The existence of a clear-cut division between “civil and military” is in many ways a foundation for international law and diplomacy. It is also a given starting point in many studies on current issues relating to war and peace, as well as in historical interpretations of past conflicts. Yet the civil–military dichotomy is not always a useful way of approaching complex matters, and by adopting such a starting point, some issues risk being overlooked. There are numerous historical examples, from the American Civil War, to wars of national liberation ending colonialization, to insurrections shaking political status quo such as the Marxist–Leninist revolutions; all illustrate that neither the agents of war nor the victims fit neatly into one of two clear categories. In a contemporary setting, non-traditional forms of warfare that make use of cyber space or autonomous systems further serves not only to undermine ideas of internal–external security but also to blur the distinction between civil and military. In the everyday making and implementation of policy, these concepts are indeed fluid and the borders between them highly variable, continuously contested, and renegotiated. As concepts, they can be seen as co-constitutive in the everyday usage. Civil and military are therefore best understood as norms, whose contents and interrelationship are contextually determined. At the same time, civil and military are organizational principles of the state, and as such the distinction is, arguably, too important, too deep-seated within the modern state- system, and too engrained in how legal and political order are understood to disappear in the near future.