More than a decade ago, political columnist Charles Krauthammer proclaimed in these pages the arrival of what he called a "unipolar moment," a period in which one superpower, the United States, stood clearly above the rest of the international community ("The Unipolar Moment," America and the World 1990/91). In the following years the Soviet Union collapsed, Russia's economic and military decline accelerated, and Japan stagnated, while the United States experienced the longest and one of the most vigorous economic expansions in its history. Yet toward the close of the century readers could find political scientist Samuel Huntington arguing here that unipolarity had already given way to a "uni-multipolar" structure, which in turn would soon become unambiguously multipolar ("The Lonely Superpower," March/April 1999). And despite the boasting rhetoric of American officials, Huntington was not alone in his views. Polls showed that more than 40 percent of Americans had come to agree that the United States was now merely one of several leading powers -- a number that had risen steadily for several years.

Why did the unipolarity argument seem less persuasive to many even as U.S. power appeared to grow? Largely because the goal posts were moved. Krauthammer's definition of unipolarity, as a system with only one pole, made sense in the immediate wake of a Cold War that had been so clearly shaped by the existence of two poles. People sensed intuitively that a world with no great power capable of sustaining a focused rivalry with the United States would be very different in important ways.

But a decade later what increasingly seemed salient was less the absence of a peer rival than the persistence of a number of problems in the world that Washington could not dispose of by itself. This was the context for Huntington's new definition of unipolarity, as a system with "one superpower, no significant major powers, and many minor powers." The dominant power in such a system, he argued, would be able to "effectively resolve important international issues alone, and no combination of other states would have the power to prevent it from doing so." The United States had no such ability and thus did not qualify.

The terrorist attacks last fall appeared to some to reinforce this point, revealing not only a remarkable degree of American vulnerability but also a deep vein of global anti-American resentment. Suddenly the world seemed a more threatening place, with dangers lurking at every corner and eternal vigilance the price of liberty. Yet as the success of the military campaign in Afghanistan demonstrated, vulnerability to terror has few effects on U.S. strength in more traditional interstate affairs. If anything, America's response to the attacks -- which showed its ability to project power in several places around the globe simultaneously, and essentially unilaterally, while effortlessly increasing defense spending by nearly $50 billion -- only reinforced its unique position.

If today's American primacy does not constitute unipolarity, then nothing ever will. The only things left for dispute are how long it will last and what the implications are for American foreign policy.


To understand just how dominant the United States is today, one needs to look at each of the standard components of national power in succession. In the military arena, the United States is poised to spend more on defense in 2003 than the next 15-20 biggest spenders combined. The United States has overwhelming nuclear superiority, the world's dominant air force, the only truly blue-water navy, and a unique capability to project power around the globe. And its military advantage is even more apparent in quality than in quantity. The United States leads the world in exploiting the military applications of advanced communications and information technology and it has demonstrated an unrivaled ability to coordinate and process information about the battlefield and destroy targets from afar with extraordinary precision. Washington is not making it easy for others to catch up, moreover, given the massive gap in spending on military research and development (R&D), on which the United States spends three times more than the next six powers combined. Looked at another way, the United States currently spends more on military R&D than Germany or the United Kingdom spends on defense in total.

No state in the modern history of international politics has come close to the military predominance these numbers suggest. And the United States purchases this preeminence with only 3.5 percent of its GDP. As historian Paul Kennedy notes, "being Number One at great cost is one thing; being the world's single superpower on the cheap is astonishing."

America's economic dominance, meanwhile -- relative to either the next several richest powers or the rest of the world combined -- surpasses that of any great power in modern history, with the sole exception of its own position after 1945 (when World War II had temporarily laid waste every other major economy). The U.S. economy is currently twice as large as its closest rival, Japan. California's economy alone has risen to become the fifth largest in the world (using market exchange-rate estimates), ahead of France and just behind the United Kingdom.

It is true that the long expansion of the 1990s has ebbed, but it would take an experience like Japan's in that decade -- that is, an extraordinarily deep and prolonged domestic recession juxtaposed with robust growth elsewhere -- for the United States just to fall back to the economic position it occupied in 1991. The odds against such relative decline are long, however, in part because the United States is the country in the best position to take advantage of globalization. Its status as the preferred destination for scientifically trained foreign workers solidified during the 1990s, and it is the most popular destination for foreign firms. In 1999 it attracted more than one-third of world inflows of foreign direct investment.

U.S. military and economic dominance, finally, is rooted in the country's position as the world's leading technological power. Although measuring national R&D spending is increasingly difficult in an era in which so many economic activities cross borders, efforts to do so indicate America's continuing lead. Figures from the late 1990s showed that U.S. expenditures on R&D nearly equaled those of the next seven richest countries combined.

Measuring the degree of American dominance in each category begins to place things in perspective. But what truly distinguishes the current international system is American dominance in all of them simultaneously. Previous leading states in the modern era were either great commercial and naval powers or great military powers on land, never both. The British Empire in its heyday and the United States during the Cold War, for example, each shared the world with other powers that matched or exceeded them in some areas. Following the Napoleonic Wars, the United Kingdom was clearly the world's leading commercial and naval power. But even at the height of the Pax Britannica, the United Kingdom was outspent, outmanned, and outgunned by both France and Russia. And its 24 percent share of GDP among the six leading powers in the early 1870s was matched by the United States, with Russia and Germany following close behind. Similarly, at the dawn of the Cold War the United States was clearly dominant economically as well as in air and naval capabilities. But the Soviet Union retained overall military parity, and thanks to geography and investment in land power it had a superior ability to seize territory in Eurasia.

Today, in contrast, the United States has no rival in any critical dimension of power. There has never been a system of sovereign states that contained one state with this degree of dominance. The recent tendency to equate unipolarity with the ability to achieve desired outcomes single-handedly on all issues only reinforces this point; in no previous international system would it ever have occurred to anyone to apply such a yardstick.


Many who acknowledge the extent of American power, however, regard it as necessarily self-negating. Other states traditionally band together to restrain potential hegemons, they say, and this time will be no different. As German political commentator Josef Joffe has put it, "the history books say that Mr. Big always invites his own demise. Nos. 2, 3, 4 will gang up on him, form countervailing alliances and plot his downfall. That happened to Napoleon, as it happened to Louis xiv and the mighty Hapsburgs, to Hitler and to Stalin. Power begets superior counterpower; it's the oldest rule of world politics."

What such arguments fail to recognize are the features of America's post-Cold War position that make it likely to buck the historical trend. Bounded by oceans to the east and west and weak, friendly powers to the north and south, the United States is both less vulnerable than previous aspiring hegemons and also less threatening to others. The main potential challengers to its unipolarity, meanwhile -- China, Russia, Japan, and Germany -- are in the opposite position. They cannot augment their military capabilities so as to balance the United States without simultaneously becoming an immediate threat to their neighbors. Politics, even international politics, is local. Although American power attracts a lot of attention globally, states are usually more concerned with their own neighborhoods than with the global equilibrium. Were any of the potential challengers to make a serious run at the United States, regional balancing efforts would almost certainly help contain them, as would the massive latent power capabilities of the United States, which could be mobilized as necessary to head off an emerging threat.

When analysts refer to a historical pattern of balancing against potentially preponderant powers, they rarely note that the cases in question -- the Hapsburg ascendancy, Napoleonic France, the Soviet Union in the Cold War, and so forth -- featured would-be hegemons that were vulnerable, threatening, centrally located, and dominant in only one or two components of power. Moreover, the would-be hegemons all specialized in precisely the form of power -- the ability to seize territory -- most likely to scare other states into an antihegemonic coalition. American capabilities, by contrast, are relatively greater and more comprehensive than those of past hegemonic aspirants, they are located safely offshore, and the prospective balancers are close regional neighbors of one another. U.S. power is also at the command of one government, whereas the putative balancers would face major challenges in acting collectively to assemble and coordinate their military capabilities.

Previous historical experiences of balancing, moreover, involved groups of status quo powers seeking to contain a rising revisionist one. The balancers had much to fear if the aspiring hegemon got its way. Today, however, U.S. dominance is the status quo. Several of the major powers in the system have been closely allied with the United States for decades and derive substantial benefits from their position. Not only would they have to forego those benefits if they tried to balance, but they would have to find some way of putting together a durable, coherent alliance while America was watching. This is a profoundly important point, because although there may be several precedents for a coalition of balancers preventing a hegemon from emerging, there is none for a group of subordinate powers joining to topple a hegemon once it has already emerged, which is what would have to happen today.

The comprehensive nature of U.S. power, finally, also skews the odds against any major attempt at balancing, let alone a successful one. The United States is both big and rich, whereas the potential challengers are all either one or the other. It will take at least a generation for today's other big countries (such as China and India) to become rich, and given declining birth rates the other rich powers are not about to get big, at least in relative terms. During the 1990s, the U.S. population increased by 32.7 million -- a figure equal to more than half the current population of France or the United Kingdom.

Some might argue that the European Union is an exception to the big-or-rich rule. It is true that if Brussels were to develop impressive military capabilities and wield its latent collective power like a state, the EU would clearly constitute another pole. But the creation of an autonomous and unified defense and defense-industrial capacity that could compete with that of the United States would be a gargantuan task. The EU is struggling to put together a 60,000-strong rapid reaction force that is designed for smaller operations such as humanitarian relief, peacekeeping, and crisis management, but it still lacks military essentials such as capabilities in intelligence gathering, airlift, air-defense suppression, air-to-air refueling, sea transport, medical care, and combat search and rescue -- and even when it has those capacities, perhaps by the end of this decade, it will still rely on NATO command and control and other assets.

Whatever capability the EU eventually assembles, moreover, will matter only to the extent that it is under the control of a statelike decision-making body with the authority to act quickly and decisively in Europe's name. Such authority, which does not yet exist even for international financial matters, could be purchased only at the price of a direct frontal assault on European nations' core sovereignty. And all of this would have to occur as the EU expands to add ten or more new member states, a process that will complicate further deepening. Given these obstacles, Europe is unlikely to emerge as a dominant actor in the military realm for a very long time, if ever.

Most analysts looking for a future peer competitor to the United States, therefore, focus on China, since it is the only power with the potential to match the size of the U.S. economy over the next several decades. Yet even if China were eventually to catch up to the United States in terms of aggregate GDP, the gaps in the two states' other power capabilities -- technological, military, and geographic -- would remain.

Since the mid-1990s, Chinese strategists themselves have become markedly less bullish about their country's ability to close the gap in what they call "comprehensive national power" any time soon. The latest estimates by China's intelligence agency project that in 2020 the country will possess between slightly more than a third and slightly more than half of U.S. capabilities. Fifty percent of China's labor force is employed in agriculture, and relatively little of its economy is geared toward high technology. In the 1990s, U.S. spending on technological development was more than 20 times China's. Most of China's weapons are decades old. And nothing China can do will allow it to escape its geography, which leaves it surrounded by countries that have the motivation and ability to engage in balancing of their own should China start to build up an expansive military force.

These are not just facts about the current system; they are recognized as such by the major players involved. As a result, no global challenge to the United States is likely to emerge for the foreseeable future. No country, or group of countries, wants to maneuver itself into a situation in which it will have to contend with the focused enmity of the United States.

Two of the prime causes of past great-power conflicts -- hegemonic rivalry and misperception -- are thus not currently operative in world politics. At the dawn of the twentieth century, a militarily powerful Germany challenged the United Kingdom's claim to leadership. The result was World War I. In the middle of the twentieth century, American leadership seemed under challenge by a militarily and ideologically strong Soviet Union. The result was the Cold War. U.S. dominance today militates against a comparable challenge, however, and hence against a comparable global conflict. Because the United States is too powerful to balance, moreover, there is far less danger of war emerging from the misperceptions, miscalculations, arms races, and so forth that have traditionally plagued balancing attempts. Pundits often lament the absence of a post-Cold War Bismarck. Luckily, as long as unipolarity lasts, there is no need for one.


The conclusion that balancing is not in the cards may strike many as questionable in light of the parade of ostensibly anti-U.S. diplomatic combinations in recent years: the "European troika" of France, Germany, and Russia; the "special relationship" between Germany and Russia; the "strategic triangle" of Russia, China, and India; the "strategic partnership" between China and Russia; and so on. Yet a close look at any of these arrangements reveals their rhetorical as opposed to substantive character. Real balancing involves real economic and political costs, which neither Russia, nor China, nor indeed any other major power has shown any willingness to bear.

The most reliable way to balance power is to increase defense outlays. Since 1995, however, military spending by most major powers has been declining relative to GDP, and in the majority of cases in absolute terms as well. At most, these opposing coalitions can occasionally succeed in frustrating U.S. policy initiatives when the expected costs of doing so remain conveniently low. At the same time, Beijing, Moscow, and others have demonstrated a willingness to cooperate with the United States periodically on strategic matters and especially in the economic realm. This general tendency toward bandwagoning was the norm before September 11 and has only become more pronounced since then.

Consider the Sino-Russian "strategic partnership," the most prominent instance of apparent balancing to date. The easy retort to overheated rhetoric about a Moscow-Beijing "axis" would involve pointing out how it failed to slow, much less stop, President Vladimir Putin's geopolitical sprint toward Washington in the aftermath of the September 11 attacks. More telling, however, is just how tenuous the shift was even before it was thrown off track. At no point did the partnership entail any costly commitment or policy coordination against Washington that might have risked a genuine confrontation. The keystone of the partnership -- Russia's arms sales to China -- reflects a symmetry of weaknesses, rather than the potential of combined strengths. The sales partially offset China's backward military technology while helping to slow the decline of Russia's defense industries. Most of the arms in question are legacies of the R&D efforts of the Soviet military-industrial complex, and given Moscow's paltry R&D budget today, few of these systems will long remain competitive with their U.S. or NATO analogues.

Even as the two neighbors signed cooperative agreements, moreover, deep suspicions continued to plague their relationship, economic ties between them remained anemic and unlikely to grow dramatically, and both were highly dependent on inflows of capital and technology that could come only from the West. Russian and Chinese leaders highlighted their desire for a world of reduced U.S. influence not because this was a goal toward which they had actually started moving, but because it was one general principle on which they could agree.

Balancing rhetoric is obviously partly the reflection of genuine sentiment. The world finds it unfair, undemocratic, annoying, and sometimes downright frightening to have so much power concentrated in the hands of one state, especially when the United States aggressively goes its own way. But given the weight and prominence of U.S. power on the world stage, some unease among other countries is inevitable no matter what Washington does. Foreign governments frequently rail against what they regard as excessive U.S. involvement in their affairs. Yet inflated expectations about what the United States can do to solve global problems (such as the Israeli-Palestinian conflict) can lead to frustration with supposed U.S. underengagement as well. Nothing the United States could do short of abdicating its power would solve the problem completely.

Local and regional politics also contribute to balancing rhetoric, although not to its substance. Even nondemagogic leaders face incentives to play on anti-American resentment for domestic audiences. And simple math dictates the need for more regional cooperation today than previously, much of which can take on an anti-American coloring. The nineteenth-century international system featured six to eight poles among roughly 30 states. In the early Cold War, there were two poles, but the number of states had doubled to just over 70. Today there is one pole in a system in which the population has trebled to nearly 200. Inevitably, therefore, much activity will take place at a regional level, and it can often be in the interests of the parties involved to use balancing rhetoric as a rallying point for stimulating cooperation, even if that is not the chief driver of their actions.

Such maneuvering has the potential to backfire, however, by reinforcing the perception that the countries in question are too weak to act individually, something that can have harmful consequences at home and abroad. Thus, other powers have to find a way of reminding Washington that they have somewhere else to turn, but without talking down their own capabilities or foreclosing promising bilateral arrangements with the United States. The result -- balancing that is rhetorically grand but substantively weak -- is politics as usual in a unipolar world.


The first and most important practical consequence of unipolarity for the United States is notable for its absence: the lack of hegemonic rivalry. During the Cold War the United States confronted a military superpower with the potential to conquer all the industrial power centers of Europe and Asia. To forestall that catastrophic outcome, for decades the United States committed between 5 and 14 percent of its GDP to defense spending and maintained an extended nuclear deterrent that put a premium on the credibility of its commitments. Largely to maintain a reputation for resolve, 85,000 Americans lost their lives in two Asian wars while U.S. presidents repeatedly engaged in brinkmanship that ran the risk of escalation to global thermonuclear destruction.

Today the costs and dangers of the Cold War have faded into history, but they need to be kept in mind in order to assess unipolarity accurately. For decades to come, no state is likely to combine the resources, geography, and growth rates necessary to mount a hegemonic challenge on such a scale -- an astonishing development. Crowns may generally lie uneasy, but America's does not.

Some might question the worth of being at the top of a unipolar system if that means serving as a lightning rod for the world's malcontents. When there was a Soviet Union, after all, it bore the brunt of Osama bin Laden's anger, and only after its collapse did he shift his focus to the United States (an indicator of the demise of bipolarity that was ignored at the time but looms larger in retrospect). But terrorism has been a perennial problem in history, and multipolarity did not save the leaders of several great powers from assassination by anarchists around the turn of the twentieth century. In fact, a slide back toward multipolarity would actually be the worst of all worlds for the United States. In such a scenario it would continue to lead the pack and serve as a focal point for resentment and hatred by both state and nonstate actors, but it would have fewer carrots and sticks to use in dealing with the situation. The threats would remain, but the possibility of effective and coordinated action against them would be reduced.

The second major practical consequence of unipolarity is the unique freedom it offers American policymakers. Many decisionmakers labor under feelings of constraint, and all participants in policy debates defend their preferred courses of action by pointing to the dire consequences that will follow if their advice is not accepted. But the sources of American strength are so varied and so durable that U.S. foreign policy today operates in the realm of choice rather than necessity to a greater degree than any other power in modern history. Whether the participants realize it or not, this new freedom to choose has transformed the debate over what the U.S. role in the world should be.

Historically, the major forces pushing powerful states toward restraint and magnanimity have been the limits of their strength and the fear of overextension and balancing. Great powers typically checked their ambitions and deferred to others not because they wanted to but because they had to in order to win the cooperation they needed to survive and prosper. It is thus no surprise that today's champions of American moderation and international benevolence stress the constraints on American power rather than the lack of them. Political scientist Joseph Nye, for example, insists that "[the term] unipolarity is misleading because it exaggerates the degree to which the United States is able to get the results it wants in some dimensions of world politics. ... American power is less effective than it might first appear." And he cautions that if the United States "handles its hard power in an overbearing, unilateral manner," then others might be provoked into forming a balancing coalition.

Such arguments are unpersuasive, however, because they fail to acknowledge the true nature of the current international system. The United States cannot be scared into meekness by warnings of inefficacy or potential balancing. Isolationists and aggressive unilateralists see this situation clearly, and their domestic opponents need to as well. Now and for the foreseeable future, the United States will have immense power resources it can bring to bear to force or entice others to do its bidding on a case-by-case basis.

But just because the United States is strong enough to act heedlessly does not mean that it should do so. Why not? Because it can afford to reap the greater gains that will eventually come from magnanimity. Aside from a few cases in a few issue areas, ignoring others' concerns avoids hassles today at the cost of more serious trouble tomorrow. Unilateralism may produce results in the short term, but it is apt to reduce the pool of voluntary help from other countries that the United States can draw on down the road, and thus in the end to make life more difficult rather than less. Unipolarity makes it possible to be the global bully -- but it also offers the United States the luxury of being able to look beyond its immediate needs to its own, and the world's, long-term interests.


Consider the question that preoccupied many observers before September 11: whether to engage or contain potential great-power challengers such as China. Supporters of engagement argued that the best way to moderate Chinese behavior (both internal and external) was to tie the country into the international political and economic system as thoroughly as possible. Supporters of containment, meanwhile, argued that this course was far too risky, because it might hasten the emergence of a strong but still tyrannical power. To the extent that the above analysis of unipolarity is correct, however, the risks that accompany engagement are minor, because the margin of U.S. superiority is so great that China is unlikely to pose a significant challenge to U.S. dominance for decades, no matter what policy is followed. Although engagement may not succeed, therefore, the chance that it might makes it worth a try, and there will be plenty of time to reverse course if it fails.

The same applies with even more force to Russia. The aftermath of the September 11 attacks demonstrated the benefits of having a stable friend in Eurasia's heartland, and the preceding three centuries demonstrated the high costs that could come from an autocratic Russia that is extracting military capabilities from its vast territory. Integrating Russia fully into the reigning international order would represent a major step toward eliminating the perennial "Russia problem." Russia's political and economic institutions have a long road to travel before such integration becomes feasible, of course, but thanks to unipolarity there is plenty of time to wait, and there are plenty of resources to deploy in helping.

Washington also needs to be concerned about the level of resentment that an aggressive unilateral course would engender among its major allies. After all, it is influence, not power, that is ultimately most valuable. The further one looks beyond the immediate short term, the clearer become the many issues -- the environment, disease, migration, and the stability of the global economy, to name a few -- that the United States cannot solve on its own. Such issues entail repeated dealings with many partners over many years. Straining relationships now will lead only to a more challenging policy environment later on.

As for the developing world, if the United States could help improve political, social, and economic conditions there, practically everybody would benefit -- the locals directly, and the rest of the world indirectly. No magic wand can transform the situation overnight, but the United States can nevertheless take a variety of measures that would help on the margins. The most important would be to lower the high protectionist trade barriers Washington maintains for agricultural products, clothing, and textiles -- all crucial for the economic prospects of much of the developing world. Opening up U.S. markets to developing-country exports in these areas would not guarantee rapid economic development abroad, and even if it did, rapid development is not a panacea for all ills. But there is little doubt that it would help the exporting countries' economies and societies along with America's image.

President George W. Bush recently said, "To be serious about fighting poverty, we must be serious about expanding trade.... Greater access to the markets of wealthy countries has a direct and immediate impact on the economies of developing nations." But deeds are more important than words. Lowering domestic trade barriers would be precisely the kind of U.S. policy that could reduce the inevitable frictions and resentments unipolarity generates. It would mean going beyond reacting to security challenges once they became critical and trying to forestall their emergence in the first place. Implemented fully and expanded to other cases, this approach could serve as the velvet glove covering the iron fist of American power, demonstrating that the United States was interested in not just its own special interests but the interests of others as well.

Magnanimity and restraint in the face of temptation are tenets of successful statecraft that have proved their worth from classical Greece onward. Standing taller than leading states of the past, the United States has unprecedented freedom to do as it pleases. It can play the game for itself alone or for the system as a whole; it can focus on small returns today or larger ones tomorrow. If the administration truly wants to be loved as well as feared, the policy answers are not hard to find.

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