Unipolarity: A Structural Perspective
To say that the world is now unipolar is neither to praise American power, let alone its leadership, nor to accuse the United States of having established a worldwide empire. It is to state a fact, but one whose meaning is far from clear, as we have neither a powerful theory nor much evidence about how unipolar systems operate. A central diffi- culty for sorting this out entails determining the extent to which behav- ior and outcomes we have seen stem from structure, rather than from other levels of analysis, such as idiosyncratic aspects of the international environment, the American domestic system, and the role of individual leaders. How might the system function if the unipole were Nazi Ger- many, Stalin’s USSR (or Brezhnev’s), or a traditional autocracy? Or if it were the United States in a different era? There would surely be major differences, but we should still start our analysis with structure. In fact, this takes us quite far and, as well, to some unexpected places. Realism indicates that the unipole is likely to be difficult to restrain, no matter how benign its intentions or domestic regime. Furthermore, it is far from clear that it should seek to maintain existing arrangements. Both normal ambitions and, in the current context, American values and be- liefs may lead the superpower to seek to change the system rather than preserve it.