President Barack Obama and Vice President Joe Biden, accompanied by Maj. Gen. Michael S. Linnington, Commander of the U.S. Army Military District of Washington, listen to Taps after placing a wreath at the Tomb of the Unknowns at Arlington National Cemetery in Arlington, Va., Sunday, Jan. 20, 2013.  &#40;AP Photo&#47;Susan Walsh&#41; <span class=meta>(AP Photo&#47; Susan Walsh)</span>