A Daily Kos/Research 2000 poll from last week had given Bayh, a two-term senator and former two-term governor, leads of 20 and 16 points respectively over two of Republican challengers, former Sen. Dan Coats and former Rep. John Hostettler.
So what next? Bayh's state has historically been friendly to Republicans, but in 2008 ended up voting for Barack Obama by a margin of about one percent -- after having previously voted for George W. Bush by a 21-point margin 2004. Republicans currently control all statewide offices and one chamber of the state legislature, as well as the mayor's office in Indianapolis. On the other hand, Democrats currently have five out of nine of the state's seats in the House of Representatives.
The bottom line: This seat will be a top-tier Senate race this year, and Bayh's retirement has probably damaged the Dems' chances of holding it.
Additional reporting by Christina Bellantoni.