WASHINGTON — With a Nobel Peace Prize in hand, President Barack Obama returned to the grind of governing, refocusing on his top domestic priority as the Senate moves toward a pivotal moment on legislation to remake the nation's health care system. Obama arrived Friday from Norway after becoming the first chief executive to collect the storied award so early in his tenure. He blitzed through his Nobel itinerary, then met privately with U.S. embassy staff at his hotel in Oslo before returning to a huge agenda hanging in the balance, including health care and another European trip next week for...