While American military muscle gives it superiority in the top tier, its global hegemony is contested in the second tier by Europe and Japan, whose contribution to world product is considered significant, and by non-state actors and phenomena (including terrorist organisations, viruses, and financial flows) from all states within the system, in the bottom tier. This liberal interpretation of world politics is both refreshing and enlightening. It questions the ability of the United States to act unilaterally, and furthermore impinges upon the presumption of states as the sole actors in the global arena and the efficacy of the realist interpretation in determining the prospective behaviour of these units.
US Hegemony promotes peace.
To expound the notion that unipolarity, contrary to popular belief, is neither unstable nor dangerous, it can be stated from the realist presumptions that states are motivated in their actions by the potential for either enhanced security or power, or both. From this initial postulation, the theories of hegemony and balance of power can be used to reveal that states will eschew action that undermines the status quo. Why then, has there been a trend towards co-operation? Ambiguity generates hegemonic rivalry due to disagreement over relative power, and logically therefore the asymmetry of the United States power portfolio eliminates ambiguity regarding states relative capabilities. In addition, it is unfeasible for other states to balance, due to prohibitive costs in doing so, and the "check" that regional powers provide before aspirants develop into a direct threat to the US's sole pole status. It is in America's interest to act in a manner that minimises security competition, of which the "system creates demand". This does not mean states will not engage in conflict with each other in order to gain entry into the set of great powers, but that they will fail to restructure the system.
