Two metaphors began to take hold: the state as a "billiard ball" among
other billiard balls on the pool table of the international system; and the
state as a "black box," whose behavior could be estimated by the study of external
forces without much inquiry into the idiosyncratic contents of the
box, such as domestic politics and leader psychology. Realism, with its emphasis
on raison d'etat, combined with scientism, with its envy of the natural
law explanations of physics and the seeming powerfulness of economic
models, provided a denatured perspective of international politics. It is not
difficult to see how game theoretic and rational choice analyses could therefore
be constructed as the most useful approaches to the study of international
relations. It is not coincidental that the development of this "states
systemic project" took place during the Cold War, which could be viewed as
the natural crucible for its development. This project emphasized
the importance ofsystem-level explanations ofstate behavior, at the
expense of examining more micro-level explanatory levels that focus on how
and why individuals act in international relations.