Republican presidential nominee Mitt Romney acknowledges delegates before speaking at the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/Charles Dharapak) Republican presidential nominee Mitt Romney makes his way through delegates before speaking at the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/Charlie Neibergall) Republican presidential nominee Mitt Romney waves to delegates before speaking at the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/Charlie Neibergall) Republican presidential nominee Mitt Romney addresses the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/J. Scott Applewhite) Republican presidential nominee Mitt Romney addresses the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/J. Scott Applewhite) Republican presidential nominee Mitt Romney addresses the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/J. Scott Applewhite) Republican presidential nominee Mitt Romney acknowledges delegates before speaking at the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/Charles Dharapak) Republican presidential nominee Mitt Romney acknowledges delegates before speaking at the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/Charles Dharapak) Republican presidential nominee Mitt Romney acknowledges delegates before speaking at the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/Charles Dharapak) Republican presidential nominee Mitt Romney acknowledges delegates before speaking at the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/Charles Dharapak) Ann Romney waves with her son Tagg as Republican presidential nominee Mitt Romney addresses delegates during the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/Charlie Neibergall) Republican presidential nominee Mitt Romney addresses the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/J. Scott Applewhite) Republican vice presidential nominee, Rep. Paul Ryan and his wife Janna applaud during Republican presidential nominee Mitt Romney's speech at the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/Charlie Neibergall) Republican presidential nominee Mitt Romney addresses the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/J. Scott Applewhite) Republican presidential nominee Mitt Romney addresses the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/J. Scott Applewhite) Republican presidential nominee Mitt Romney waves to delegates before speaking at the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/David Goldman) Republican presidential nominee Mitt Romney addresses delegates during the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/Charlie Neibergall) Republican presidential nominee Mitt Romney shakes hands of delegates before speaking at the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/David Goldman) Republican presidential nominee Mitt Romney shakes hands of delegates before speaking at the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/David Goldman) Republican presidential nominee Mitt Romney speaks delegates before speaking at the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/Lynne Sladky) Republican presidential nominee Mitt Romney hugs a supporter as he walks to the stage during the Republican National Convention in Tampa, Fla., on Thursday, Aug. 30, 2012. (AP Photo/J. Scott Applewhite)