Terrorism -- 170 Prevention 103 Prevention -- 50 Terrorism 41 Prevention. -- 32 National security -- 29 Terrorists -- 16 more ... Government policy -- 14 War on Terrorism, 2001-2009 13 Government policy 12 Psychological aspects 11 Security measures 11 International cooperation 10 Islam 8 Religious aspects -- 8 Psychology 7 Civil defense -- 6 Congresses -- 6 Foreign relations -- 6 Politics and government -- 6 Emergency management -- 5 Foreign relations 5 Security, International 5 September 11 Terrorist Attacks, 2001 5 Social aspects 5 War on terrorism, 2001- 5 Aeronautics, Commercial -- 4 Congresses 4 History 4 Intelligence service -- 4 less ...