Neorealism, also called structural realism, argues that the international system influences state behavior based primarily on the distribution of power. It views states as acting to maximize their security in an anarchic system, which leads them to engage in a self-help balance of power. The theory was first established by Kenneth Waltz in his 1979 book Theory of International Politics, departing from classical realism by arguing that the structure of the international system, not human nature, determines state actions.