House Budget Committee Chairman Rep. Paul Ryan, R-Wis. introduces Republican presidential candidate, former Massachusetts Gov. Mitt Romney before Romney spoke at the Grain Exchange in Milwaukee, in this April 3, 2012 file photo. Romney has picked Wisconsin congressman Paul Ryan to be his running mate, according to a Republican with knowledge of the development. They appeared together Saturday Aug. 11, 2012 in Norfolk, Va., at the start of a four-state bus tour to introduce the newly minted GOP ticket to the nation. (AP Photo/M. Spencer Green, File)