William C. Wohlforth is Assistant Professor of International Relations in the Edmund A. Walsh School of Foreign Service at Georgetown University.
I am indebted to Stephen G. Brooks, Charles A. Kupchan, Joseph Lepgold, Robert Lieber, and Kathleen R. McNamara, who read and commented on drafts of this article.
1. Charles Krauthammer, "The Unipolar Moment," Foreign Affairs, Vol. 70, No. 1 (Winter 1990/1991), pp. 23-33.
2. Patrick Tyler, "The Lone Superpower Plan: Ammunition for Critics," New York Times, March 10, 1992, p. A12.
3. For the most thorough and theoretically grounded criticism of this strategy, see Christopher Layne, "The Unipolar Illusion: Why New Great Powers Will Arise," International Security, Vol. 17, No. 4 (Spring 1993), pp. 5-51; and Layne, "From Preponderance to Offshore Balancing: America's Future Grand Strategy," International Security, Vol. 22, No. 1 (Summer 1997), pp. 86-124.
4. The phrase—commonly attributed to Secretary of State Madeleine Albright—is also a favorite of President Bill Clinton's. For example, see the account of his speech announcing the expansion of the North Atlantic Treaty Organization in Alison Mitchell, "Clinton Urges NATO Expansion in 1999," New York Times, October 23, 1996, p. A20.
5. Kenneth N. Waltz, "Evaluating Theories," American Political Science Review, Vol. 91, No. 4 (December 1997), pp. 915-916; Layne, "Unipolar Illusion"; and Michael Mastanduno, "Preserving the Unipolar Moment: Realist Theories and U.S. Grand Strategy after the Cold War," International Security, Vol. 21, No. 4 (Spring 1997), pp. 44-98. Although I differ with Waltz on the stability of unipolarity, the title of this article and much of its contents reflect intellectual debts to his work on system structure and stability. See Waltz, "The Stability of a Bipolar World," Daedalus, Vol. 93, No. 3 (Summer 1964), pp. 881-901.
6. See Charles A. Kupchan, "After Pax Americana: Benign Power, Regional Integration, and the Sources of Stable Multipolarity," International Security, Vol. 23, No. 3 (Fall 1998), pp. 40-79. Samuel P. Huntington maintained this position in Huntington, "Why International Primacy Matters," International Security, Vol. 17, No. 4 (Spring 1993), pp. 63-83, but he has since abandoned it. A more bullish assessment, although still more pessimistic than the analysis here, is Douglas Lemke, "Continuity of History: Power Transition Theory and the End of the Cold War," Journal of Peace Research, Vol. 34, No. 1 (February 1996), pp. 203-236.
7. As Glenn H. Snyder puts it, the international system "appears to be unipolar, though incipiently multipolar." Snyder, Alliance Politics (Ithaca, N.Y.: Cornell University Press, 1997), p. 18. The quoted phrases in this sentence appear in Charles A. Kupchan, "Rethinking Europe," National Interest, No. 56 (Summer 1999); Kupchan, "After Pax Americana," p. 41; Layne, "Unipolar Illusion"; Mastanduno, "Preserving the Unipolar Moment"; and Waltz, "Evaluating Theories," p. 914. Although Charles Krauthammer coined the term "unipolar moment" in his article under that title, he argued that unipolarity had the potential to last a generation.
8. Samuel P. Huntington, "The Lonely Superpower," Foreign Affairs, Vol. 78, No. 2 (March/April 1999), p. 36. For similar views of the post-Cold War structure, see Aaron L. Friedberg, "Ripe for Rivalry: Prospects for Peace in a Multipolar Asia," International Security, Vol. 18, No. 3 (Winter 1993/94), pp. 5-33; and Josef Joffe, "'Bismarck' or 'Britain'? Toward an American Grand Strategy after Bipolarity," International Security, Vol. 19, No. 4 (Spring 1995), pp. 94-117.
9. The assumption that realism predicts instability after the Cold War pervades the scholarly debate. See, for example, Sean M. Lynn-Jones and Steven E. Miller, eds., The Cold War and After: Prospects for Peace—An International Security Reader (Cambridge, Mass.: MIT Press, 1993); and David A. Baldwin, ed., Neorealism and Neoliberalism: The Contemporary Debate (New York: Columbia University Press, 1993). For more varied perspectives on realism and unipolarity, see Ethan B. Kapstein and Michael Mastanduno, eds., Unipolar Politics: Realism and State Strategies after the Cold War (New York: Columbia University Press, 1999). Explanations for stability despite the balance of power fall roughly into three categories: (1) liberal arguments, including democratization, economic interdependence, and international institutions. For examples, see Bruce M. Russett, Grasping the Democratic Peace (Princeton, N.J.: Princeton University...