Defenses National security -- 6 Civil defense -- 4 Military policy 4 Terrorism -- 3 Armed Forces 2 Armed Forces -- 2 more ... Emergency management -- 2 Military relations -- 2 Prevention -- 2 War on Terrorism, 2001-2009 2 Weapons of mass destruction 2 World politics -- 2 Armed forces 1 Armed forces -- 1 Asymmetric warfare -- 1 Civil defense 1 Disaster relief -- 1 Foreign relations -- 1 Government policy -- 1 Harbors -- 1 Merchant marine -- 1 Military art and science 1 Military planning -- 1 Military readiness 1 National security 1 Nuclear terrorism 1 Nuclear weapons -- 1 Operational readiness. -- 1 Organization 1 less ...