Senator Evan Bayh to Retire

Sen. Evan Bayh of Indiana is expected to announce this afternoon that he will not run for reelection.

Politico cites two senior Democratic sources and TheIndianapolis Star, which reported prepared remarks in which Bayh, a Democrat, will say that his desire to serve in Congress has "waned."

"Bayh, who served two terms as governor of Indiana before winning election to the Senate in 1998, was favored to win another term this November," reports Politico. "A poll last week showed him leading two of his prospective opponents, former Republican Sen. Dan Coats and former Rep. John Hostettler, by wide, double-digit margins."

The announcement is anticipated to spark an intense battle for the seat in conservative-leaning Indiana.