The United States recently wound down a protracted war in Iraq and is currently fighting another one in Afghanistan. At the same time, a robust debate continues about what kind of policy Washington should adopt with respect to a turbulent Middle East and a rising China. While analysts differ on the best approach going forward, a widespread sense persists that the domestic climate is hardly conducive to large-scale military action. Political scientist John Mueller has spoken of an “Iraq syndrome,” comparable to the one following the Vietnam War, that is likely to constrain American interventionism for years to come.Footnote 1 Robert Gates, the former Secretary of Defense, agrees, telling an audience of West Point cadets that “in my opinion, any future defense secretary who advises the president to again send a big American land army into Asia or the Middle East or Africa should ‘have his head examined,’ as General MacArthur so delicately put it.”Footnote 2 This situation raises an important question: what kind of policy can the United States pursue that ensures its security while minimizing the likelihood of war?
Practitioners likely will be skeptical of our attempt to contribute to this debate. David Newsom, a former diplomat, notes “the attitude of many in government that academia represents an irrelevant ivory tower.”Footnote 3 Paul Nitze was more direct, arguing that “most of what has been written and taught under the heading of ‘political science’ … has also been of limited value, if not counterproductive as a guide to the conduct of actual policy.”Footnote 4 Stephen Walt, meanwhile, discerns “a low regard for theory” on the part of important officials and finds little “evidence that policy makers pay systematic attention to academic writings on international affairs.”Footnote 5
One reason for this attitude is that political scientists tend to shy away from policy relevant work. According to Joseph Nye, “scholars are paying less attention to questions about how their work relates to the policy world.”Footnote 6 Why academics have withdrawn to the ivory tower is an open question, but the profession's attitude toward policy work—ranging from indifference to hostility—is at least partially to blame. “In many departments,” notes Nye, “a focus on policy can hurt one's career.”Footnote 7 Walt reaches the same conclusion: “Policy relevance is simply not a criterion that the academy values. Indeed, there is a clear bias against it.”Footnote 8 Similarly, Bruce Jentleson and Ely Ratner declare that “academia's dominant organizational culture … devalues policy relevance.”Footnote 9
Our own position is that political scientists can and should contribute to policy debates. The reason that political scientists can make a valuable contribution is simple, but cannot be repeated enough: theory and policy are inextricably linked. Although they may not be self-conscious in their use of theory, policy makers figure out what events or factors to focus on and what policies to pursue based on the theories they find most convincing. As Walt points out, theory is indispensable to policy—to the extent that it helps decision makers to diagnose their problems, to anticipate events, to formulate prescriptions for action, and to evaluate the results of their policies.Footnote 10 Thus, we have a responsibility as scholars to foster a robust debate about our preferred theories and their competitors. After all, wise policy choices depend on a vigorous marketplace of ideas.Footnote 11
Political scientists should contribute to these debates as scholars, which is to say that they must be attentive to logic and evidence. As Patrick Thaddeus Jackson and Stuart Kaufman explain, if we want to remain “on the scientific side of the thin line separating science from politics,” the key issue is “whether, given our assumptions, our conclusions follow rigorously from the evidence and logic we provide.”Footnote 12 In the case at hand, this involves two tasks. First, we must take a handful of plausible assumptions and logically deduce a set of foreign policy prescriptions. Second, we must show—through a detailed examination of the historical record—that had states adhered to these prescriptions, they would likely have enhanced their security without going to war and, conversely, that their embrace of alternative theories of action led them down the path to war.
With these requirements in mind, we describe and defend a prescriptive realist theory of foreign policy to guide American decision makers as they navigate the current environment. Briefly, the theory says that if they want to ensure their security, great powers such as the United States should balance against other great powers and also against hostile minor powers that inhabit strategically important regions of the world. We then show that had the great powers followed our theory's prescriptions, some of the most important wars of the past century might have been averted. Specifically, the world wars might not have occurred, and the United States might not have gone to war in either Vietnam or Iraq. In other words, realism as we conceive it offers the prospect of security without war.
Our argument is likely to be controversial because few observers think that a realist foreign policy can minimize the chances of war. Indeed, the main reason that “no one loves a political realist” arises from the intimate association that realism is thought to have with war.Footnote 13 The criticism takes several forms: some argue that realism is a license for aggression; others that it perpetuates competitive behavior; still others that it advances few ideas on how to overcome interstate conflict, thus foreclosing possibilities for progressive change.Footnote 14 As a result, most analysts consider realism an inappropriate guide to current US foreign policy.
Liberals have been quite outspoken in leveling these kinds of charges, claiming that realism neglects transformative developments such as globalization, democratization, and the proliferation of international institutions, all of which offer the possibility of an enduring peace.Footnote 15 Robert Keohane observes that realism “is better at telling us why we are in such trouble than how to get out of it.”Footnote 16 Realism, that is, may explain why international politics is conflictual, but provides little guidance for overcoming that conflict peacefully. For Keohane, such complacency is morally unacceptable, leading him to conclude that “no serious thinker could … be satisfied with Realism as the correct theory of world politics.” He advises scholars to focus on international institutions instead: “Unlike Realism, theories that attempt to explain rules, norms, and institutions help us to understand how to create patterns of cooperation that could be essential to our survival.”Footnote 17 Bruce Russett adopts a similar tack in his defense of democratic peace theory. Realism, he notes, “has no place for an expectation that democracies will not fight each other.”Footnote 18 This is important because understanding the sources of the democratic peace can have the effect of a self-fulfilling prophecy. By adopting a skeptical attitude toward the democratic peace, then, realists are at least indirectly diminishing the prospects for a world without war.Footnote 19
The constructivist charge is that realist discourse perpetuates the very competition for power that realists purport to explain. Anarchy, after all, is what states make of it; so if realists describe international politics as competitive, then states are more likely to act in precisely that way.Footnote 20 This is, in fact, Alexander Wendt's critique in his seminal statement of constructivism. The problem with realism, he argues, is that it refuses to acknowledge that international politics can be anything but Hobbesian and in doing so impedes progress. In Wendt's own words, “Realism's commitment to self-interest participates in creating and reifying self-help worlds in international politics. To that extent Realism is taking an at least implicit stand not only on what international life is, but on what it should be; it becomes a normative as well as a positive theory.”Footnote 21
Critics have zeroed in on modern realism, the branch of the tradition that informs our theory.Footnote 22 Classical realism has recently undergone a revival among realism's critics. Classical realists are described as being less fixated on narrow power considerations than their successors and more attuned to transformative developments in world politics. They therefore have more to contribute to the cause of peace. Richard Ned Lebow has been a forceful advocate of this position, lamenting that the structural turn in realism has led to a vicious circle: “The language of classical realism, with all its subtlety, commitment to caution and respect for conventions, has been replaced by the cruder language of modern realism and its emphasis on power and expediency. These maxims, which have become conventional wisdom, guide policymakers, and their behavior in turn appears to confirm the assumptions of the modern realist discourse.” Lebow concedes that many realists opposed the Iraq War and cannot be held responsible for the failures of US foreign policy, but in the same breath warns that modern realist discourse “has the potential to turn American hegemony into another tragedy.”Footnote 23
Michael Williams has joined the debate in a similar fashion, reconstructing a “wilful” realist tradition from the writings of Hobbes, Rousseau, and Morgenthau. For him, “wilful Realism is deeply concerned that a recognition of the centrality of power in politics does not result in the reduction of politics to pure power, and particularly to the capacity to wield violence. It seeks, on the contrary, a politics of limits that recognizes the destructive and productive dimensions of politics, and that maximizes its positive possibilities while minimizing its destructive potential.”Footnote 24 Williams is explicit that his “wilful” variant stands in stark contrast to most understandings of realism today, implying that modern realists do reduce politics to power maximization and eschew any limits on the exercise of that power, with destructive consequences.
We dispute the conventional characterization of realism. Our position is that it is possible to develop a prescriptive realist theory—one derived from the core assumptions of modern realism—that meets a state's security needs while minimizing the likelihood of war.Footnote 25
Our case proceeds as follows. We begin by describing our prescriptive realist theory of foreign policy. Next we describe an alternative liberal approach that promises perpetual peace rather than the mere stability implied by our theory. We then suggest that had the great powers behaved as our theory advises, some of the most important wars of the past century might have been avoided. At the same time, we show that liberalism was at least partially to blame for the outbreak of these wars. We conclude by using our theory to outline a foreign policy for the United States, one that we argue should make the US secure, while simultaneously minimizing the likelihood that it will become embroiled in future wars.
A Prescriptive Realist Theory
Here we develop a prescriptive realist theory that tells great powers such as the United States how they should behave if they want to ensure their security.Footnote 26 The prescriptions can be briefly summarized. If they are dealing with peer competitors, great powers should balance—they should build up their capabilities and make it clear to actual and potential great power rivals that they will oppose their attempts at expansion. At the same time, they should take a relaxed view toward developments involving minor powers and, at most, should balance against hostile minor powers that inhabit strategically important areas of the world.
We begin with three core assumptions. First, the international system is anarchic—there is no government above states to enforce agreements among them or to protect them from one another.Footnote 27 Second, states cannot know the present and, especially, the future intentions of others.Footnote 28 Third, interstate war is an unpredictable enterprise with potentially devastating consequences. As Robert Jervis observes, “statesmen know that to enter a war is to set off a chain of unpredictable and uncontrollable events.”Footnote 29 Of course, the more powerful a state, the more likely it is to prevail in battle. But superior strength does not guarantee victory; weaker states can and sometimes do defeat stronger opponents.Footnote 30
The fundamental prescription that follows from these premises is that states should be attentive to the balance of power. Because there is no government to protect them and they cannot know the intentions of others, great powers must ultimately provide for their own security. This, in turn, means that they must worry about how much power they have relative to their competitors, where power refers to military and economic assets.Footnote 31
Before we turn to the task of laying out more specific prescriptions, a few words are in order about the status of our theory. For one thing, its assumptions and its emphasis on power competition clearly place it within the modern realist tradition.Footnote 32 At the same time, however, the task we have set ourselves is quite different from the one that preoccupies most realist scholars. They are engaged in a primarily explanatory enterprise. According to John Mearsheimer, “realism is mainly a descriptive theory. It explains how great powers have behaved in the past and how they are likely to behave in the future.”Footnote 33 This is not to say that realists are uninterested in prescription. Indeed, the opposite is closer to the truth. As Marc Trachtenberg points out, “At the heart of the realist tradition is an interpretation of why things go wrong, and thus involves claims about how international politics should work and what sort of policies should be pursued.”Footnote 34 But explanation is the primary goal and prescriptions follow. We take a different tack and set out with the express purpose of creating a prescriptive theory.Footnote 35
Dealing with Great Powers
Given the dangers of weakness, great powers should balance against more powerful peer competitors. What does this entail? Most important, it means that they should build up their military and economic resources. The reason is that by doing so they will array more capabilities against a competitor, thereby increasing the probability that they will deter it from attacking them or that they will defeat it in the event that deterrence fails. As Charles Glaser explains, “All else being equal, a state is more secure when it possesses the military capabilities required to protect its territory from attack. These capabilities could include those required to deter attack … They could also include those required to directly protect the state.”Footnote 36 Balancing also has a crucial signaling component to it. The balancer must not only build up its capabilities, but must also make it clear to the more powerful state that it will vigorously oppose any attempt at expansion. “In effect,” explains Mearsheimer, “the balancer draws a line in the sand and warns the aggressor not to cross it.”Footnote 37
Aspiring balancers can also achieve their aims by allying with other states against an especially powerful peer competitor. Kenneth Waltz offers a neat summary of the logic, noting that states form alliances in the hope of “achiev[ing] enough defensive or deterrent strength to dissuade adversaries from attacking.”Footnote 38 Mearsheimer makes essentially the same point: “recruiting allies increases the amount of firepower confronting an aggressor, which in turn increases the likelihood that deterrence will work.”Footnote 39 As in the case of building up one's own capabilities, alliances are more likely to have their desired deterrent effect if the allies make it clear to their common adversary that they are resolved to oppose it in the event that it attempts to expand.Footnote 40
Our recommendation that great powers should balance does not imply that they should build up their capabilities without limit. Taken to its logical extreme, this would be a prescription for bankruptcy. Therefore, states should increase their power until they have the resources to confront their opponent with the prospect of having to fight a protracted war of attrition, a prospect that should be sufficient to deter most aggressors.Footnote 41 Allies should help in this cause, as even highly expansionist states will be reluctant to court war on multiple fronts. Finally, in the nuclear age, a secure second-strike capability is essential to deter nuclear-armed adversaries.Footnote 42
There are several potential objections to our balancing prescription. The first is that some opponents may be difficult or impossible to deter. If committed enough to expansion, an adversary may go on the offensive even if others build up formidable capabilities against it and clearly signal their willingness to use them. Nevertheless, states that want to ensure their security are better off balancing in these situations than not doing so. Deterrence may not be easy, but it is also the case that the more power states array against an adversary, the more likely it is to be deterred. Also, if deterrence fails and war breaks out, states that have been balancing up to that point will be in a better position to defeat an aggressor than states that have not been building up their power.Footnote 43
Another potential objection comes from the defensive variant of realism. The basic argument is that balancing aggressively against a powerful adversary may make it feel less secure, thereby increasing the likelihood that it attacks. Put slightly differently, balancing can generate a spiral of fear that ultimately leads an adversary to lash out at those balancing against it.Footnote 44 This analysis yields an obvious alternative prescription: rather than balancing and triggering a spiral of fear, a state should try to reassure its adversary by not balancing especially aggressively. The effect of this strategy, in many cases, is that the state trying to do the reassuring has now increased its vulnerability. This is a reasonable course of action as long as the balancer is quite confident that its potential adversary has benign intentions. And, indeed, defensive realists argue that, under a range of conditions, states can achieve such confidence.Footnote 45 Our position, however, is that intentions are unknowable, and even if known, are subject to change.Footnote 46 This being the case, no state should knowingly put itself in a position of weakness.
Yet another potential objection to our prescription comes from offensive realism, which would advocate buck-passing—trying to get another state to bear the burden of containing a common powerful adversary—rather than balancing.Footnote 47 Upon close inspection, however, buck-passing is rarely a good formula for procuring security. Its chief drawback is that it undermines deterrence, which makes it more likely that the threat will attack and that war will break out. This can reduce a buck-passer's security in several ways. For one thing, the threat may defeat the buck-catcher, become more powerful, and now pose an even greater threat to the buck-passer.Footnote 48 Alternatively, the buck-catcher may defeat the threat, thereby amassing formidable capabilities and posing a serious danger to the buck-passer's security. Then there is the ever-present possibility that the buck-passer will have to join the war at some point in order to bring it to a favorable conclusion. Once it does so, it runs the risk of paying substantial costs up to and including defeat. In other words, unless the war ends in a stalemate—and because war is an unpredictable enterprise, it is impossible to be sure that it will—the buck-passer has reduced its security. Thus, great powers considering buck-passing would be well advised to balance instead, thereby enhancing deterrence and avoiding the risks entailed in war altogether.
Some would argue that buck-passing is the rational strategy for a great power confronting an especially powerful peer competitor. By getting another state to deal with the threat, the buck-passer will be secure without having to pay the costs of balancing.Footnote 49 This is indeed a rational strategy if the buck-passer is quite confident that the war will end in a stalemate. The problem, however, is that the outcome of a war, especially a great power war, is by no means certain. A stalemate is one possible outcome, but so too are victory for the threat, victory for the buck-catcher, and intervention by the buck-passer and, as we have shown, all of these alternative outcomes threaten to reduce a buck-passer's security rather than increase it. The rational security-enhancing strategy, then, is to balance and try to check the threat oneself or in concert with others.
Proponents of bandwagoning could also object to our balancing prescription. States bandwagon when they align with a particularly powerful state instead of against it. There are two ways in which such a policy might enhance a state's security. First, by siding with the stronger state the bandwagoner may divert it elsewhere and thereby avoid an attack. Second, a bandwagoner may be allowed to share some of the spoils of victory—usually a disproportionately small share—with the stronger state, and thereby enhance its power and security.Footnote 50 The problem is that in either case—the weaker state gets out of the way or lends its active support—the bandwagoner makes it more likely that the stronger state will expand and increase its relative power. Therefore, bandwagoning makes little sense for a great power that wants to remain secure.
Its emphasis on balancing notwithstanding, our theory does occasionally prescribe war. After all, if balancing fails and an aggressor attacks, then a great power will have little choice but to defend itself and its allies. Preemption—or anticipatory self-defense—is also consistent with our theory, assuming that an adversary is preparing to attack and there are military advantages to striking first. Preventive war, however, is another matter. As Richard Betts points out, “preventive war is almost always a bad choice, strategically as well as morally.”Footnote 51 The reason is that the probability that a rising power will eventually attack is less than one hundred percent, while the costs and risks of starting a war with it are certain. As Betts concludes, it may not be “comforting to rely on deterrence to contain aggression, but it is better than precipitating precisely the clash that is feared.”Footnote 52
In sum, our theory tells great powers to balance against more powerful peers if they want to be secure. Our advice, then, is in keeping with the recommendation of Roman military writer Publius Flavius Vegetius Renatus: “If you wish for peace, prepare for war.”Footnote 53
Dealing with Minor Powers
What does our theory prescribe when a great power is confronted by a minor power rather than another great power? The answer depends on whether or not the minor power is located in an area that is strategically important to the great power. An area is strategically important if its control by a hostile state would give that state the material capability to threaten the security of the great power. In the modern period, strategically important areas are those that contain significant industrial resources or reserves of oil.Footnote 54
A great power confronted by a minor power in a strategically unimportant area should take a relaxed view toward it.Footnote 55 One reason is that the minor power is not strong enough to pose a direct threat to the great power's security. Moreover, even if the minor power manages to establish control over its immediate neighborhood, it will still not have the wherewithal to threaten the security of the great power. In those cases where a great power faces a minor power that is located in a strategically important area of the world, it should balance, which is to say deter the minor power from seeking to expand its control. Balancing or containment should be fairly straightforward in such cases since the great power already has the material advantage required to deter its weaker opponent.Footnote 56 All it has to do is make its interests clear and draw a line in the sand. At the same time, the great power should encourage other weak states in that area of the world to balance against the hostile minor power. Again, this should not be too difficult. Because the hostile power threatens their security directly, those states have a powerful incentive to contain it.Footnote 57
Great powers should also take a relaxed view toward minor powers that may join forces with one of their great power adversaries. The reason is that these states are weak and therefore do not add much to the capabilities of a rival great power.
Why should a great power not simply go to war with a minor power that threatens its interests? After all, the great power has a massive capability advantage that it could use to defeat the minor power and impose its preferred solution. One reason not to go to war is that balancing generally works against minor powers. Because they are so weak they are eminently containable. Thus, the great power can get what it wants on the cheap without incurring the risks and costs associated with war. Moreover, wars, even brushfire wars, involve political, military, and economic costs. Indeed, there is always the chance that the great power could miscalculate and find itself embroiled in a protracted and bloody stalemate. Ivan Arreguin-Toft, for example, has shown that under some conditions great powers can even lose wars against weak opponents.Footnote 58 A great power would therefore do well to think twice before using force against a minor power, especially given the limited stakes usually involved.
In sum, great powers should take a relaxed attitude toward minor powers. In the vast majority of cases, they can ignore weak states without negative repercussions for their security, and in those few cases where minor powers are located in strategically important regions, balancing should be sufficient.
The Liberal Alternative
In the preceding section, we developed a prescriptive realist theory that we argue minimizes the likelihood of interstate war. In the great power realm, it puts a premium on deterrence, which should, theoretically, reduce the incidence of war by making potential aggressors think twice before attacking. As for their dealings with minor powers, the theory tells great powers that war is rarely necessary; indifference or containment are better options. Overall, then, we expect war to be infrequent if the great powers follow our prescriptions.
Even if there is good evidence for our claims, many readers will not be satisfied with our prescriptive realism. The reason is that we have, at best, provided a recipe for stability, not real peace. This sentiment is well-expressed by Keohane, who has accused realism of moral complacency and has argued that scholars should try to figure out how to promote cooperation for the benefit of mankind. What students of international politics need to do, he continues, is combine “multidimensional scholarly analysis with more visionary ways of seeing the future.”Footnote 59
Liberal international relations scholars claim to have uncovered the causes of peace. The first of these is democracy. The basic argument is that democracies can be relied upon to remain at peace with one another because they share common norms of live-and-let-live and domestic institutions that constrain the recourse to war.Footnote 60 The second liberal cause of peace is institutions, that is rules that prescribe and proscribe acceptable and unacceptable forms of behavior.Footnote 61 Simply put, institutions enhance the prospects for cooperation because they “provide information, reduce transaction costs, make commitments more credible, establish focal points for coordination, and … facilitate the operation of reciprocity.” They are therefore essential “components of any lasting peace.”Footnote 62 The final liberal cause of peace is economic interdependence. John Oneal and Bruce Russett describe the logic well: “Commercial relations draw states into a web of mutual self interest that constrains them from using force against one another.”Footnote 63 Of course, liberalism is not monolithic. Some liberal scholars emphasize only one cause of peace, others assign different weights to the three elements, and still others argue that a “Kantian tripod” made up of “representative democracy … economic interdependence … [and] international law (and in the contemporary era, international organizations) … is essential to maintaining the structure of stable peace.”Footnote 64
Clear prescriptions follow for democracies that want to ensure their security. One set of prescriptions revolves around regime type: beware of authoritarian states, support the spread of democracy worldwide—it is on this point that liberals and neoconservatives join forces—and defend democracy where it is threatened by other ideologies or political arrangements.Footnote 65 Another set of prescriptions focuses on institutions: democracies should support their proliferation and turn to them when conflicts loom on the horizon. Finally, democracies should foster economic interdependence whenever they have an opportunity to do so. In short, they should pursue something akin to a “liberal internationalist” foreign policy, one that involves promoting “open markets, international institutions, cooperative security, democratic community, progressive change, collective problem solving, [and] the rule of law.”Footnote 66
This, then, is the alternative liberal vision of foreign policy, one that emphasizes democracy, institutions, and interdependence rather than the balance of power, and that holds out the prospect of peace rather than stability. The question now is an empirical one: does the historical record support our claim that states can avoid war if they are attentive to the balance of power, or the liberal proposition that democracy, institutions, and interdependence are the cause of peace?
The Historical Record
A brief survey of the historical record suggests that had states acted according to the dictates of our realist theory, then some of the most consequential wars of the past century might have been avoided.Footnote 67 Specifically, both of the world wars were made more likely by the failure of Germany's potential victims to balance aggressively enough against it. As Mearsheimer observes, “German power could have been countered before both world wars had the other European powers balanced efficiently against Germany. If so, Germany might have been deterred, and war prevented on both occasions. However, the other powers twice failed to do so.”Footnote 68 The American decision to fight in Vietnam also violates our theory's prescriptions: because the balance of power was not at stake, the United States should not have become militarily involved there. A similar story applies to the Iraq war. Had the Bush administration followed our prescriptions, it would have tried to contain Saddam Hussein rather than attacking him in 2003.
Even as it lends support to our argument, the evidence also suggests that liberalism was partially to blame for these wars. Deterrence failed in the world war cases at least in part because Britain and France acted on the basis of a liberal worldview that minimized the importance of balancing as a strategy for keeping the peace.Footnote 69 Liberalism played a more active role in the other two cases. The decision to fight in Vietnam owed a great deal to the United States' ideological aversion to communism. The Bush administration, meanwhile, went to war in Iraq with the express purpose of spreading democracy in the Middle East. We examine each of the four wars in turn.
World War I
Our theory prescribes balancing against especially powerful peer competitors. In the early twentieth century, this would have meant balancing against Germany, which had the strongest army in Europe and was also the continent's leading industrial power. In fact, by conventional measures, Imperial Germany was more than twice as powerful as France and Russia and one and a half times stronger than Britain.Footnote 70
France and Russia—the great powers most immediately threatened by Germany—balanced vigorously in the decade before World War I.Footnote 71 The British, however, did not, even though they knew Germany was a potential hegemon.Footnote 72 This is not to say that Britain gave Germany the green light to bid for continental domination. Foreign Secretary Sir Edward Grey never committed to remaining neutral in the event of war. At the same time, however, he also refused to give France and Russia an unconditional commitment to come to their defense.Footnote 73 As John and Peter Coogan explain, Britain maintained a position of “determined political ambiguity” until the end.Footnote 74 Nor did the British build sufficient military capabilities to balance against Germany effectively. Keith Wilson concludes that “as instruments with which to deter a bid on the part of another Power for the hegemony of Europe, both the British Army and the British Navy left much to be desired.”Footnote 75 Finally, Britain improved its relations with Germany in the years immediately before the war, cooperating on peripheral issues such as the Balkans, Portuguese colonies in Africa, and the Baghdad Railway, and even seeming to reach a tacit understanding about the naval arms race.Footnote 76 In short, Britain failed to build up its capabilities and draw a line in the sand.
A good case can be made that Britain's failure to balance aggressively made World War I more likely. If Imperial Germany had been convinced that it would have to fight all three members of the Triple Entente from the outset, it may well have been deterred from going to war. After all, it would have been at a 2:1 power disadvantage to a British-French-Russian coalition. As it was, however, the Germans were led to believe that there was a chance that they would only have to take on a Franco-Russian combination, which is to say an alliance that was weaker than Germany. The bottom line, according to Sean Lynn-Jones, is that “it is highly likely that a clearer statement of Britain's intention to intervene on behalf of France would have deterred Germany, thereby preventing or at least limiting World War I.”Footnote 77
Critics could respond that Britain's inadequate balancing was of little consequence because Germany was undeterrable and would have gone to war regardless. As the debate about the Great War has evolved, it has become increasingly clear that Germany knowingly risked war, largely for preventive reasons.Footnote 78 One scholar, in fact, has gone so far as to argue that even the expectation of a long and protracted war against the Triple Entente was not enough to dissuade the Germans from making a grab for regional hegemony.Footnote 79 Few would endorse this position, however: the preponderance of evidence suggests that German leaders wanted not a world war involving Britain, but a continental war against France and Russia or, even better, a local war in the Balkans.Footnote 80
Britain's reluctance to balance aggressively in the run up to World War I can, at least in part, be attributed to the influence of liberalism in the making of its foreign policy. Had Grey been in complete control of British policy, there is a good chance that Britain would have balanced quite aggressively against Germany.Footnote 81 His freedom of action was, however, tightly constrained by the Radical wing of the Liberal Party, which preferred to adopt an explicitly liberal approach to international politics. Keen not to upset relations with a key trading partner, Germany, the Radicals were skeptical of the entente with France and were more interested in advancing the cause of international law and promoting multilateral decision making.Footnote 82 As a result, the Foreign Secretary never gave Germany an unequivocal signal that Britain would line up against it. To be sure, he did periodically warn the Germans that London “would side with France in the event of war, but he focused most of his efforts on fostering negotiation and promoting multilateral cooperation, working through the Concert of Europe whenever possible.”Footnote 83
A similar story applies to British behavior during the July Crisis. As events unfolded, Grey considered “throwing his full support to the entente” in order to deter Germany. But he was constrained by the Radicals, who continued to have an explicitly liberal standard in mind when it came to intervention on the continent. As Kevin Narizny notes, the Radicals were not particularly worried by the “prospect that Germany would grow powerful at France's expense.” What concerned them was whether or not Germany could be trusted to behave in accordance with international law and norms once it defeated France. To their mind, “as long as Germany fought for limited aims, as it had in 1870–71, and comported itself according to the strictures of international law, it should not be considered Britain's enemy.”Footnote 84 Consequently, Britain adopted a “semi-committed diplomatic position” until Germany invaded Belgium by which time deterrence had failed.Footnote 85
In sum, there is good evidence that World War I can be attributed to Britain's failure to act as our prescriptive realism recommends. Rather than building up its power and drawing a line in the sand, Britain eschewed a military buildup and tried to conciliate Germany. As a result, deterrence failed and the Kaiserreich plunged the continent into war.
World War II
There is substantial evidence that World War II came about because Britain, France, and the Soviet Union failed to act as our prescriptive realist theory recommends. As was the case before World War I, Germany was the most powerful state in Europe. Just before the outbreak of war, it was almost twice as powerful as the Soviet Union, almost three times more powerful than Britain, and more than five times more powerful than France. Therefore, our realist recommendation would have been for Britain, France, and Russia to join forces and try to deter the Third Reich.
Rather than balancing against Germany, the other great powers frantically tried to buck-pass to each other until the outbreak of the war.Footnote 86 The French plan was to push Nazi Germany eastward in the hope that it would have to fight a long and costly war in Eastern Europe and, perhaps, the Soviet Union. France went to great lengths to make this happen, distancing itself from its East European allies in the late 1930s and even going so far as to abandon Czechoslovakia at Munich in 1938. At the same time, the French worked hard to maintain amicable relations with Germany and consistently refused to enter into a defensive alliance with the Soviet Union. The essential goal of French policy was clear: to pass the buck to Germany's eastern neighbors.Footnote 87
For its part, the Soviet Union tried to buck-pass the burden of dealing with Germany to France and Britain. This policy was formalized in the Molotov-Ribbentrop Pact of August 23, 1939, which committed Germany and the Soviet Union to remain neutral in the event that the other was attacked by a third party. As Mearsheimer notes, signature of the pact “virtually guaranteed that Hitler would go to war with the United Kingdom and France while the Soviet Union sat out the fight.”Footnote 88 The policy worked: Germany attacked France on May 10, 1940.
Britain also failed to balance, seriously ramping up defense spending only in 1938. Until that point, the Cabinet consistently accepted recommendations from the Treasury to scale down proposals to increase the defense budget even though Germany spent at least twice as much of its GNP on its military as did Britain.Footnote 89 And rather than drawing a line in the sand, London sought to improve its relations with Nazi Germany. According to Randall Schweller, “Interwar British defense policies provide an exemplary case of poor strategic adjustment in the form of overly cooperative behavior in response to an increasingly threatening external environment.”Footnote 90 Between 1936 and 1938 alone, Britain acquiesced to Nazi Germany's military reoccupation of the Rhineland, its annexation of Austria, and its acquisition of the Sudetenland.Footnote 91 In other words, rather than balancing, Britain pursued a “disarmament and cooperative peace strategy.”Footnote 92
It is worth noting that the United States—the other great power that had an interest in preventing Germany from dominating Europe—also made no attempt to balance. The Roosevelt administration openly sided with Britain only after the fall of France in 1940, and was domestically constrained from entering the war until the Pearl Harbor attacks broke the political deadlock over intervention.Footnote 93
This widespread balancing failure emboldened Hitler and made World War II more likely. Although Nazi Germany was the most powerful state in Europe, it was considerably weaker than a British-French-Soviet combination. Therefore, the other great powers might have been able to deter Germany if they had come together and presented a united front. Indeed, there is some evidence that Hitler feared a repeat of World War I and believed he could prevail only if he kept his potential victims divided.Footnote 94 As it happened, however, Britain, France, and the Soviet Union refused to form a countervailing alliance. Crucially, Hitler was not confronted with the prospect of a two-front war, perhaps the only situation that might have deterred him. As a result, a German bid for hegemony was all but assured in the late 1930s.
At first glance, there seems to be some evidence that contradicts our interpretation of events. Norrin Ripsman and Jack Levy, for example, argue that British appeasement was intended to buy time for rearmament, delaying war until Great Britain was better prepared for it. To their mind, appeasement is better seen as a complement than an alternative to balancing.Footnote 95 The problem with this view is that Britain only needed to buy time because it had pared defense spending to the bone after World War I and was slow to ramp it up even after decision-makers became convinced that war with Germany was a real possibility. Even when the British did accelerate their rearmament effort, spending was skewed toward the Royal Air Force and the Royal Navy, which facilitated passing the buck to France but did little to contain Germany on the continent.Footnote 96 In other words, it is difficult to square Britain's appeasement policy with our balancing logic.Footnote 97
Although it was not the only factor, liberalism contributed to this deterrence failure in two ways. First, their liberal commitments meant that Britain and France were reluctant to form an alliance with a communist Soviet Union. As P.M.H. Bell notes in his history of the origins of World War II, although “calculations of power politics” pointed toward an alliance with the Soviet Union, these were overwhelmed by “a deep seated hostility to Bolshevism which encouraged some sympathy for Nazism and fascism in both countries.” This, in turn, “left an easy path for the advance of Germany … beyond any point where it might have been resisted without large-scale war.” Second, their preference for liberal solutions inclined Britain and France to work through international institutions rather than attend to the balance of power. “The prevalent attitude in both countries,” explains Bell, “was a combination of a widespread revulsion against war, attachment to the League of Nations, and support for disarmament. This outlook made war almost unthinkable; and it did much to explain why France and Britain acquiesced for so long in the advance of German power, to the point where it probably could not be checked without war.”Footnote 98
The Vietnam War
The US decision to prosecute the Vietnam War directly contravenes the dictates of our theory. Because Vietnam was a minor power, and a weak one at that, its loss to the communist bloc would have done almost nothing to improve the power position of the Soviet Union, or China for that matter, nor would it have harmed the power position of the United States. Vietnam revisionists, those who believe the war was necessary, concede as much. According to Gary Hess, their position is that “Vietnam was important not because of its resources or for economic considerations, but because both sides in the Cold War had been drawn into its internal struggle.”Footnote 99 Given the limited material stakes, our theory would have counseled against becoming militarily involved in the struggle in Indochina.
It was precisely on these grounds that Waltz opposed the war at the time. To his mind, the United States could not be fighting out of necessity, as the balance of power was not at stake; referring to liberation movements like the Viet Cong, he observed that “the revolutionary guerilla wins civil wars, not international ones, and no civil war can change the balance of world power unless it takes place in America or Russia.”Footnote 100
In spite of these comments, many contemporary analysts argued that the Vietnam War was, at root, a realist one. Anthony Lake and Roger Morris, for example, asserted that the United States had sent “men to die for intangible and often transient notions of international balances of power.”Footnote 101
It is true that decision makers invoked balance of power concerns to justify the war, declaring that the loss of Vietnam to communism might lead to the loss of all of Southeast Asia. As first articulated by President Dwight Eisenhower, the “domino theory” held that if communists took over Vietnam they would be able to do the same to Cambodia, Laos, Thailand, Malaya, and Indonesia. As a result, the balance of power would shift in favor of the communist bloc.Footnote 102
Although it focused on the balance of power, the domino theory was not a realist argument. Because the dominoes were minor powers, their loss would have had little meaningful effect on the balance of power. The numbers bear out this claim: had all the dominoes joined the communist bloc, this would have increased its power by roughly one percent.Footnote 103 Put slightly differently, Southeast Asia was not a strategically important region. Therefore, the realist policy would have been to avoid military involvement there. Jerome Slater concludes as much, arguing that “communist domination over Southeast Asia was not a sufficient threat to vital U.S. interests or national security to justify a major war.”Footnote 104 It is also worth noting that the domino theory itself was flawed; it overestimated the cohesive effects of communist ideology, traded on an unsophisticated conception of the revolutionary process, and contained the seeds of its own falsification—that is, when one domino fell, the others could undertake a variety of preventive measures to ensure that they would not be next.Footnote 105
If there was no balance-of-power reason for fighting in Southeast Asia, why did the United States become embroiled in the Vietnam War? A number of factors were doubtless at work, but an ideological aversion to communism, rooted in liberalism, was one of the most important. The fact is that American decision makers fixated on the communist aspect of the challenge in Vietnam, dismissing the nationalist credentials of their opponent and escalating the war despite the meager material stakes. Jeffrey Record puts the point well: “Policymakers were wont to equate communism in the 1950s and 1960s with fascism in the 1930s and 1940s and any refusal to stand and fight to prevent communism's spread anywhere as tantamount to a Munich-style act of appeasement…. Unfortunately, those responsible for America's Vietnam intervention had come to believe that communist expansion anywhere, even in strategically remote areas against unsavory noncommunist dictatorships, threatened U.S. security.”Footnote 106 Vietnam was, in short, a case of anticommunism run amok. This was how Hans Morgenthau, a realist, saw things at the time, describing US policy as an “indiscriminate crusade against communism.”Footnote 107
The Iraq War
Following the September 11, 2001 attacks on the United States, the George W. Bush administration decided that the danger posed by Saddam Hussein's Iraq was no longer tolerable. The containment regime that had been put in place in the 1990s was crumbling, and as soon as sanctions were lifted, Iraq could rapidly reconstitute its weapons of mass destruction capability. Once in possession of such weapons, Saddam would be in a position to blackmail his neighbors or, more worrisomely, pass them off to terrorists who would not hesitate to use them against the American homeland. Since terrorists and rogue states could not be deterred, the administration felt that a policy of containment was no longer adequate. Regime change was warranted, even if that required preventive war. By deposing Saddam, the United States would not only remove a threat to its security but would also spread democracy in the Middle East, thereby undermining the climate of extremism that had produced 9/11.
Had the Bush administration adhered to the prescriptions of our version of realism, it would have contained Iraq rather than going to war. The reason is that Iraq was a minor power, albeit one located in a strategically important region of the world. Given this state of affairs, all the United States had to do was make its interests clear and draw a line in the sand.
Realists made exactly this case at the time, arguing that instead of attacking Iraq, the United States should contain it. This argument first appeared in an advertisement that over thirty security studies scholars—many of them realists—took out in the New York Times on September 26, Reference Art2002. One of their core claims was that Iraq was eminently deterrable: “Even if Saddam Hussein acquired nuclear weapons, he could not use them without suffering massive U.S. or Israeli retaliation.” Therefore, the advertisement concluded, “the United States should maintain vigilant containment of Iraq,” but not invade it.Footnote 108
Mearsheimer and Walt, both of whom signed the advertisement, elaborated the argument in the pages of Foreign Policy and the New York Times. In a straightforward application of realist logic, they argued that “both logic and historical evidence suggest a policy of vigilant containment would work, both now and in the event Iraq acquires a nuclear arsenal.” Why? “Because the United States and its regional allies are far stronger than Iraq.”Footnote 109 Indeed, to strengthen their case, Mearsheimer and Walt pointed to the fact that “today, Iraq is weakened, its pursuit of nuclear weapons has been frustrated, and any regional ambitions it may once have cherished have been thwarted.” The bottom line: “Saddam Hussein needs to remain in his box—but we don't need a war to keep him there.”Footnote 110
If realist logic pointed away from war with Iraq, why was the Bush administration so taken with the idea? A number of analysts have noted that ideological considerations were paramount, as neoconservativism powerfully shaped official thinking in the wake of the 9/11 attacks and underpinned the decision to invade Iraq.Footnote 111 Neoconservativism, as embodied in the Bush Doctrine, had four elements: an advocacy of American hegemony, an openness to the preventive use of force, a willingness to act unilaterally when necessary, and a commitment to democracy promotion.Footnote 112 The last element is most relevant for our purposes, as it highlights the substantial overlap between neoconservativism and liberalism. Michael Desch has drawn the link explicitly, detailing the ways in which the Bush administration embraced significant aspects of the liberal tradition.Footnote 113 Bush himself, for example, was a firm believer in a generalized version of the democratic peace. As he told reporters in July 2003, “a free, democratic, peaceful Iraq will not threaten America or our friends with illegal weapons. A free Iraq will not be a training ground for terrorists, or a funnel of money to terrorists, or provide weapons to terrorists who would be willing to use them to strike our country or allies. A free Iraq will not destabilize the Middle East.”Footnote 114
Indeed, the Iraq War makes little sense in anything but neoconservative or liberal terms. As Robert Jervis argues, “the war is hard to understand if the only objective was to disarm Saddam or even to remove him from power. Even had the inflated estimates of his WMD capability been accurate, the danger was simply too remote to justify the effort. But if changing the Iraqi regime was expected to bring democracy and stability to the Middle East, discourage tyrants and energize reformers throughout the world, and demonstrate the American willingness to provide a high degree of what it considers world order whether others like it or not, then as part of a larger project, the war makes sense.”Footnote 115
Case Summary
Two features of the cases bear elaboration. For starters, the evidence suggests that the great powers might have become involved in fewer wars if they had acted on the basis of our prescriptive realist theory. Germany might have been deterred from initiating the world wars, and the United States might not have become embroiled in Vietnam and Iraq.
At the same time, liberalism appears to be implicated in each of the wars. In the world war cases, their commitment to pursuing a liberal foreign policy meant that Britain and France failed to balance aggressively enough to deter Germany. Meanwhile, liberalism was a key driver of the American decision to go to war in Vietnam and Iraq.
It is important to note that these arguments are not new and that they have, in fact, been made by Michael Doyle, a prominent liberal theorist. For Doyle, liberalism has been a poor guide to foreign policy outside the liberal world, generating pathologies such as “imprudent vehemence” and a “careless and supine complaisance.”Footnote 116 The former refers, among other things, to the tendency of liberal great powers to forego mutually beneficial agreements with powerful nonliberal states—the British and French decisions not to ally with the Soviet Union before World War II are cases in point—and to succumb to “imperial interventions” against weak nonliberal states such as Vietnam and Iraq. Supine complaisance, meanwhile, refers to a reluctance to bear the costs of balancing, an attitude clearly displayed by Britain and France before the world wars.Footnote 117 In short, whatever promise liberalism may hold for ultimately transforming international politics, it often leads to foreign policy behaviors that increase the odds of war in the short term.
Conclusion
Our prescriptive realist theory is a recipe for security without war and is therefore an appropriate guide for American policy makers today. Briefly stated, the theory advises great powers to balance against peer competitors, and with the exception of hostile minor powers in strategically important areas of the world, to take a relaxed view toward states that are not great powers. Had the great powers in earlier eras consistently obeyed these injunctions, there is a good chance that they would have remained secure without having to fight many wars. But they did not adhere to these prescriptions, often because they were inclined to pursue a liberal foreign policy. As a result, they put their security at risk and ended up fighting more wars than they had to.
We conclude by addressing two questions begged by the preceding analysis. First, how problematic is it for realism as a descriptive theory that its prescriptions are regularly violated? Ido Oren identifies a tension between realist theory and practice, what he calls the “theory-practice paradox.”Footnote 118 On the one hand, realists claim to capture the world as it really is in their theorizing. On the other hand, they frequently intervene in public debates, like the one preceding the Iraq War. If state behavior is driven by external constraints and opportunities, as realists claim, it is not clear what this advocacy is supposed to accomplish. Moreover, when they criticize US foreign policy, realists are tacitly conceding that their expectations have not been met and that their theories are not as powerful as advertized. In short, when realists engage in public activism, they expose a serious disconnect between their theory and practice.
Upon close inspection, the theory-practice paradox is more apparent than real. The tension between realist theory and practice disappears as soon as one appreciates that descriptive realist theories, like all theories of international relations, are probabilistic and therefore that states will sometimes act in ways that contradict realist expectations. In those cases, realists are entitled to advocate for their preferred courses of action. It was Waltz himself, the scholar most associated with structural realism, who insisted that systemic pressures shape and shove rather than determine state behavior.Footnote 119 His is a theory of international politics, after all, not one of foreign policy; it is designed to explain international outcomes, not the behavior of individual states.Footnote 120 In those few cases where a state's policy departs from what structural realism would predict, we should find that domestic politics and ideology are to blame and that the state pays a stiff price for its non-realist behavior.Footnote 121 This is what we find in the historical evidence. More generally, this is the research agenda that neoclassical realists have pursued, exploring the domestic-political and ideological roots of sub-optimal behaviors such as overexpansion and underbalancing.Footnote 122
Second, what policy would our theory recommend for the United States today? It would advise the US to balance against other great powers and to take a relaxed attitude toward minor powers. The exception would be when a minor power is situated in a strategically important region of the world, in which case it would prescribe vigilant containment. These injunctions are similar to those that fall under the rubric of “offshore balancing,” a grand strategy favored by many realists.Footnote 123
What would such a policy look like in practice? Perhaps most important, it would involve balancing against China in the event that it emerges as a peer competitor to the United States. In other words, if China were to continue to grow economically, convert its wealth into military power, and show any sign of wanting to use that power to dominate Asia, then we would recommend that the United States balance against it internally and externally. Internal balancing would mean deploying sufficient military forces—especially air and naval assets—to the region to frustrate any aggressive Chinese designs. External balancing would be accomplished by cementing alliances with China's strongest neighbors, including India, Japan, and Russia. War need not result so long as the United States makes it clear that it will not tolerate military adventurism while accommodating a growing economic and diplomatic role for China.Footnote 124
As for policy toward Iran—the most pressing minor power challenge—our theory counsels restraint. Iran, like Iraq before it, is a leading player in a strategically important region, but it has little power projection capability and would be incapable of dominating the Persian Gulf even if it were to acquire nuclear weapons, which are useful for little more than deterrence. To paraphrase Barry Posen, Washington can live with a nuclear Iran.Footnote 125 Of course, the United States should keep a watchful eye on Iran and vigorously deter rash actions on its part. Indeed, in the event that Iran acquires the bomb, a containment regime would be warranted: the US should make it clear to Iran that it will not tolerate aggression of any kind, be it conventional or nuclear.Footnote 126 Given the power disparity between the two sides, containment should be a straightforward matter, and it would be preferable to a preventive war that would at best delay Iran's acquisition of nuclear weapons while inviting almost certain retaliation.Footnote 127
If the United States acts in a realist fashion and adheres to these prescriptions, then it is likely to remain secure for the foreseeable future and it will be able to do so without becoming involved in any major wars. To be sure, it will compete for security, but armed conflict is improbable. If it succumbs to its liberal inclinations, on the other hand, then all bets are off.
