This monograph provides an examination of the legal and traditional aspects of Homeland Security in the U.S. and the current framework for managing a domestic Weapons of Mass Destruction (WMD) incident. This monograph examines the DoD's (Armed Forces) historical role in the defense of the nation as well as its role in domestic support operations. The monograph begins with a brief analysis of the emerging threats that the United States faces, and offers a proposed definition for Homeland Security. This is followed by an examination of the evolution of legal considerations when employing federal military forces in a domestic support capacity. It addresses the Posse Comitatus Act and recent refinements to the Act that circumvent its provisions in instances of clearly identified threats to the Nation's interests. The second chapter includes an analysis of Civil Defense and the DoD's participation in past Civil Defense missions. The monograph outlines the current DoD supporting role to both the FBI for Crisis Management and to the FEMA for Consequence Management during a WMD incident. The monograph argues that the current system is adequate and the DoD should not be designated as the LFA for WMD incidents. The monograph recommends the creation of a new Commander-in-Chief (CINC) for Homeland Security. Additional recommendations include some minor changes to both Joint and Army doctrine in regard to Homeland Security, and that the DoD maintain a receptive attitude towards new domestic missions, advocating the temporary execution of non-traditional missions.