"Active shooter attacks appear to occur more in the United States than other countries and some data shows that their rate of occurrence has increased in the past several years. In response, institutions such as the Department of Defense (DoD), other federal agencies, police, and education systems have increased security and adapted response procedures. Despite ongoing efforts, active shooter attacks occurred in Fort Hood, Texas in 2009, the Washington Navy Yard in 2013, and Chattanooga, Tennessee in 2015. Regardless of the level of security, it appears that the proliferation of firearms in combination with radicalization through the Internet have facilitated more individuals to perpetrate active shooter attacks. These attacks also appear to have similar characteristics whether conducted on DoD installations or in other areas. This thesis studies a variety of available military documents, active shooter case studies, and other active shooter defeat strategies to determine if the military could benefit from increased numbers of armed personnel to augment military and civilian law enforcement personnel. The benefit to the DoD includes increased probability of prevention and deterrence of active shooter events, and a more efficient mitigation and defeat mechanism to reduce casualty rates and terminate the event."