(FILES)This combination of file pictures shows US President Barack Obama (L) speaking during a campaign event at Prime Osborn Convention Center July 19, 2012 in Jacksonville, Florida, and US Republican presidential hopeful Mitt Romney (R) addressing the Family Research Council's Values Voter Summit in Washington on October 8, 2011.  Republican challenger Mitt Romney will make a last-minute play for Pennsylvania NOvember 4, 2012 as he and President Barack Obama criss-cross America in a final push for votes on the penultimate day of their tense White House campaign.  AFP PHOTO/Mandel NGAN /Nicholas KAMM/FILES