Civil defense -- Terrorism -- National security -- 5 Prevention. -- 4 Prevention -- 3 Defenses 2 Emergency management -- 2 more ... Citizen participation -- 1 Civil defense 1 Civil rights -- 1 Government policy -- 1 Harbors -- 1 Law enforcement -- 1 Merchant marine -- 1 National security 1 Politics and government -- 1 Prevention 1 Security measures 1 Security measures -- 1 Self-defense -- 1 War on Terrorism, 2001-2009 1 less ...