Terrorism -- Prevention. -- 21 Government policy -- 16 Prevention -- 14 Foreign relations -- 13 National security -- 11 War on Terrorism, 2001-2009 11 more ... Terrorism 9 Islam 8 Religious aspects -- 8 Politics and government -- 7 September 11 Terrorist Attacks, 2001 7 History -- 6 Prevention 6 Terrorists -- 6 Islamic fundamentalism -- 5 Psychological aspects 5 Security measures 5 Civil defense -- 4 Islamic fundamentalism 4 Politics and government 4 Aeronautics, Commercial -- 3 Civil rights -- 3 Intelligence service -- 3 Jihad 3 Security measures -- 3 September 11 Terrorist Attacks, 2001 -- 3 War on terrorism, 2001- 3 Economic sanctions, American 2 Emergency management -- 2 less ...