Man, the State, and War: A Theoretical Analysis

Waltz distinguishes three levels of analysis for the causes of war. The first image locates causes in human nature—aggression, selfishness, and misdirected impulses. The second image finds causes in the internal structure of states, such as whether they are democratic or authoritarian, capitalist or socialist . The third image identifies international anarchy—the absence of a global sovereign—as the fundamental structural condition. Waltz argues that while all three images contribute, the third image provides the permissive cause: even if every individual and state were good, conflicts of interest would arise, and in anarchy nothing prevents their violent resolution .

Waltz argues that human nature is too complex to serve as a reliable causal explanation. He writes that 'human nature is so complex that it can justify every hypothesis that we may entertain' —it explains both war and peace, making it useless for accounting for variation in outcomes . First-image optimists, he contends, betray a 'naivete in politics' by treating human nature as simple and changeable. If human nature is constant, it cannot explain why war occurs sometimes and not others. Yet Waltz also rejects the counterargument that a constant factor cannot explain variable outcomes, a contradiction critics later identified in his shift to structural realism .

The third image locates the cause of war in international anarchy—the absence of a central authority above states. Waltz argues that this structural condition creates a 'self-help' system where states must rely on their own capabilities for security. Even if all actors were benevolent, anarchy would still generate conflict because nothing prevents a state from using force . This third-image framework, developed in Man, the State, and War, became the foundation for Waltz's later structural realism in Theory of International Politics (1979). As one scholar notes, 'the exposition of the third image lays the foundation for the systemic theory of realism that he develops later' .

Waltz's shift between the two books involved a significant, largely unacknowledged reversal. In Man, the State, and War, he argued that a constant factor—like human nature—cannot explain variable outcomes like war and peace. This argument targeted classical realists like Morgenthau. But in Theory of International Politics, Waltz argued the opposite: that a variable factor cannot explain a constant outcome (the persistence of war). This reversal, critics argue, was necessary because his original argument 'also militated against his structural realism' . Waltz never publicly reconciled these two positions, and the contradiction remains a point of scholarly critique .

Waltz's typology provided the 'nascent discipline' of IR with an organizing framework that persists in graduate seminars today . The three images map directly onto levels of analysis—individual, state, and system—that structure research agendas across paradigms. First-image research includes psychological and behavioral approaches; second-image research includes democratic peace theory and comparative foreign policy; third-image research includes structural realism and systemic theories. As Robert Art and Robert Jervis noted, Waltz's 'lasting contribution was to provide a typology for the causes of war which helped to organize the then nascent discipline' .

A frequent misreading treats the three images as mutually exclusive alternatives, with Waltz simply choosing the third and dismissing the first two. In fact, Waltz insists that all three images must be included in any complete analysis. His argument is about causal priority, not exclusion: the third image provides the necessary structural condition, but human behavior and state characteristics remain relevant for explaining particular wars . Waltz himself wrote that 'strictly speaking, Man, the State, and War did not present a theory of international politics. It did, however, lay the foundation for one' . The book is a framework for analysis, not a finished theory.