National security -- Terrorism -- 18 Prevention. -- 11 Prevention -- 5 Strategic aspects 5 War on Terrorism, 2001-2009 5 Government policy -- 4 more ... Military policy 4 Politics and government -- 4 Civil defense -- 3 Defenses 3 Foreign relations 3 Foreign relations -- 3 Intelligence service -- 3 History -- 2 Internal security -- 2 International cooperation 2 Law and legislation 2 National security 2 Piracy -- 2 Politics and government 2 Prevention 2 Relations -- 2 Security measures 2 Security, International 2 September 11 Terrorist Attacks, 2001 2 World politics -- 2 Air power -- 1 Armed Forces 1 Arms control 1 less ...