The balance of power

Like disarmament, the balance of power is a systemic response to the need for order. Unlike disarmament, the balance of power cuts with rather than against the grain of international politics. Disarmament would require the restructuring of the international system according to the principle of hierarchy. The balance of power takes advantage of the system's natural anarchy, and of the impulses for self-aggrandizement and selfdefense to which anarchy lends itself. Rather than calling for a drastic change in the way that states conduct their affairs, the balance of power, defined as the tendency of the international system toward an equilibrium in which no single state dominates the others, is a means by which the characteristic behavior of states yields a kind of harmony. It is an ancient feature of politics among sovereign political communities, which the nuclear revolution has helped to revive.

Thucydides records three occasions on which efforts to establish hegemony were thwarted. As his story begins, a coalition of Greek city–states has repelled an invasion by Persia. Then, when the Athenians bid to dominate Greece, other city–states coalesce to stop them.