Republican presidential candidate, former Massachusetts Gov. Mitt Romney, listens to a question from a reporter as he visits a campaign call center in Livonia, Mich., Tuesday, Feb. 28, 2012. (AP Photo/Gerald Herbert)

Photo by: Gerald Herbert

Republican presidential candidate, former Massachusetts Gov. Mitt Romney, listens to a question from a reporter as he visits a campaign call center in Livonia, Mich., Tuesday, Feb. 28, 2012. (AP Photo/Gerald Herbert)