FILE - In this July 16, 2012 file photo, President Barack Obama campaign at the Cincinnati Music Hall in Cincinnati. Barack Obama's backers roll out a new ad assailing Mitt Romney's bus

 

              FILE - In this July 16, 2012 file photo, President Barack Obama campaign at the Cincinnati Music Hall in Cincinnati. Barack Obama
FILE - In this July 16, 2012 file photo, President Barack Obama campaign at the Cincinnati Music Hall in Cincinnati. Barack Obama's backers roll out a new ad assailing Mitt Romney's business record at Bain Capital, while the Republican candidate seeks to paint the Democrat as a big-government liberal. (AP Photo/Susan Walsh, File)