The coordinated, focused application of deadly force is the primary reason why we have armed forces. This chapter attempts to answer the question of what considerations should be examined in determining whether the military should provide support to civil authority. Armed forces exist to defend the nation against external threats; to the extent that they are engaged in DSCA tasks, they may not be available to carry out their primary missions of national defense, as there is always an opportunity cost to pay. Most European states have very strict rules which govern the employment of deadly force under circumstances which are not related to the defense of the homeland against external threats. Occasionally, there are law enforcement organizations that have some military characteristics, capabilities and functions, such as France's Gendarmerie or the US Coast Guard, but even these organizations are law enforcers in the first instance and warriors in the second.