Not running: Mike Huckabee, the 2008 runner-up; John Thune, the likeliest candidate from the Senate, the body that has produced the out-party candidate in 2008, 2004, and 1996; Mike Pence, who could lay as much claim as anyone to represent the conservative movement; and Haley Barbour and Mitch Daniels, effective two-term governors with impressive D.C. experience as well.