Harold Thomas Martin, a 51-year-old US National Security Agency contractor from Maryland, may be remembered as the second Edward Snowden, although there are many differences between the two cases. Martin, a former US Navy officer with top secret national security clearance, was arrested on Aug. 27 by the FBI and charged with the unauthorized removal and retention for many years of highly-sensitive classified documents. The purloined materials found in raids of his home and his car, which were described by as capable of causing “exceptionally grave damage” to US national security. Like Snowden, Martin worked for Booz Allen Hamilton, which...