The State is a group of people who have managed to acquire a virtual monopoly of the use of violence throughout a given territorial area. In particular, it has acquired a monopoly of aggressive violence, for States generally recognize the right of individuals to use violence (though not against States, of course) in self-defense. The State then uses this monopoly to wield power over the inhabitants of the area and to enjoy the material fruits of that power. The State, then, is the only organization in society that regularly and openly obtains its monetary revenues by the use of aggressive violence; all other individuals and organizations (except if delegated that right by the State) can obtain wealth only by peaceful production and by voluntary exchange of their respective products. This use of violence to obtain its revenue (called “taxation”) is the keystone of State power. Upon this base the State erects a further structure of power over the individuals in its territory, regulating them, penalizing critics, subsidizing favorites, etc.
War, peace and the State, Murray Rothbard
via Diamond age