Tea Party-backed Mourdock won the primary against longtime Indiana Sen. Richard Lugar. Donnelly, his challenger, has repeatedly highlighted his Tea Party ties and his extreme conservatism. The race is tight, and has garnered national attention. Republicans have made a big push to gain seats in the Senate, and while the Indiana race initially looked likely to fall Republican, it has grown closer in recent weeks.
Akin is also in a tight race for a U.S. Senate seat with Democrat Claire McCaskill. While both men have drawn the ire of Democrats and some Republicans,
Akin's assertion that women's bodies can reject pregnancy in instances of "legitimate rape" is blatantly false.
Mourdock's comments, while controversial and offensive to some, are somewhat less inflammatory. The timing is also different. Akin's comments came with enough time for him to withdraw and allow the Republican party to put in another, potentially viable candidate. Mourdock's remarks were less than two weeks before the election, meaning any call to withdraw would be futile.
This story was updated to reflect comments Mourdock made at a news conference.