Security measures Terrorism -- War on Terrorism, 2001-2009 3 Aeronautics, Commercial -- 2 Evaluation. -- 2 Government policy -- 2 National security -- 2 more ... Prevention 2 Prevention. -- 2 Civil defense 1 Civil defense -- 1 Defenses 1 Harbors -- 1 Homeland security 1 Infrastructure -- 1 Merchant marine -- 1 Military policy 1 National security 1 Politics and government -- 1 Safety measures 1 Security Management 1 Security measures -- 1 Transportation -- 1 United States 1 War on terrorism, 2001- 1 less ...