But worrying about majorities and whip counts is largely a partisan task, and hardly the concern of moderates like Snowe, who have grown weary of the bickering on Capitol Hill. For that reason, it's not so surprising that Snowe didn't go out of her way to give Cornyn and McConnell a heads up.
"Unfortunately, I do not realistically expect the partisanship of recent years in the Senate to change over the short term," Snowe said on Tuesday.
Awfully similar to Bayh's words from two years ago.
"There is too much partisanship and not enough progress -- too much narrow ideology and not enough practical problem-solving. Even at a time of enormous challenge, the peoples' business is not being done," he said at the time.
As Reid Wilson noted this morning
, Snowe was the second-most liberal Republican in National Journal
's annual vote ratings. Sen. Ben Nelson
, D-Neb., the most conservative Democrat in the upper chamber, and Sen. Joe Lieberman
, I-Conn., the third-most conservative senator to caucus with Democrats, are also stepping aside.
There's a certain degree of irony in the fact that majorities are won and lost in the middle, where moderates like Snowe and Nelson, who have bucked their respective parties many times, reside. It's often the candidates least interested in their party's grasp on power that prove to be most vital to preserving it.
The exits of moderates like Snowe and Bayh and the reduction of the middle in both chambers only trigger more polarized environments. Bayh, for example, was replaced by Republican Dan Coats
, who ranks as the 25th most conservative senator, according to NJ's 2011 vote ratings.