Governments and societies have been contemplating the appropriateness of newly defined or previously secondary purposes for their armed forces, which extend beyond their core role of national defense. These include the assignment of a variety of external and internal military and civilian roles and tasks. Some of these are performed as a subsidiary activity in support of operations under civilian command. An examination of the internal roles of the armed forces in 15 Western democracies shows that armed forces assist in internal security provision mainly as a resource of last resort when efforts are required to respond to exceptional situations. This is the case primarily during and after natural and humanitarian catastrophes as well as other emergencies that exceed the response capacities of civilian and hybrid security institutions. Under the command and control of civilian agencies, the usually subsidiary operations of the armed forces are designed to enhance the capacity of civilian security providers in such situations. What does this mean for armed forces in the developing countries in their indigenous state-building processes? What are the implications for donor nations from the North in their efforts towards “building partner capacity?”