Structural Realism after the Cold War

Abstract

Some students of international politics believe that realism is obsolete.1 They argue that, although realism’s concepts of anarchy, self-help, and power balancing may have been appropriate to a bygone era, they have been displaced by changed conditions and eclipsed by better ideas. New times call for new thinking. Changing conditions require revised theories or entirely different ones. True, if the conditions that a theory contemplated have changed, the theory no longer applies. But what sorts of changes would alter the international political system so profoundly that old ways of thinking would no longer be relevant? Changes of the system would do it; changes in the system would not. Within-system changes take place all the time, some important, some not. Big changes in the means of transportation, communication, and war Žghting, for example, strongly affect how states and other agents interact. Such changes occur at the unit level. In modern history, or perhaps in all of history, the introduction of nuclear weaponry was the greatest of such changes. Yet in the nuclear era, international politics remains a self-help arena. Nuclear weapons decisively change how some states provide for their own and possibly for others’ security; but nuclear weapons have not altered the anarchic structure of the international political system. Changes in the structure of the system are distinct from changes at the unit level. Thus, changes in polarity also affect how states provide for their security. SigniŽcant changes take place when the number of great powers reduces to two or one. With more than two, states rely for their security both on their