National security -- 10 Terrorism -- 8 Prevention. -- 5 Civil defense -- 2 Defenses 2 Intelligence service -- 2 Military policy 2 more ... Politics and government -- 2 Security measures 2 War on Terrorism, 2001-2009 2 Air power -- 1 Civil defense 1 Emergency management -- 1 Energy policy -- 1 Foreign relations 1 Foreign relations -- 1 Government policy -- 1 Governmental investigations -- 1 Harbors -- 1 Information warfare -- 1 Internal security -- 1 Merchant marine -- 1 National security 1 Nuclear weapons information -- 1 Petroleum industry and trade -- 1 Planning. -- 1 Political violence -- 1 Politics and government 1 Prevention 1 Prevention -- 1 less ...