Terrorism -- 31 Prevention -- 15 Prevention 11 Terrorism 9 Government publications -- 7 Radicalism -- 5 Government policy -- 4 more ... International cooperation 4 National security -- 4 Security clearances -- 4 Emigration and immigration 3 Government policy 3 Islam 3 Politics and government 3 Prevention. -- 3 Radicals -- 3 Religious aspects -- 3 Territorial waters -- 3 War on terrorism, 2001- 3 Case studies 2 Computer crimes 2 Cyberterrorism 2 Internal security -- 2 Psychological aspects 2 Security, International 2 Aeronautics, commercial -- 1 Airports -- 1 Cae studies 1 Case studies -- 1 Congresses -- 1 less ...