Joe Lieberman (R?-CT)

I hadn't really thought about this possibility:

Sen. Joe Lieberman (I-Conn.) could have the power to decide who controls the Senate after the midterm elections.

Polling suggests Republicans could pick up as many as nine seats this fall, making a 50-50 split between the two parties a distinct possibility.

A nine-seat gain for the GOP would give Democrats the slimmest possible majority: a caucus of 50, made up of 48 Democrats and two independents, Lieberman and Sen. Bernie Sanders (Vt.). Vice President Joe Biden would become the crucial tie-breaking vote in the Democrats' favor.

But that one-vote majority would hinge on Lieberman continuing to caucus with the Democrats. Under that scenario, the Democratic Party's love/hate relationship with Lieberman could reach a critical juncture.

Lieberman is facing a tough reelection fight in 2012 and could be tempted to caucus with the Republicans — or switch parties outright — during the next Congress.

The senator has never definitively ruled out becoming a Republican, but has instead stuck to declarations of independence. Asked this week about the senator's political affiliation, spokesman Marshall Wittmann said: “Sen. Lieberman is happy where he is in the Senate and has no other plans.”

I don't think Lieberman will switch parties or caucus with the GOP. With the exception of the war he's just too far from most GOP positions. And if he did switch parties I can guarantee you the GOP would run a much more conservative primary challenger against him and he'd be in the same situation he was in during his last election when he ended up leaving his party and running as an independent.

He'll stay an independent and will probably continue to caucus with the Dems.  And Joe Biden will be breaking a lot of ties.