Terrorism -- Emergency management -- 6 National security -- 5 Prevention -- 5 Prevention 4 Military policy 2 Safety measures 2 more ... Security Management 2 Security measures 2 Transportation -- 2 United States 2 Citizen participation -- 1 Civil defense -- 1 Congresses 1 Crisis management 1 Crisis management -- 1 Emergency communication system -- 1 Emergency management 1 Foreign relations -- 1 Freight and freightage -- 1 Geographic information systems 1 Geography 1 Government policy 1 Homeland security 1 Hostages 1 Infrastructure -- 1 International business enterprises 1 International relations 1 Natural disasters -- 1 Political planning -- 1 less ...