Government policy Terrorism 78 Prevention 44 National security 23 Foreign relations 21 History 17 War on terrorism, 2001- 13 United States 10 Nuclear weapons 9 Politics and government 8 Human rights 7 Intelligence service 7 Military policy 7 Emigration and immigration 6 Political aspects 6 September 11 Terrorist Attacks, 2001 6 Bioterrorism 5 Economic conditions 5 International cooperation 5 Environmental policy 4 Islam and politics 4 Jihad 4 Law and legislation 4 Marine resources 4 Nuclear nonproliferation 4 Religious aspects 4 Agriculture and state 3 Case studies 3 Climatic changes 3 Cross-cultural studies 3