Marine Gunnery Sgt. Gary Maziarz said patriotism motivated him to join a spy ring, smuggle secret files from Camp Pendleton and give them to law enforcement officers for anti-terrorism work in Southern California. He knew his group was violating national security laws. But he said bureaucratic walls erected by the military and civilian agencies were hampering intelligence sharing and coordination, making the nation more vulnerable to terrorists. Details of Maziarz's case emerged after he pleaded guilty to mishandling more than 100 classified documents from 2004 to last year. The overall breach could be far larger: Investigators believe that as far...