** FILE ** Republican presidential candidate, former Massachusetts Gov. Mitt Romney shakes hands during a campaign stop on Saturday, March 17, 2012, in Bayamon, Puerto Rico. (AP Photo/Evan Vucci)

Photo by: Evan Vucci

** FILE ** Republican presidential candidate, former Massachusetts Gov. Mitt Romney shakes hands during a campaign stop on Saturday, March 17, 2012, in Bayamon, Puerto Rico. (AP Photo/Evan Vucci)