Terrorism -- 56 Prevention. -- 23 Foreign relations -- 18 War on Terrorism, 2001-2009 13 National security -- 12 Government policy -- 11 Politics and government -- 10 more ... Prevention -- 10 History -- 8 Islam 7 Prevention 7 Religious aspects -- 7 September 11 Terrorist Attacks, 2001 7 Terrorism 6 Civil defense -- 5 Military policy 5 Security measures 5 Intelligence service -- 4 Islam and politics -- 4 Islamic fundamentalism 4 Islamic fundamentalism -- 4 Politics and government 4 Security measures -- 4 War and emergency powers -- 4 Aeronautics, Commercial -- 3 Civil rights -- 3 Defenses 3 Democracy -- 3 Emergency management -- 3 History. -- 3 less ...