In this study we probe whether a simple model of reciprocity adequately describes superpower foreign policy interactions. We employ structural equation tests to detect the presence of “reciprocity” in conflict and cooperation among the dyadic relations of the United States, the Soviet Union, and the People's Republic of China. While these tests did not confirm the existence of consistent reciprocity in superpower relations, cointegration tests uniformly suggest that foreign policy behavior among the superpowers is characterized by trend components which move together via an “error correction” mechanism. This, in turn, suggests that equilibria levels of cooperation and conflict exist which explain much of superpower foreign-policy behavior. We hypothesize that over the course of the last four decades reactivity among superpowers has been generally weak, but that stronger periods of short-term reactivity in the 1950s created norms. We argue that reactivity has declined in the period since the creation of these norms. Thus, it would appear that reciprocity in superpower interactions is more complicated than typically portrayed in the international relations literature.