Unipolarity and Its Consequences - Liberal Leviathan: The Origins, Crisis, and Transformation of the American World Order - page 91

because states such as China and Russia have established a nuclear deterrent, they do not
need to worry about war and domination by the leading state. American power is rendered
more tolerable because in the age of nuclear deterrence, American military power cannot
now be used for conquest against other great powers. Deterrence replaces alliance counter-
balancing. Second, nuclear weapons also make it harder for these great powers to overturn
the existing international order. The status quo international order led by the United States
is rendered less easily replaced. War-driven change is removed as a historical process. As
Robert Gilpin has noted, great-power war is precisely the mechanism of change that has been
used throughout history to redraw the international order. Rising states depose the reign-
ing—but declining—state and impose a new order. 19 Thus, there is a double effect of nuclear
weapons. The demand for great-power balancing declines in comparison to that in previous
eras. Likewise, the ability of a countercoalition—should it actually emerge—to overturn the
existing order through war also declines as an option. The overall effect is to undercut the
logic of great-power balancing.
Finally, world geography has also shaped the way American unipolar power is expressed.
The United States is the only great power that is not neighbored by other great powers.
This geographical remoteness made the power ascent of the United States less threatening to
the rest of the world. The United States could continue to grow without destabilizing great-
power relations. 20 America's era of territorial expansion took place without directly threat-
ening other major states. The European powers had stakes in the New World but not fun-
damental interests or even—at least by the mid-nineteenth century—a direct presence. The
United States purchased territory from France rather than acquiring it by conquest. Germany,
of course, was not as geographically lucky, and the expansion and unification of Germany
unleashed nationalist rivalries, territorial ambitions, arms races, and ultimately world war. 21
As European great powers grew in strength, they tended to trigger security-dilemma-driven
conflict and balancing reactions in their regional neighborhoods. But America's remoteness
lessened the destabilizing impact of its transition to global prominence. 22
The geographical remoteness of American power has made it less threatening to other
states—something that mattered both during the bipolar Cold War era and under the current
conditions of unipolarity. In addition, the way that unipolarity emerged softened its impact
on great-power calculations. The United States did not become unipolar through a war, and
certainly not through a war of territorial aggression. It became unipolar when its bipolar rival
collapsed. Unipolarity emerged quietly as the Soviet system fell into disarray and as Western
Europe and Japan grew more slowly than the United States and remained closely allied with
it.