Transnational threats, such as terrorism and international drug crime, and civil disturbances bode future domestic support operations in the realm of law enforcement for the U.S. military. The reserve components will play a key role in the growing homeland defense mission and will have to be integrated into the mission to provide the United States with an effective deterrent to potential domestic crises. The Posse Comitatus Act (PCA) generally precludes the use of federal forces to perform law enforcement actions. There are numerous constitutional and statutory exceptions to the PCA which allow U.S. military forces to conduct law enforcement operations. This paper examines national and military strategy focused on the homeland defense policy within the context of the ends-ways-means model. Countervailing civil-military relations policy concerns arising out of the PCA are identified and the history of federal forces use under the PCA discussed. Finally recommendations are made for an overarching homeland defense policy.