Prevention -- Terrorism -- 28 Government policy -- 15 National security -- 8 Foreign relations -- 6 History -- 5 Civil rights -- 4 more ... Emergency management -- 4 Civil defense -- 3 Politics and government -- 3 Terrorism 3 Defenses 2 Economic sanctions, American 2 Government policy 2 Military policy 2 Politics and government 2 Prevention 2 Relations 2 Security measures -- 2 War on terrorism, 2001- 2 Weapons of mass destruction 2 Administrative agencies -- 1 Asymmetric warfare -- 1 Biological warfare 1 Biological weapons 1 Bioterrorism -- 1 Case studies 1 Citizen participation -- 1 Computer networks -- 1 Computer security -- 1 less ...