The Senate's Home-State Twins—PICTURES

In Colorado, Democratic Sens. Michael Bennet, center, and Mark Udall, left, had a voting score differential of 3.2 points in the 2011 vote ratings. (ED ANDRIESKI/AP)

Republican Sens. Mike Crapo, left, and James Risch, right, of Idaho had a voting score differential of only 2.1 points. (HARRY HAMBURG/AP)

With the impending retirement of Olympia Snowe, left, her cheerful senatorial partnership with Susan Collins, right, will not see the next Congress.  The two Maine Republicans had a score differential of 1.3. (HARRY HAMBURG/AP)

Democratic Sens. Mark Warner, left, and Jim Webb, right, of Virginia had a score differential of 4.7. (GARY C. KNAPP/AP)

Democratic Sens. Ben Cardin, left, and Barbara Mikulski, right, of Maryland, appear to be the most jovial pairing of senatorial twins, with a differential of 2.2.  (CHRIS GARDNER/AP)

Democratic Sens. Max Baucus, right, and Jon Tester, left, of Montana have a 4.9-point differential between their voting scores. (REED SAXON/AP)

Jack Reed, right, and Sheldon Whitehouse, center, both Democrats from Rhode Island, have identical voting scores for 2011, placing them at the top of the Senate Twins list. (JOE GIBLIN/AP)

Sens. Johnny Isakson, left, and Saxby Chambliss, right, both Republicans from Georgia, only have a 2.5 voting score differential for 2011. (JOHN BAZEMORE/AP)

The two senators from Kansas, Pat Roberts, center, and Jerry Moran, left, rank second on the list with only a 0.8 differential. (JOHN HANNA/AP)

Republican senatorial twins John McCain, right, and Jon Kyl, left, of Arizona share a laugh and a nearly identical 2011 voting record.  They have a differential of 1.4. (J. SCOTT APPLEWHITE/AP)