President Obama on Monday nominated Chuck Hagel as defense secretary. The former Nebraska senator will have to be confirmed by the Senate, and a fight is expected. Although he's a Republican, Hagel has many opponents in the GOP, and there has been controversy over his past views on gay rights and his position on Iran.

Hearings will be held by the Senate Armed Services Committee. Here's how U.S. senators on and off the committee are lining up on the nomination.