ABSTRACT
The Soviet Union's collapse in 1991 transformed the bipolar Cold War international system into a unipolar system dominated by the United States. During the past two decades, the goal of each US president from George H.W. Bush to Barack Obama has been to maintain the United States' preponderant power in a unipolar international order – the Pax Americana. Until recently, the conventional wisdom among the US foreign policy establishment has been that the Pax Americana would last well into the future. Partly as a result of the global economic meltdown that began in fall 2007, however, the question of unipolarity's longevity has become a topic of intensifying debate in the United States, to which Fareed Zakaria's widely discussed 2009 book, The Post-American World, is considered to be a major contribution.
