Newt Gingrich and Rick Santorum

Newt Gingrich and Rick Santorum

Scott Eells/Bloomberg

Newt Gingrich, former U.S. Speaker of the House, left, listens as Rick Santorum, former U.S. Senator, speaks during a presidential debate sponsored by Bloomberg and The Washington Post held at Dartmouth College in Hanover, New Hampshire, on Oct. 11, 2011.