Article Photos: Romney's drop weakens GOP effort to take Senate



LAS VEGAS, NV - SEPTEMBER 21: Republican presidential candidate, former Massachusetts Gov. Mitt Romney speaks at a campaign event at the Cox Pavilion on September 21, 2012 in Las Vegas, Nevada. Romney and his wife, Ann, paid $1.94 million, 14.1% of their $13.7 million income for 2011. (Photo by David Becker/Getty Images)

LAS VEGAS, NV - SEPTEMBER 21: Republican presidential candidate, former Massachusetts Gov. Mitt Romney speaks at a campaign event at the Cox Pavilion on September 21, 2012 in Las Vegas, Nevada. Romney and his wife, Ann, paid $1.94 million, 14.1% of their $13.7 million income for 2011. (Photo by David Becker/Getty Images)