President Barack Obama walks in with Maj. Gen. Michael S. Linnington, Commander of the U.S. Army Military District of Washington, before placing a wreath at the Tomb of the Unknowns during a Veterans Day ceremony at Arlington National Cemetery in Arlington, Va., Friday, Nov. 11, 2011. (AP Photo/Pablo Martinez Monsivais)

Photo by: Pablo Martinez Monsivais

President Barack Obama walks in with Maj. Gen. Michael S. Linnington, Commander of the U.S. Army Military District of Washington, before placing a wreath at the Tomb of the Unknowns during a Veterans Day ceremony at Arlington National Cemetery in Arlington, Va., Friday, Nov. 11, 2011. (AP Photo/Pablo Martinez Monsivais)