Introduction

Many in the West seem to believe that "perpetual peace" among the great powers is finally at hand. The end of the Cold War, so the argument goes, marked a sea change in how great powers interact with one another. We have entered a world in which there is little chance that the major powers will engage each other in security competition, much less war, which has become an obsolescent enterprise. In the words of one famous author, the end of the Cold War has brought us to the "the end of history."

    This perspective suggests that great powers no longer view each other as potential military rivals, but instead as members of a family of nations, members of what is sometimes called the "international community." The prospects for cooperation are abundant in this promising new world, a world which is likely to bring increased prosperity and peace to all the great powers. Even a few adherents of realism, a school of thought that has historically held pessimistic views about the prospects for peace among the great powers, appear to have bought into the reigning optimism, as reflected in an article from the mid-1990s titled "Realists as Optimists."

    Alas, the claim that security competition and war between the great powers have been purged from the international system is wrong. Indeed, there is much evidence that the promise of everlasting peace among the great powers was stillborn. Consider, for example, that even though the Soviet threat has disappeared, the United States stillmaintains about one hundred thousand troops in Europe and roughly the same number in Northeast Asia. It does so because it recognizes that dangerous rivalries would probably emerge among the major powers in these regions if U.S. troops were withdrawn. Moreover, almost every European state, including the United Kingdom and France, still harbors deep-seated, albeit muted, fears that a Germany unchecked by American power might behave aggressively; fear of Japan in Northeast Asia is probably even more profound, and it is certainly more frequently expressed. Finally, the possibility of a clash between China and the United States over Taiwan is hardly remote. This is not to say that such a war is likely, but the possibility reminds us that the threat of great-power war has not disappeared.

    The sad fact is that international politics has always been a ruthless and dangerous business, and it is likely to remain that way. Although the intensity of their competition waxes and wanes, great powers fear each other and always compete with each other for power. The overriding goal of each state is to maximize its share of world power, which means gaining power at the expense of other states. But great powers do not merely strive to be the strongest of all the great powers, although that is a welcome outcome. Their ultimate aim is to be the hegemon—that is, the only great power in the system.

    There are no status quo powers in the international system, save for the occasional hegemon that wants to maintain its dominating position over potential rivals. Great powers are rarely content with the current distribution of power; on the contrary, they face a constant incentive to change it in their favor. They almost always have revisionist intentions, and they will use force to alter the balance of power if they think it can be done at a reasonable price. At times, the costs and risks of trying to shift the balance of power are too great, forcing great powers to wait for more favorable circumstances. But the desire for more power does not go away, unless a state achieves the ultimate goal of hegemony. Since no state is likely to achieve global hegemony, however, the world is condemned to perpetual great-power competition.

    This unrelenting pursuit of power means that great powers are inclined to look for opportunities to alter the distribution of world power in their favor. They will seize these opportunities if they have the necessary capability. Simply put, great powers are primed for offense. But not only does a great power seek to gain power at the expense of other states, it also tries to thwart rivals bent on gaining power at its expense. Thus, a great power will defend the balance of power when looming change favors another state, and it will try to undermine the balance when the direction of change is in its own favor.

    Why do great powers behave this way? My answer is that the structure of the international system forces states which seek only to be secure nonetheless to act aggressively toward each other. Three features of the international system combine to cause states to fear one another: 1) the absence of a central authority that sits above states and can protect them from each other, 2) the fact that states always have some offensive military capability, and 3) the fact that states can never be certain about other states' intentions. Given this fear—which can never be wholly eliminated—states recognize that the more powerful they are relative to their rivals, the better their chances of survival. Indeed, the best guarantee of survival is to be a hegemon, because no other state can seriously threaten such a mighty power.

    This situation, which no one consciously designed or intended, is genuinely tragic. Great powers that have no reason to fight each other—that are merely concerned with their own survival—nevertheless have little choice but to pursue power and to seek to dominate the other states in the system. This dilemma is captured in brutally frank comments that Prussian statesman Otto von Bismarck made during the early 1860s, when it appeared that Poland, which was not an independent state at the time, might regain its sovereignty. "Restoring the Kingdom of Poland in any shape or form is tantamount to creating an ally for any enemy that chooses to attack us," he believed, and therefore he advocated that Prussia should "smash those Poles till, losing all hope, they lie down and die; I have every sympathy for their situation, but if we wish to survive we have no choice but to wipe them out."

    Although it is depressing to realize that great powers might think and act this way, it behooves us to see the world as it is, not as we would like it to be. For example, one of the key foreign policy issues facing the United States is the question of how China will behave if its rapid economic growth continues and effectively turns China into a giant Hong Kong. Many Americans believe that if China is democratic and enmeshed in the global capitalist system, it will not act aggressively; instead it will be content with the status quo in Northeast Asia. According to this logic, the United States should engage China in order to promote the latter's integration into the world economy, a policy that also seeks to encourage China's transition to democracy. If engagement succeeds, the United States can work with a wealthy and democratic China to promote peace around the globe.

    Unfortunately, a policy of engagement is doomed to fail. If China becomes an economic powerhouse it will almost certainly translate its economic might into military might and make a run at dominating Northeast Asia. Whether China is democratic and deeply enmeshed in the global economy or autocratic and autarkic will have little effect on its behavior, because democracies care about security as much as nondemocracies do, and hegemony is the best way for any state to guarantee its own survival. Of course, neither its neighbors nor the United States would stand idly by while China gained increasing increments of power. Instead, they would seek to contain China, probably by trying to form a balancing coalition. The result would be an intense security competition between China and its rivals, with the ever-present danger of great-power war hanging over them. In short, China and the United States are destined to be adversaries as China's power grows.

OFFENSIVE REALISM

This book offers a realist theory of international politics that challenges the prevailing optimism about relations among the great powers. That enterprise involves three particular tasks.

    I begin by laying out the key components of the theory, which I call "offensive realism." I make a number of arguments about how great powers behave toward each other, emphasizing that they look for opportunities to gain power at each others' expense. Moreover, I identify the conditions that make conflict more or less likely. For example, I argue that multipolar systems are more war-prone than are bipolar systems, and that multipolar systems that contain especially powerful states—potential hegemons—are the most dangerous systems of all. But I do not just assert these various claims; I also attempt to provide compelling explanations for the behaviors and the outcomes that lie at the heart of the theory. In other words, I lay out the causal logic, or reasoning, which underpins each of my claims.

    The theory focuses on the great powers because these states have the largest impact on what happens in international politics. The fortunes of all states—great powers and smaller powers alike—are determined primarily by the decisions and actions of those with the greatest capability. For example, politics in almost every region of the world were deeply influenced by the competition between the Soviet Union and the United States between 1945 and 1990. The two world wars that preceded the Cold War had a similar effect on regional politics around the world. Each of these conflicts was a great-power rivalry, and each cast a long shadow over every part of the globe.

    Great powers are determined largely on the basis of their relative military capability. To qualify as a great power, a state must have sufficient military assets to put up a serious fight in an all-out conventional war against the most powerful state in the world. The candidate need not have the capability to defeat the leading state, but it must have some reasonable prospect of turning the conflict into a war of attrition that leaves the dominant state seriously weakened, even if that dominant state ultimately wins the war. In the nuclear age great powers must have a nuclear deterrent that can survive a nuclear strike against it, as well as formidable conventional forces. In the unlikely event that one state gained nuclear superiority over all of its rivals, it would be so powerful that it would be the only great power in the system. The balance of conventional forces would be largely irrelevant if a nuclear hegemon were to emerge.

    My second task in this book is to show that the theory tells us a lot about the history of international politics. The ultimate test of any theory is how well it explains events in the real world, so I go to considerable lengths to test my arguments against the historical record. Specifically, the focus is on great-power relations from the start of the French Revolutionary and Napoleonic Wars in 1792 until the end of the twentieth century. Much attention is paid to the European great powers because they dominated world politics for most of the past two hundred years. Indeed, until Japan and the United States achieved great-power status in 1895 and 1898, respectively, Europe was home to all of the world's great powers. Nevertheless, the book also includes substantial discussion of the politics of Northeast Asia, especially regarding imperial Japan between 1895 and 1945 and China in the 1990s. The United States also figures prominently in my efforts to test offensive realism against past events.

    Some of the important historical puzzles that I attempt to shed light on include the following:

1) What accounts for the three longest and bloodiest wars in modern history—the French Revolutionary and Napoleonic Wars (1792-1815), World War I (1914-18), and World War II (1939-45)—conflicts that involved all of the major powers in the system?

2) What accounts for the long periods of relative peace in Europe between 1816 and 1852, 1871 and 1913, and especially 1945 and 1990, during the Cold War?

3) Why did the United Kingdom, which was by far the wealthiest state in the world during the mid-nineteenth century, not build a powerful military and try to dominate Europe? In other words, why did it behave differently from Napoleonic France, Wilhelmine Germany, Nazi Germany, and the Soviet Union, all of which translated their economic might into military might and strove for European hegemony?

4) Why was Bismarckian Germany (1862-90) especially aggressive between 1862 and 1870, fighting two wars with other great powers and one war with a minor power, but hardly aggressive at all from 1871 until 1890, when it fought no wars and generally sought to maintain the European status quo?

5) Why did the United Kingdom, France, and Russia form a balancing coalition against Wilhelmine Germany before World War I, but fail to organize an effective alliance to contain Nazi Germany?

6) Why did Japan and the states of Western Europe join forces with the United States against the Soviet Union in the early years of the Cold War, even though the United States emerged from World War II with the most powerful economy in the world and a nuclear monopoly?

7) What explains the commitment of American troops to Europe and Northeast Asia during the twentieth century? For example, why did the United States wait until April 1917 to join World War I, rather than enter the war when it broke out in August 1914? For that matter, why did the United States not send troops to Europe before 1914 to prevent the outbreak of war? Similarly, why did the United States not balance against Nazi Germany in the 1930s or send troops to Europe before September 1939 to prevent the outbreak of World War II?

8) Why did the United States and the Soviet Union continue building up their nuclear arsenals after each had acquired a secure second-strike capability against the other? A world in which both sides have an "assured destruction" capability is generally considered to be stable and its nuclear balance difficult to overturn, yet both superpowers spent billions of dollars and rubles trying to gain a first-strike advantage.

    Third, I use the theory to make predictions about great-power politics in the twenty-first century. This effort may strike some readers as foolhardy, because the study of international relations, like the other social sciences, rests on a shakier theoretical foundation than that of the natural sciences. Moreover, political phenomena are highly complex; hence, precise political predictions are impossible without theoretical tools that are superior to those we now possess. As a result, all political forecasting is bound to include some error. Those who venture to predict, as I do here, should therefore proceed with humility, take care not to exhibit unwarranted confidence, and admit that hindsight is likely to reveal surprises and mistakes.

    Despite these hazards, social scientists should nevertheless use their theories to make predictions about the future. Making predictions helps inform policy discourse, because it helps make sense of events unfolding in the world around us. And by clarifying points of disagreement, making explicit forecasts helps those with contradictory views to frame their own ideas more clearly. Furthermore, trying to anticipate new events is a good way to test social science theories, because theorists do not have the benefit of hindsight and therefore cannot adjust their claims to fit the evidence (because it is not yet available). In short, the world can be used as a laboratory to decide which theories best explain international politics. In that spirit, I employ offensive realism to peer into the future, mindful of both the benefits and the hazards of trying to predict events.

The Virtues and Limits of Theory

It should be apparent that this book is self-consciously theoretical. But outside the walls of academia, especially in the policy world, theory has a bad name. Social science theories are often portrayed as the idle speculations of head-in-the-clouds academics that have little relevance to what goes on in the "real world." For example, Paul Nitze, a prominent American foreign-policy maker during the Cold War, wrote, "Most of what has been written and taught under the heading of `political science' by Americans since World War II has been ... of limited value, if not counterproductive, as a guide to the actual conduct of policy." In this view, theory should fall almost exclusively within the purview of academics, whereas policymakers should rely on common sense, intuition, and practical experience to carry out their duties.

    This view is wrongheaded. In fact, none of us could understand the world we live in or make intelligent decisions without theories. Indeed, all students and practitioners of international politics rely on theories to comprehend their surroundings. Some are aware of it and some are not, some admit it and some do not; but there is no escaping the fact that we could not make sense of the complex world around us without simplifying theories. The Clinton administration's foreign policy rhetoric, for example, was heavily informed by the three main liberal theories of international relations: 1) the claim that prosperous and economically interdependent states are unlikely to fight each other, 2) the claim that democracies do not fight each other, and 3) the claim that international institutions enable states to avoid war and concentrate instead on building cooperative relationships.

    Consider how Clinton and company justified expanding the membership of the North Atlantic Treaty Organization (NATO) in the mid-1990s. President Clinton maintained that one of the chief goals of expansion was "locking in democracy's gains in Central Europe," because "democracies resolve their differences peacefully." He also argued that the United States should foster an "open trading system," because "our security is tied to the stake other nations have in the prosperity of staying free and open and working with others, not working against them." Strobe Talbott, Clinton's Oxford classmate and deputy secretary of state, made the same claims for NATO enlargement: "With the end of the cold war, it has become possible to construct a Europe that is increasingly united by a shared commitment to open societies and open markets." Moving the borders of NATO eastward, he maintained, would help "to solidify the national consensus for democratic and market reforms" that already existed in states like Hungary and Poland and thus enhance the prospects for peace in the region.

    In the same spirit, Secretary of State Madeleine Albright praised NATO's founders by saying that "[t]heir basic achievement was to begin the construction of the ... network of rule-based institutions and arrangements that keep the peace." "But that achievement is not complete," she warned, and "our challenge today is to finish the post-war construction project ... [and] expand the area of the world in which American interests and values will thrive."

    These examples demonstrate that general theories about how the world works play an important role in how policymakers identify the ends they seek and the means they choose to achieve them. Yet that is not to say we should embrace any theory that is widely held, no matter how popular it may be, because there are bad as well as good theories. For example, some theories deal with trivial issues, while others are opaque and almost impossible to comprehend. Furthermore, some theories have contradictions in their underlying logic, while others have little explanatory power because the world simply does not work the way they predict. The trick is to distinguish between sound theories and defective ones. My aim is to persuade readers that offensive realism is a rich theory which sheds considerable light on the workings of the international system.

    As with all theories, however, there are limits to offensive realism's explanatory power. A few cases contradict the main claims of the theory, cases that offensive realism should be able to explain but cannot. All theories face this problem, although the better the theory, the fewer the anomalies.

    An example of a case that contradicts offensive realism involves Germany in 1905. At the time Germany was the most powerful state in Europe. Its main rivals on the continent were France and Russia, which some fifteen years earlier had formed an alliance to contain the Germans. The United Kingdom had a tiny army at the time because it was counting on France and Russia to keep Germany at bay. When Japan unexpectedly inflicted a devastating defeat on Russia between 1904 and 1905, which temporarily knocked Russia out of the European balance of power, France was left standing virtually alone against mighty Germany. Here was an excellent opportunity for Germany to crush France and take a giant step toward achieving hegemony in Europe. It surely made more sense for Germany to go to war in 1905 than in 1914. But Germany did not even seriously consider going to war in 1905, which contradicts what offensive realism would predict.

    Theories encounter anomalies because they simplify reality by emphasizing certain factors while ignoring others. Offensive realism assumes that the international system strongly shapes the behavior of states. Structural factors such as anarchy and the distribution of power, I argue, are what matter most for explaining international politics. The theory pays little attention to individuals or domestic political considerations such as ideology. It tends to treat states like black boxes or billiard balls. For example, it does not matter for the theory whether Germany in 1905 was led by Bismarck, Kaiser Wilhelm, or Adolf Hitler, or whether Germany was democratic or autocratic. What matters for the theory is how much relative power Germany possessed at the time. These omitted factors, however, occasionally dominate a state's decision-making process; under these circumstances, offensive realism is not going to perform as well. In short, there is a price to pay for simplifying reality.

    Furthermore, offensive realism does not answer every question that arises in world politics, because there will be cases in which the theory is consistent with several possible outcomes. When this occurs, other theories have to be brought in to provide more precise explanations. Social scientists say that a theory is "indeterminate" in such cases, a situation that is not unusual with broad-gauged theories like offensive realism.

(Continues...)

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Excerpted from The Tragedy of Great Power Politics by John J. Mearsheimer. Copyright © 2001 by John J. Mearsheimer. Excerpted by permission. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.

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