DON'T USE THIS CAPTION XXXXX DON'T USE THIS CAPTION President Barack Obama returns a salute to Navy Adm. Eric T. Olson, commander of U.S. Special Operations Command, as he steps off Air Force One at Campbell Army Airfield in Fort Campbell, Ky., Friday, May 6, 2011. (AP Photo/Charles Dharapak)

DON'T USE THIS CAPTION XXXXX DON'T USE THIS CAPTION President Barack Obama returns a salute to Navy Adm. Eric T. Olson, commander of U.S. Special Operations Command, as he steps off Air Force One at Campbell Army Airfield in Fort Campbell, Ky., Friday, May 6, 2011. (AP Photo/Charles Dharapak)