U.S. Senate Social Graph, 1991 - Present

• Each dot represents a U.S. senator

• Senators become connected if they vote together 65% or more during a session

• Visualization technique reveals affinity clusters within and across the parties over time

102nd Session

Daniel Inouye (HI)

Quintin Burdick (ND)

Al Gore (TN)

Arlen Specter (PA)

Bob Packwood (OR)

William Cohen (ME)Mark Hatfield (OR)

Jesse Helms

(NC)

January 3, 1991, to January 3, 1993First Gulf war. Dems hold majority. Fairly weak voting blocks with considerable spread within and across parties.

Howell Heflin (AL)

Richard Shelby (AL)

DemocratRepublicanindependentUnable to identify

103rd Session

Jim Jeffords

Richard Shelby

Mark Hatfield

Arlen Specter

John Chaffee

Note how Dems split into 2 distinct buttight blocks. Repubs are more diffuse.

January 3, 1993 to January 3, 1995

104th Session1994 Republican Revolution. Repubs gain majority of both houses for first time since 1950s.No cross-party connections. Both parties form solid blocks.

Jim Jeffords (VT)

Arlen Specter (PA)

Howell Heflin (AL)

January 3, 1995 to January 3, 1997

105th Session

Jim Jeffords (VT)

Arlen Specter (PA)

January 3, 1997 to January 3, 1999

House impeaches Clinton. Dem voting block in Senate reemerges.

106th Session

Lincoln Chaffee (RI)

Jim Jeffords (VT), becomes independent mid-term

Clinton impeachment trial early in this session. Note how Dems generally maintain unity, but Repubs. fracture into 2 groups. Session ends with Bush v. Gore.

Arlen Specter (PA)

John McCain (AZ)

January 3, 1999 to January 3, 2001

107th SessionJanuary 3, 2001 to January 3, 2003

September 11 attacks. Iraq war resolution. Strong party unity with slight fracture in Dem “liberal” wing. Movement in the middle, with Liberal Repubs moving towards Dems, and conservative Dems move toward Repubs..

Ben Nelson (NE)

JohnBreaux (LA)

LincolnChaffee (RI)

Zell Miller (GA)

SusanCollins

(ME)

OlympiaSnow (ME)

JesseeHelms (NC)

108th SessionJanuary 3, 2003 to January 3, 2005

Ben Nelson (NE)

NormColeman (MN)

SusanCollins (ME)

OlympiaSnowe (ME)

ArlenSpecter (PA)

Dems still have slight fracture. Repubs maintain a slight majority with asolid block. However, slight split with Moderate Repubs like Snow, Collins, and Coleman.

Zell Miller (GA), switches parties mid-term

109th Session

Ben Nelson

(NE)

LincolnChaffee (RI)

Olympia Snowe

(ME)

Susan Collins (ME)

Arlen Specter

(PA)

BarackObama

Hurricane Katrina, Tom Delay investigation,Terri Schaivo, Abramoff scandal. Dems break into 3 groups, with moderates breaking towards themore liberal members.

January 3, 2005 to January 3, 2007

110th SessionJanuary 3, 2007 to January 3, 2009

Hillary Clinton (NY)

JoeBiden

Sam Brownback (KS)

Arlen Specter (PA)

Gordon Smith (OR)

Susan Collins (ME)

Olympia Snowe (ME)

Ben Nelson (NE)

NormColeman

(MN)

Conservative Repubs split into identifiablevoting block. Split in Dems is reduced. Democrats increased their congressional majorities at mid-termand Senator Barack Obama was elected President.

111th SessionJanuary 3, 2007 to present

With Specter party switch, Dems have a 60 voteMajority, as well as continued support from moderateRepublicans. However, there appears to be a large splitin the core Dem blocks. Looks as though a new groupof Repubs could be splitting off from the core.

Ben Nelson (NE)

OlympiaSnowe (ME)

SusanCollins (ME)

ArlenSpecter (PA)

GeorgeVoinovich (OH)

Judd Gregg (NH)

•Murkowski (AK)•Lugar (IN)•Alexander (TN)

•Bond (MO)

For more info…

• To see how the graphs were generated and get further explanation, see:

http://broadcast.oreilly.com/2009/05/us-senato-social-graph-1991--.html

Or

http://bitly.com/OujpP