Republican presidential candidate and former Massachusetts Gov. Mitt Romney speaks at a campaign fundraising event at Red Rock Hotel and Casino in Las Vegas, Friday, Sept. 21, 2012. (AP Photo/Charles Dharapak)

Photo by: Charles Dharapak

Republican presidential candidate and former Massachusetts Gov. Mitt Romney speaks at a campaign fundraising event at Red Rock Hotel and Casino in Las Vegas, Friday, Sept. 21, 2012. (AP Photo/Charles Dharapak)