WASHINGTON — Representative John P. Murtha, chairman of the House military spending subcommittee and a decorated former Marine, has long acted as a protective Uncle Jack to the Marine Corps. Brendan Hoffman/Bloomberg News A nephew of John P. Murtha, chairman of the House military spending panel, has been named a Marine legislative liaison. Now the corps has named one of his nephews, Col. Brian Murtha, to the office charged with advocating for its interests on Capitol Hill, where Representative Murtha, Democrat of Pennsylvania, helps write the military budget. In relocating to be near the Pentagon, Colonel Murtha has even moved...