So get this: Susan Collins (RINO-Maine), is currently chairwoman of the Senate Committee on Homeland Security. That just so happens to be the post Joe Lieberman is in line for.
If I'm Harry Reid, looking to firm up my majority with an anti-ANWR drilling, anti-defense of marriage amendment, generally pro-choice moderate, it's hard to imagine a better candidate than Collins.
She keeps her chair, gets credit for finally implementing the 9/11 Commission recommendation, and will have four years for her constitutents to get over her party flip.
Joe Lieberman gets pushed aside to something less consequential, and the Democrats would enjoy a 52 vote caucus.