President Barack Obama waves as he boards Air Force One before his departure from Andrews Air Force Base, Md., Tuesday, Sept., 4, 2012. (AP Photo/Pablo Martinez Monsivais)

Photo by: Pablo Martinez Monsivais

President Barack Obama waves as he boards Air Force One before his departure from Andrews Air Force Base, Md., Tuesday, Sept., 4, 2012. (AP Photo/Pablo Martinez Monsivais)