A bold and elegant new statement about the coming breakdown of Pax Americana and a return to great-power rivalry. The United States is so powerful that it looks as though a Washington-centered international order will last forever. In this thought-provoking study, however, Kupchan argues that a unipolar world is unsustainable. Dramatic shifts in the international landscape are afoot -- and America neglects this emerging unfavorable turn of events at its own peril. In Kupchan's view, two developments are pushing the world back to multipolarity. One is the rise of Europe, which is acquiring both the economic and political heft necessary to challenge American leadership and its own political identity as a superpower. The other is the decline of American public support for internationalism, which makes it increasingly difficult for the United States to honor commitments and bear the burdens of sustaining the existing order. Indeed, Kupchan is most insightful in illuminating the impact of America's distinctive political culture on grand strategy. In his eyes, the growing influence of the old-style populism found in the American South and West -- and its deep suspicion of international engagement and entanglements -- will fuel the American retreat from the global stage. Eventually, the end of U.S. primacy will usher in a more "unpredictable and unpleasant" world of competition and conflict between the traditional great powers. But Kupchan is vague about how dangerous or unstable this order will be. He rejects the predictions of both realist hard-liners, who expect rivalry and the threat of war, and liberal optimists, who expect an expanding democratic peace. Rather, Kupchan thinks the coming order will be marked by a return to the familiar world of competing great powers but also by the revolutionary changes of a new digital era. The book's message to the navigators of the American ship of state: open your eyes and expect change ahead.