Republican presidential candidate Mitt Romney smiles as he talks with his staff aboard his campaign bus after a stop in Council Bluffs, Iowa, on Friday, June 8, 2012. (AP Photo/Evan Vucci)
** FILE ** In this May 8, 2012, file photo, President Barack Obama speaks in Washington. (AP Photo/Evan Vucci, File)
Republican presidential candidate Mitt Romney speaks at the Latino Coalition's annual economic summit at the U.S. Chamber of Commerce in Washington on Wednesday, May 23, 2012. (AP Photo/Evan Vucci)
Republican presidential candidate Mitt Romney speaks at the Latino Coalition's annual economic summit at the U.S. Chamber of Commerce in Washington on Wednesday, May 23, 2012. (AP Photo/Evan Vucci)
** FILE ** In this May 8, 2012, file photo, President Barack Obama speaks in Washington. (AP Photo/Evan Vucci, File)
** FILE ** In this May 8, 2012, file photo, President Barack Obama speaks in Washington. (AP Photo/Evan Vucci, File)
** FILE ** In this May 8, 2012, file photo, President Barack Obama speaks in Washington. (AP Photo/Evan Vucci, File)
Ryan Zimmerman missed the Washington Nationals' game against the Miami Marlins on Saturday with shoulder inflammation. (AP Photo/Evan Vucci)
Miami Heat center Eddy Curry, right, drives to the basket against Washington Wizards forward Kevin Seraphin during the first half of an NBA basketball game on Thursday, April 26, 2012, in Washington. (AP Photo/Evan Vucci)
