Terrorism -- 26 Prevention -- 12 Foreign relations -- 10 Government policy -- 9 National security -- 8 Prevention 8 Foreign relations 7 more ... Politics and government -- 6 Prevention. -- 6 Military policy 4 War on Terrorism, 2001-2009 4 Defenses 3 History -- 3 Politics and government 3 September 11 Terrorist Attacks, 2001 3 Terrorism 3 Civil defense -- 2 Economic sanctions, American 2 Relations 2 Security measures 2 Terrorists -- 2 War on terrorism, 2001- 2 Air power -- 1 Asymmetric warfare -- 1 Case studies 1 Civil defense 1 Civil rights -- 1 Combatants and noncombatants (International Law) 1 Counterinsurgency -- 1 Cross- cultural studies 1 less ...