National security -- 47 Foreign relations -- 16 Terrorism -- 15 Prevention. -- 9 World politics -- 8 Military policy 7 Government policy -- 6 more ... War on Terrorism, 2001-2009 6 Foreign relations 5 Intelligence service -- 4 Military relations -- 4 National security 4 Security, International 4 Civil defense -- 3 Defenses 3 History -- 3 Politics and government -- 3 Prevention -- 3 International relations 2 Law and legislation -- 2 North Atlantic Treaty Organization 2 Relations -- 2 Security measures 2 Security measures -- 2 September 11 Terrorist Attacks, 2001 2 Terrorism 2 War (International law) 2 Weapons of mass destruction 2 1976- 1 20th century. -- 1 less ...