Troops Defending the Homeland: The Posse Comitatus Act and the Legal Environment for a Military Role in Domestic Counter Terrorism

The United States has been unique in entrusting law enforcement to civilian forces, at the lowest levels of government in its federal system. Its revolutionary and constitutional heritage likewise led to a sharp separation of civilian and military spheres of government, and to the subordination of the military to civilian authority. Although the domestic deployment of troops has occurred throughout US history, the Posse Comitatus Act of 1878 established a presumption against the use of the military to enforce the laws. While the Posse Comitatus Act remains as a symbol of the nation's distaste for military involvement in civilian law enforcement, concerns about homeland defense and catastrophic terrorism have led many to anticipate an enhanced role for the military in defending the homeland. The article reviews these recent developments and assesses the legal and practical problems that this trend portends.