Defense Secretary James Mattis has "hit the ground running" at the Pentagon, starting his first full day with an intelligence briefing and appointing his chief of staff and senior military assistant, Defense Department spokesman Capt. Jeff Davis said Monday. Kevin Sweeney, a retired Navy rear admiral who worked with the new defense secretary at U.S. Joint Forces Command and U.S. Central Command, will serve as Mattis' chief of staff, and Rear Adm. Craig Faller, who recently served as the Navy's...