Bye Bayh, But Why?

Senator Evan Bayh of Indiana announced today that he will not seek re-election this fall. Bayh is a Democrat who has been thought to harbor presidential aspirations. Along those lines, there is some speculation that a weakened President Obama may invite primary challengers in 2012 and that Bayh is positioning himself for a run.

More likely is that 2010, if things continue as they have for the past 12 months, is shaping up to be unfavorable for Democrats in November and that is why the senator, along with several others, is opting out this year.

Another thought has crossed my mind and I wonder if it is a consideration. There seems to be, from what I've read, a growing anti-incumbent sentiment during this election cycle. Could Democrat retirements be an effort to save the seat for the party by removing the incumbent?