The monopoly on violence (German: Gewaltmonopol des Staates) is the conception of the state expounded by Max Weber in Politics as a Vocation. According to Weber, the state is that entity which claims a monopoly on the legitimate use of violence, which it may therefore elect to delegate as it sees fit. Weber's conception of the state as holding a monopoly on violence has figured prominently in philosophy of law and political philosophy in the twentieth century.
It defines a single entity, the state, as exercising authority on violence over a given territory; territory was also deemed by Weber to be a prerequisite feature of a state. Such a monopoly, according to Weber, must occur via a process of legitimation, wherein a claim is laid which legitimises the state's use of violence.
According to Raymond Aron, international relations are characterized by the absence of the monopoly on violence in the relationship between states.[1]
Max Weber wrote in Politics as a Vocation that a necessary condition of statehood is the retention of such a monopoly. His expanded definition was that something is "a 'state' if and insofar as its administrative staff successfully upholds a claim on the monopoly of the legitimate use of violence (German: das Monopol legitimen physischen Zwanges) in the enforcement of its order."[2][3]
According to Weber, the state is the source of legitimacy for any use of violence. The police and the military are its main instruments, but this does not mean that only public force can be used: private force (as in private security) can be used too, as long as it has legitimacy derived from the state.
Weber applied several caveats to this basic principle.
One implication of the above is that states that fail to control the use of coercive violent force (e.g., those with unregulated militias) are essentially not functional states. Another is that all such "functional" states function by reproducing the forms of violence that sustain existing social power relationships, and suppressing the forms of violence that threaten to disrupt them.