Similarly, when two citizens have a dispute, they can appeal to the courts to render a verdict and, more importantly, the law enforcement agencies to enforce the court's ruling, but there is no body above nation-states that is capable of establishing rules or laws for all the states, deciding how these apply in specific cases, and compelling the states to honor the court's ruling. As a result, if an issue at stake is important enough to a state, it can achieve a satisfactory outcome only by using its power to impose its will on another state(s). The realization that at any point in time any state can resort to armed force, forces each state always be prepared for that contingency. These themes are fleshed out more fully in "Theory of International Politics" which, as the title suggests, lays out a theory for international politics as a whole rather than the narrower focus on what causes war.