The Senate:

59 Democrats, 41 Republicans, and an average obstruction rate of 25.9%.

The Whole List

Name Obstruction Rate
Jim DeMint (R-SC) 90.7%
Jim Bunning (R-KY) 89.5%
Tom Coburn (R-OK) 82.2%
Jeff Sessions (R-AL) 82.2%
Jim Inhofe (R-OK) 80.0%
Sam Brownback (R-KS) 77.3%
John Ensign (R-NV) 76.2%
Jon Kyl (R-AZ) 75.6%
John Cornyn (R-TX) 73.2%
Pat Roberts (R-KS) 72.5%
David Vitter (R-LA) 72.5%
Mitch McConnell (R-KY) 71.7%
John McCain (R-AZ) 70.5%
Richard Shelby (R-AL) 70.2%
Mike Crapo (R-ID) 69.6%
Jim Risch (R-ID) 69.6%
Richard Burr (R-NC) 69.0%
Mike Enzi (R-WY) 68.9%
Chuck Grassley (R-IA) 68.1%
Johnny Isakson (R-GA) 66.7%
John Barrasso (R-WY) 66.0%
George LeMieux (R-FL) 65.2%
Bob Corker (R-TN) 64.4%
Mike Johanns (R-NE) 64.4%
John Thune (R-SD) 63.0%
Kay Hutchison (R-TX) 61.8%
C. Saxby Chambliss (R-GA) 61.4%
Roger Wicker (R-MS) 60.9%
Lindsey Graham (R-SC) 60.5%
Kit Bond (R-MO) 57.1%
Bob Bennett (R-UT) 54.8%
Judd Gregg (R-NH) 53.8%
Lamar Alexander (R-TN) 53.3%
Orrin Hatch (R-UT) 51.2%
Thad Cochran (R-MS) 46.7%
Scott Brown (R-MA) 40.0%
George Voinovich (R-OH) 38.1%
Richard Lugar (R-IN) 37.8%
Lisa Murkowski (R-AK) 35.6%
Susan Collins (R-ME) 25.5%
Olympia Snowe (R-ME) 23.4%
Russell Feingold (D-WI) 14.9%
Claire McCaskill (D-MO) 6.8%
Evan Bayh (D-IN) 6.4%
Kay Hagan (D-NC) 6.4%
Ben Nelson (D-NE) 6.4%
Harry Reid (D-NV) 6.4%
Robert Byrd (D-WV) 6.1%
Arlen Specter (D-PA) 4.4%
Blanche Lincoln (D-AR) 4.3%
Jim Webb (D-VA) 4.3%
Mark Begich (D-AK) 2.4%
Joseph Lieberman (I-CT) 2.2%
Mark Pryor (D-AR) 2.2%
Ron Wyden (D-OR) 2.2%
Kent Conrad (D-ND) 2.2%
Bill Nelson (D-FL) 2.2%
Bernie Sanders (I-VT) 2.2%
Jon Tester (D-MT) 2.2%
Mark Warner (D-VA) 2.2%
Max Baucus (D-MT) 2.1%
Maria Cantwell (D-WA) 2.1%
Byron Dorgan (D-ND) 2.1%
Herb Kohl (D-WI) 2.1%
Jeff Merkley (D-OR) 2.1%
Daniel Akaka (D-HI) 0.0%
Michael Bennet (D-CO) 0.0%
Jeff Bingaman (D-NM) 0.0%
Barbara Boxer (D-CA) 0.0%
Sherrod Brown (D-OH) 0.0%
Roland Burris (D-IL) 0.0%
Ben Cardin (D-MD) 0.0%
Tom Carper (D-DE) 0.0%
Bob Casey (D-PA) 0.0%
Chris Dodd (D-CT) 0.0%
Dick Durbin (D-IL) 0.0%
Dianne Feinstein (D-CA) 0.0%
Al Franken (D-MN) 0.0%
Kirsten Gillibrand (D-NY) 0.0%
Tom Harkin (D-IA) 0.0%
Daniel Inouye (D-HI) 0.0%
Tim Johnson (D-SD) 0.0%
Ted Kaufman (D-DE) 0.0%
John Kerry (D-MA) 0.0%
Amy Klobuchar (D-MN) 0.0%
Mary Landrieu (D-LA) 0.0%
Frank Lautenberg (D-NJ) 0.0%
Patrick Leahy (D-VT) 0.0%
Carl Levin (D-MI) 0.0%
Robert Menendez (D-NJ) 0.0%
Barbara Mikulski (D-MD) 0.0%
Patty Murray (D-WA) 0.0%
Jack Reed (D-RI) 0.0%
Jay Rockefeller (D-WV) 0.0%
Chuck Schumer (D-NY) 0.0%
Jeanne Shaheen (D-NH) 0.0%
Debbie Stabenow (D-MI) 0.0%
Mark Udall (D-CO) 0.0%
Tom Udall (D-NM) 0.0%
Sheldon Whitehouse (D-RI) 0.0%

Least Obstructionist Republicans

Members of the minority party that have voted for cloture most often.

Olympia Snowe (R-ME) 23.4%
Susan Collins (R-ME) 25.5%
Lisa Murkowski (R-AK) 35.6%
Richard Lugar (R-IN) 37.8%
George Voinovich (R-OH) 38.1%

Most Obstructionist Democrats

Members of the majority party that have voted against cloture most often.

Russell Feingold (D-WI) 14.9%
Claire McCaskill (D-MO) 6.8%
Ben Nelson (D-NE) 6.4%
Evan Bayh (D-IN) 6.4%
Harry Reid (D-NV) 6.4%

Most Vulnerable in 2010

Incumbents that face difficult re-election campaigns, based on FiveThirtyEight's rankings.

Republicans

Jim Bunning (R-KY) 89.5%
Richard Burr (R-NC) 69.0%
David Vitter (R-LA) 72.5%
Chuck Grassley (R-IA) 68.1%
Tom Coburn (R-OK) 82.2%

Democrats

Chris Dodd (D-CT) 0.0%
Michael Bennet (D-CO) 0.0%
Roland Burris (D-IL) 0.0%
Harry Reid (D-NV) 6.4%
Arlen Specter (D-PA) 4.4%