Joe Donnelly, Indiana Democratic candidate for U.S. Senate, casts his vote Tuesday Nov. 6, 2012 in South Bend, Ind. Donnelly is running for the Senate seat that was held by Republican Richard Lugar who lost in the primary to Richard Murdock. (AP Photo/Joe Raymond)

Republican Richard Mourdock, a candidate for Indiana's U.S. Senate seat, laughs as he is interviewed outside a polling place in Indianapolis, Tuesday, Nov. 6, 2012. Mourdock is running against Democrat Joe Donnelly. (AP Photo/Michael Conroy)

Joe Donnelly, Indiana Democratic candidate for U.S. Senate, and his wife Jill wait to cast their vote Tuesday Nov. 6, 2012 in South Bend, Ind. Donnelly is running for the Senate seat that was held by Republican Richard Lugar who lost in the primary to Richard Murdock. (AP Photo/Joe Raymond)

Republican Richard Mourdock, a candidate for Indiana's U.S. Senate seat, greets voters and supports outside a polling place in Indianapolis, Tuesday, Nov. 6, 2012. Mourdock is running against Democrat Joe Donnelly. (AP Photo/Michael Conroy)

FILE - In this Sept. 26, 2012 file photo, Indiana Democratic Senate candidate Joe Donnelly answers questions during an interview with the Associated Press in Indianapolis. Donnelly's opponent, Richard Mourdock, is backing away from the tea party rhetoric that helped him knock off veteran Sen. Richard Lugar in the GOP primary as he tries to woo moderate voters. Mourdock once declared that bipartisanship means Democrats coming to Republicans' way of thinking. Now, he's voicing support for parts of President Barack Obama's health care overhaul and has aired campaign ads touting his ability to compromise. (AP Photo/Michael Conroy, File)

Donnelly

Republican candidate of U.S. Senate Richard Mourdock answers questions during an interview with the Associated Press in Indianapolis, Thursday, Sept. 27, 2012. Mourdock is running against Democrat Joe Donnelly to replace Richard Lugar. (AP Photo/Michael Conroy) (AP Photo/Michael Conroy)