Intelligence service History 109 National security 63 Terrorism 53 Prevention 39 Military intelligence 32 Foreign relations 28 Secret service 28 Espionage 25 Politics and government 19 Cold War 18 Government policy 18 Law and legislation 17 Spies 15 Electronic surveillance 12 Intelligence officers 12 Internal security 12 September 11 Terrorist Attacks, 2001 12 World War, 1939-1945 12 Evaluation 10 Law enforcement 9 Political aspects 9 Methodology 8 Civil rights 7 Officials and employees 7 Presidents 7 International cooperation 6 Iraq War, 2003-2011 6 Management 6 Moral and ethical aspects 6