for president.

Sens. Bernie Sanders, who is running as a Democrat but is still an independent in Congress, and Ted Cruz (R-Texas) are at the very bottom of the Bipartisan Index of 98 senators released by The Lugar Center and Georgetown University's McCourt School of Public Policy on Monday, taking into account how well members of opposite parties and ideologies work together. Sanders ranks as the most partisan on the list, with a score of -1.95559, while Cruz fared only slightly better, at -1.40999.


Measured primarily through bill sponsorships and co-sponsorships, the index found Sens. Susan Collins (R-Maine) and Joe Donnelly (D-Ind.) as the most cooperative senators in their respective parties. Majority Leader Mitch McConnell (R-Ky.) and Minority Leader Harry Reid (D-Nev.) were excluded from the data.

"If a member is disappointed in his or her score, there is a straightforward way to improve it in future congresses: Put more effort into recruiting bipartisan co-sponsors for your bills and consider co-sponsoring bills introduced by the opposite party," former Sen. Richard Lugar (R-Ind.) wrote. "We hope members will do that and we regard the Bipartisan Index as a way of providing encouragement."

From 1993 to 2014, Sanders ranks as the 11th-most partisan senator, while Cruz is the fourth-most, though the historical data only include the Texas senator's first year in the Senate.