National security -- Terrorism -- 4 International relations 3 United States 3 Foreign relations 2 Military policy 2 Politics and government 2 more ... Prevention 2 Security Management 2 Armed Forces 1 Economic condition -- 1 Economic development 1 Foreign relations -- 1 Homeland security 1 Infrastructure -- 1 International offenses 1 International security 1 Political elites -- 1 Safety measures 1 Security measures 1 September 11 Terrorist Attacks, 2001 1 Strategic aspects 1 Transportation -- 1 War (International law) 1 War on terrorism, 2001- 1 Weapons of mass destruction 1 World politics 1 less ...