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