Duckworth lost both of her legs in the war, and it became a flashpoint in the race when Walsh said that her service was the only issue she was campaigning on.

Walsh is one of the most outspoken members of the Tea Party freshman class.

He came under fire in mid-October after saying that abortions are "absolutely" never necessary to save the lives of pregnant women because of advances in medical technology. He later edged away from the comment, made after a debate with Duckworth, and said an abortion might be required to save a woman's life in "very rare circumstances." 

—This post was updated at 10:47 p.m.