Former Massachusetts Gov. Mitt Romney arrives for a rally at Missouri Valley Steel in Sioux City, Iowa, on Friday, Dec. 16, 2011, in his bid for the Republican presidential nomination. (AP Photo)

Photo by: Chris Carlson

Former Massachusetts Gov. Mitt Romney arrives for a rally at Missouri Valley Steel in Sioux City, Iowa, on Friday, Dec. 16, 2011, in his bid for the Republican presidential nomination. (AP Photo)