During the second half of the 1980s, the United States went through one of its periodic bouts of declinism. Paul Kennedy's 1987 bestseller The Rise and Fall of the Great Powers concluded with a chapter on Washington's "relative decline," arguing that the United States was a victim of "imperial overstretch" because "the sum total of [its] global interests and obligations is nowadays far larger than the country's power to defend them all simultaneously." This sparked heated responses and defenses from various quarters until the debate ended with the collapse of not the American empire, but its Soviet counterpart. In the two decades since, another intellectual cycle has run its course, with portraits of U.S. primacy giving way to another round of declinism. Different takes on this issue lead to different policy recommendations, so the debate cannot be ignored. But whether current entries will hold up longer than their predecessors remains an open question.

"The Unipolar Moment." By Charles Krauthammer. Foreign Affairs 70, no. 1 (1990/1991): pp. 23-33.
"The Stability of a Unipolar World." By William C. Wohlforth. International Security 24, no. 1 (1999): pp. 5-41.
As the Cold War era came to a close, Charles Krauthammer announced the arrival of its successor. The United States was the preeminent power in the world, he wrote, but it needed to exercise global leadership to maintain its position. The most compelling analysis of unipolarity was ultimately offered by William Wohlforth, who argued that the United States possessed a commanding lead in four critical elements of material power: economic strength, military might, technology, and geography. The combination meant that the United States was not only dominant but so strong that other powers had no chance of catching up anytime soon no matter what they did. As a result, Wohlforth claimed, U.S. primacy would not fade quickly but last for decades to come.

"The Unipolar Illusion: Why New Great Powers Will Rise." By Christopher Layne. International Security 17, no. 4 (1993): pp. 5-51.
"The Unipolar Illusion Revisited: The Coming End of the United States' Unipolar Moment." By Christopher Layne. International Security 31, no. 2 (2006): pp. 7-41.
Some academic realists, in contrast, expected unipolarity to fade relatively quickly, as self-interest led other powers to balance against the United States. Echoing Kennedy's 1987 book, Christopher Layne's 1993 article focused on the decline of the two most dominant powers prior to the United States -- France in the late seventeenth century and the United Kingdom in the nineteenth. Their rivals took advantage of tectonic economic shifts, adopted administrative and military innovations to accelerate their ascent, and joined alliances to check the hegemon. Something similar would happen soon, Layne argued, predicting that unipolarity would "give way to multipolarity between 2000-2010." Tackling the subject again near the end of that time frame, Layne acknowledged that U.S. power still reigned supreme. But he disputed claims that U.S. hegemony was somehow immune to realist laws of gravity and concluded that Washington should adopt a restrained "off-shore balancing" strategy rather than waste its power on self-defeating efforts to dominate the globe.

"Soft Balancing against the United States." By Robert A. Pape; "Soft Balancing in the Age of U.S. Primacy." By T. V. Paul; "Hard Times for Soft Balancing." By Stephen G. Brooks and William C. Wohlforth; and "Waiting for Balancing: Why the World Is Not Pushing Back." By Kier A. Lieber and Gerard Alexander. International Security 30, no. 1 (Summer 2005): pp. 7-139.

Old-school realists predicted that other states would move to counter U.S. primacy by banding together and expanding their militaries. Such "hard" balancing is barely noticeable, however. Some scholars, reluctant to accept that U.S. hegemony is unchallenged, have therefore come up with the new concept of "soft" balancing -- nonmilitary efforts by other countries to frustrate American adventurism, such as refusing active support, denying access to bases or airspace, and opposing the United States in international institutions. The articles in this symposium lay out the debate over whether such behavior is designed to constrain U.S. power and foreshadows more hard balancing to come or is simply routine politics in a unipolar world.

The Post-American World. By Fareed Zakaria. W. W. Norton, 2008.
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The United States may indeed be losing ground relative to other countries, argues Fareed Zakaria in this nuanced and highly readable book, but that has less to do with its own absolute decline than with "the rise of the rest." The real story of the age is economic growth across the developing world, which Americans should welcome rather than fear -- not least because of its promise for social and political liberalization abroad. The real challenge for the United States, Zakaria argues, will be getting its own economic and political house in order -- dealing with its many domestic problems so that its strengths in higher education and research and development, along with its demographic vitality and diversity, can sustain U.S. leadership in the global economy in the decades to come.

"International Primacy: Is the Game Worth the Candle?" By Robert Jervis. International Security 17, no. 4 (Spring 1993): pp. 52-67.
"Why International Primacy Matters." By Samuel P. Huntington. International Security 17, no. 4 (Spring 1993): pp. 68-83.

What's so great about primacy anyway? Political-science heavyweights Robert Jervis and Samuel Huntington squared off over this issue in the early 1990s, back when Japan was seen as the rising challenger. Jervis argues that the remote likelihood of great-power war makes military supremacy less essential for security today than in the past, and questions whether the United States needs primacy to promote its other goals. Huntington contends that in a dog-eat-dog world, U.S. primacy is an unalloyed good not only for the United States but for most weaker powers as well. Although the specter of Japanese economic competition has long since receded, the fundamental questions raised by Jervis and Huntington continue to inform the primacy debate.


  • PETER LIBERMAN is Professor of Political Science at Queens College and the Graduate Center of the City University of New York.
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