Merchant marine -- 2 National security -- Security measures -- Civil defense 1 Civil defense -- 1 Congresses -- 1 Defenses 1 more ... Harbors -- 1 Maritime terrorism -- 1 National security 1 Politics and government -- 1 Prevention 1 Prevention -- 1 Security measures 1 Terrorism -- 1 War on Terrorism, 2001-2009 1 less ...