The idea of the state is not simply that the state, like any institution, is an idea, but that it is an idea of a certain kind, specifically, one that encompasses in an authoritative manner a society's understanding of how things in the world really are. As such, it is best conceived as the intelligible foundation for all decisions about how the various instruments of government can and should be utilized in order to achieve social goals. I have already dealt at length with much of what is included in this formulation. I have discussed what it means to think systematically about how things in the world really are, and also what it means to talk prudentially about the instrumentality of government as opposed to philosophically about the nature of the state itself. But I have not yet discussed the sense in which the idea of the state is authoritative.

Our intuition is that the state, properly understood, is distinguished from other institutions not only in the scope of its activity – the topic of chapter 4 above – but in the nature of the authority that it exercises over its citizens. This involves, presumably, a variety of related intuitions: the state is sovereign or contains a sovereign element, its rule is morally defensible, its citizens have a responsibility to obey the laws that it promulgates, and so on. I believe that understanding fully the idea of the state requires us to explicate these intuitions, to demonstrate their underlying logic.