The relationship between state behavior and system behavior has occupied the attention of scholars and practitioners of international politics for hundreds of years. The predominant assumption of state behavior is that states act in their self-interest; this is their best guarantee of survival in an anarchic world. But most observers feel that system equilibrium is not possible in a world of such states; some additional element is necessary to preserve the main characteristics of the system. In this paper, a computer simulation is used to investigate (a) whether in a world of self-interested states, system-level behavior that acts to preserve or restore equilibrium will emerge, and (b) whether this is sufficient to preserve most of the actors in the system.