Whether or not warfare was essential to the rise of the state, the rise of the state certainly marked a decisive break in the history of warfare—the most important turning point until the gunpowder revolution in early modern Europe, which brought with it a still more potent form of political and military centralization. The cultural balance of power, in which most human societies had been trapped for thousands of years, was replaced by the political balance of power, which has endured to the present day. The cultural trap had loopholes: People could escape from it by “forgetting” about their grievances when “remembering” them would have been inconvenient, by ritualization, by arbitrating their disputes, by moving away. But there was no escape from the political trap, except in circumstances of unusual geographical isolation like those of Old Kingdom Egypt. The political type of warfare, heretofore an occasional and not particularly successful experiment in human history, now broke free of all constraints. War ceased to be an ancient ritual of earth and became a struggle for power and wealth between ruling groups claiming descent from the gods. They began the progressive elimination of primitive societies and primitive ways of war, a process that today is practically completed.
The sheer scale and pervasiveness of warfare in early states justifies these conclusions about its central importance. All early states had standing armies, all were expansionist, and all engaged in chronic interstate warfare that resulted in fewer and fewer states. In Egypt, with its extremely circumscribed geography, the process resulted almost at once in the unification of the Nile Valley under a single ruler, whose theocratic functions thereafter overshadowed his military functions. In Iraq, much less circumscribed and divided among many powerful city-states, the process of unification took longer and was never permanently successful, and the militaristic character of the state became much more pronounced. Not until the twenty-fourth century [B.C.E.] did Sargon of Akkad unite all the cities of the plain into the first hegemonic empire.