President Barack Obama waves as he walks across the South Lawn of the White House after returning from Camp David on Marine One helicopter, Sunday, Aug., 26, 2012. (AP Photo/Pablo Martinez Monsivais)

Photo by: Pablo Martinez Monsivais

President Barack Obama waves as he walks across the South Lawn of the White House after returning from Camp David on Marine One helicopter, Sunday, Aug., 26, 2012. (AP Photo/Pablo Martinez Monsivais)