  The new debate between international (neo)realists and (neo)liberals is no longer concerned with the questions of morality and human nature, but with the extent to which state behavior is influenced by the anarchic structure of the international system rather than by institutions, learning and other factors that are conductive to cooperation. In his 1989 book International Institutions and State Power, Robert Keohane accepts Waltz’s emphasis on system-level theory and his general assumption that states are self-interested actors that rationally pursue their goals. However, by employing game theory he shows that states can widen the perception of their self-interest through economic cooperation and involvement in international institutions. Patterns of interdependence can thus affect world politics. Keohane calls for systemic theories that would be able to deal better with factors affecting state interaction, and with change.