A vendor sells a booklet of the Democratic Convention at the Carolina Fest street festival during preparations for the Democratic National Convention (DNC) in Charlotte, North Carolina, the United States, Sept. 3, 2012. President Barack Obama is to be named the Democratic Party's nominee during the DNC, which is scheduled to be held from Sept. 4 to Sept 7. (Xinhua/Zhang Jun)
A supporter of U.S. President Barack Obama (L) argues with a protestor at the Carolina Fest street festival during preparations for the Democratic National Convention (DNC) in Charlotte, North Carolina, the United States, Sept. 3, 2012. President Barack Obama is to be named the Democratic Party's nominee during the DNC, which is scheduled to be held from Sept. 4 to Sept 7. (Xinhua/Zhang Jun)