Most traditional theories of international relations have tended to reify states as actors in their own right, a habit encouraged by the practice of writing, say, "Germany adopted" such and such a policy. But in practice, states are institutions whose policies are set by human policymakers, and it has been suggested that a fruitful interpretation of international relations and particularly of war might better be rooted in examination of the psychological characteristics and behavior of leaders and policymakers.
The simplest psychological theory of war is that it is instinctive. The central difficulty of this theory is that it does not explain peace (Sullivan, n.d., p. 26). Humans must indeed be instinctively capable of war, as of other kinds of violent aggression, but a usable theory must tell us why war is made under certain conditions, and not under others. Clearly, if a model of war is to be based on the psychology of leaders, it must find a more robust premise than the simple observation that they can make war, it must explain why they sometimes do make war.
One class of theories, psychological or psychoanalytic in character, has sought to identify the causes of war in personality disorders of warmakers. These theories have no doubt gained some credibility from the circumstances of this century's chief war, the Second World War. Leaders such as Hitler and Stalin have lent themselves to psychological interpretations of policy behavior (Vogler, 1989, p. 143). It is not at all difficult to argue that both were psychopaths, and that the wars involving them were, particularly perhaps in Hitler's case, an expression of this psychopathology.
As prominent as such mentally unstable men have been in the wars of the twentieth century, however, they have not been the cause of all of them. When we broaden the picture, we find a more complex picture. Personality theories encounter the difficulty that shifts in policy rela...