Civil defense -- Terrorism -- 6 Prevention. -- 4 Defenses 3 National security -- 3 Emergency management -- 2 War on Terrorism, 2001-2009 2 more ... Armed Forces -- 1 Citizen participation -- 1 Civil defense 1 Disaster relief -- 1 Harbors -- 1 Law enforcement -- 1 Merchant marine -- 1 Military planning -- 1 National security 1 Organization 1 Politics and government -- 1 Prevention 1 Prevention -- 1 Security measures 1 Security measures -- 1 Self-defense -- 1 less ...