Jeffrey W. Taliaferro

Does the international system provide incentives for expansion? If so, should the United States seek to guarantee its long-term security through a grand strategy of preponderance (or primacy) and pursue opportunities to weaken potential great power competitors, such as China? Alternatively, does the international system provide more disincentives than incentives for aggression? If this is the case, should the United States seek to guarantee its long-term security through a grand strategy of selective engagement? Two strands of contemporary realism provide different answers to these questions.

Offensive realism holds that anarchy—the absence of a worldwide government or universal sovereign-provides strong incentives for expansion.? All states strive to maximize their power relative to other states because only the most powerful states can guarantee their survival. They pursue expansionist policies when and where the benefits of doing so outweigh the costs. States under anarchy face the ever-present threat that other states will use force to harm or conquer them. This compels states to improve their relative power positions through arms build ups, unilateral diplomacy, mercantile (or even autarkic) foreign economic policies, and opportunistic expansion."

Defensive realism holds that the international system provides incentives for expansion only under certain conditions. Under anarchy, many of the means a state uses to increase its security decrease the security of other states. This security dilemma causes states to worry about one another's future intentions and relative power. Pairs of states may pursue purely security-seeking strategies, but inadvertently generate spirals of mutual hostility or conflict. States often, although not always, pursue expansionist policies because their leaders mistakenly believe that aggression is the only way to make their states secure. Defensive realism predicts greater variation in internationally driven expansion and suggests that states ought to generally pursue moderate strategies as the best route to security. Under most circumstances, the stronger states in the international system should pursue military, diplomatic, and foreign economic policies that communicate restraint.

 Defensive realism has recently come under attack from critics of realism and even from fellow realists. Critics of realism, such as Andrew Moravcsik and Jeffrey Legro, fault various defensive realist theories for positing a role for domestic politics, elite belief systems and misperceptions, and international institutions. By including such variables in their theories, the critics argue, defensive realists effectively repudiate the core assumptions of political realism. Offensive realists, such as Fareed Zakaria and Randall Schweller, charge that defensive realism cannot explain state expansion because it argues that there are never international incentives for such behavior.

I argue that the debate between defensive realism and offensive realism over the implications of anarchy and the need to clarify defensive realism's auxiliary assumptions deserve attention for three reasons. First, the outcome of this theoretical debate has broad policy implications. Defensive realism suggests that under certain conditions, pairs of nondemocratic states can avoid war, states can engage in mutually beneficial cooperation without the assistance of international institutions, and norms proscribing the development and use of weapons of mass destruction are largely epiphenomenal.' In addition, offensive realism and defensive realism generate radically different prescriptions for military doctrine, foreign economic policy, military intervention, and crisis management.

Second, debates within particular research traditions, not debates between them, are more likely to generate theoretical progress in the study of international politics. By developing and testing theories derived from the same core assumptions, researchers can more easily identify competing hypotheses, refine scope conditions for theories, and uncover new facts. Arguably, this is a more productive strategy for the accumulation of knowledge than the current tendency among some scholars to brand entire research programs as "degenerative." As Robert Jervis observes: "Programs—and, even more, their first cousins, paradigms—are notoriously difficult to confirm or disconfirm. Not only do they shape what counts as a fact at all, but also there are so many steps between assumptions and outlooks on the one hand and empirical findings on the other that neither in social nor in natural sciences can the evidence ever be unambiguous."

Third, regardless of whether realism is the dominant theoretical approach in international relations, it remains the bête noire of every nonrealist approach. Proponents of neoliberal institutionalism, various cultural theories, democratic peace theories, and constructivism all begin with the supposition that realism is an extremely limited, if not completely bankrupt, body of theory.In the interest of scholarly dialogue, it is important to clarify the predictions of particular realist theories.

I argue that defensive realism proceeds from four auxiliary assumptions that specify how structural variables translate into international outcomes and states' foreign policies. First, the security dilemma is an intractable feature of anarchy. Second, structural modifiers—such as the offense-defense balance, geographic proximity, and access to raw materials influence the severity of the security dilemma between particular states. Third, material power drives states' foreign policies through the medium of leaders' calculations and perceptions. Finally, domestic politics can limit the efficiency of a state's response to the external environment.

The first section of this article discusses the debates within contemporary realism, drawing a distinction between theories of international politics (neorealism) and theories of foreign policy (neoclassical realism), both of which have defensive and offensive variants. I divide realism along these lines because doing so allows us to distinguish between debates over the implications of anarchy and the empirical range of particular theories. The second section examines the four assumptions underlying the defensive variants of neorealism and neoclassical realism. The third section responds to several criticisms that realists and nonrealists raise about those assumptions and the explanatory power of defensive realism. The conclusion discusses the implications of the debate for U.S. grand strategy and offers some suggestions for future research.

Intra realist Debates

Realist theories share certain core assumptions, but there are two crosscutting divisions within contemporary realism. First, neorealism seeks to explain international outcomes, such as the likelihood of major war, the prospects for international cooperation, and aggregate alliance patterns among states. Neoclassical realism, on the other hand, seeks to explain the foreign policy strategies of individual states. Second, realists disagree about the logical implications of anarchy. This is the crux of the debate between offensive realism and defensive realism. Below I discuss the four categories of realist theory and how the offensive-defensive dichotomy transcends the distinction between neorealism and neoclassical realism.

NEOREALISM AND NEOCLASSICAL REALISM

Neorealism and neoclassical realism differ based on the phenomena each seeks to explain, or the dependent variable. In this sense, neorealism and neoclassical realism are complementary; each purports to explain phenomena that the other does not.

Neorealism is a body of international relations theory that builds upon a few assumptions about the international system and the units that it comprises. Neorealist theories seek to explain international outcomes-phenomena that result from the interaction of two or more actors in the international system. For example, explaining the likelihood of major or hegemonic war falls within the purview of neorealism. Other examples of international outcomes include international cooperation, arms races, crisis bargaining, aggregate alignment patterns, and the war proneness of the international system. In short, one cannot attribute these phenomena to the behavior of any one state.

Neorealism cannot make predictions about the foreign policy behavior of individual states. It cannot, for example, answer the following question: What will a particular state faced with these circumstances likely do? As Kenneth Waltz observes, a strictly systemic theory "can tell us what pressures are exerted and what possibilities are posed by systems of different structure, but it cannot tell us just how, and how effectively, the units of a system will respond to those pressures and possibilities."l' Waltz's balance-of-power theory is the most prominent example of the neorealist approach. Neorealism also encompasses hegemonic theories of war and change, power transition and long cycle theories, and systems theory.

Neoclassical realism seeks to explain why different states or even the same state at different times pursues particular strategies in the international arena. It generates probabilistic predictions about how individual states respond to systemic imperatives. Phenomena such as individual states' grand strategies, military doctrines, foreign economic policy, alliance preferences, and crisis behavior fall within neoclassical realism's purview. Neoclassical realism cannot predict the aggregate international consequences of individual states' strategies.

While building on Waltz's assumptions about anarchy, neoclassical realists explicitly reject the injunction that theories ought not to include explanatory variables at different levels of analysis. Gideon Rose notes that a state's relative material capabilities set the parameters of its foreign policy. He observes, however, "that the impact of such power capabilities on foreign policy is indirect and complex, because systemic pressures must be translated through intervening variables at the unit level."

OFFENSIVE REALISM VERSUS DEFENSIVE REALISM

Whereas neorealism and neoclassical realism seek to explain different phenomena, the divide between offensive realism and defensive realism represents a fundamental divergence on the implications of anarchy. Thus offensive realism and defensive realism are theoretical competitors because they generate different predictions and policy prescriptions. This division subsumes the neorealist-neoclassical dichotomy.

 Table 1 illustrates how the offensive realism-defensive realism debate cuts across the divide between neorealism and neoclassical realism. This two-part classification scheme refers to particular theories, not particular theorists. Specific theories fall into these categories, but scholars may work in more than one category.

Auxiliary Assumptions of Defensive Realism

Four auxiliary assumptions define defensive realism. The first two specify the incentives for interstate conflict or cooperation. The latter two specify the links between external forces and the actual foreign policy behavior of individual states.

 

 

ASSUMPTION 1: THE INTRACT ABILITY OF THE SECURITY DILEMMA

The security dilemma is an intractable feature of the international system. Jervis defines the security dilemma as a situation "in which the means by which a state tries to increase its security decreases the security of others." Anarchy produces uncertainty, and states can never be certain of others' present or future intentions or the relative distribution of capabilities over time. Anarchy induces states to engage in self-help behavior. States react to reductions in their security by taking steps to increase their own security, thus mitigating the security policies of others.

Why should the efforts of one state to make itself secure cause other states to feel less so? Charles Glaser posits three ways through which making one's adversaries insecure can prove self-defeating. First, even security-seeking policies can set in motion a process that reduces the state's own military capabilities—the ability to perform particular military missions. Second, selfhelp strategies may increase the value an adversary places on expansion as a means of self-defense, which in turn makes deterrence harder. Third, both military buildups and alliances can change the adversary's beliefs about the state's motives, thus convincing the adversary that the state is inherently more dangerous than previously thought. An adversary may conclude that a state harbors "greedy” motives—that is, a desire to expand for reasons other than security. Arms buildups may simply be a waste of a state's finite resources, because others may be able to meet or exceed its level of armament. In short, a state that initiates a military buildup to increase its security may inadvertently set in motion a chain of events that leaves it less secure.

ON 2: STRUCTURAL MODIFIERS AND THE SECURITY DILEMMA

The security dilemma is inescapable, but it does not always generate intense competition and war. In addition to the gross distribution of power in the international system, other material factors, which I refer to as "structural modifiers," may increase or decrease the likelihood of conflict.

 These include the offense-defense balance in military technology, geographic proximity, access to raw materials, international economic pressure, regional or dyadic military balances, and the ease with which states can extract resources from conquered territory.

Defensive realists assume that structural modifiers have a greater influence on the likelihood of international conflict or cooperation than does the gross distribution of power. The gross distribution of power refers to the relative share of the international system's material capabilities that each state controls. Polarity, or the number of great powers in the international system, is the most common measure of the gross distribution of power. Structural modifiers, on the other hand, refer to the relative distribution of capabilities that enable individual states to carry out particular diplomatic and military strategies. This in turn influences the severity of the security dilemma between particular states or in regional subsystems. Thus one may think of the structural modifiers as mediating the effects of systemic imperatives on the behavior of states.

Consider, for example, offense-defense theory and balance-of-threat theory. It makes little sense to speak of a systemwide offense-defense balance in military technology. The possession of particular military technologies and weapons systems influences the relative ease with which a state can attack or hold territory. The objective offense-defense balance affects the strategies of individual states and the interaction between pairs of states; it does not change the gross distribution of power in the international system. Similarly, balance-ofthreat theory does not posit that states always balance against the greatest threat in the international system. Rather they generally balance against states that pose an immediate threat to their survival.

Defensive realism, in both its neorealist and neoclassical realist variants, challenges notions that the security dilemma always generates intense conflict. In this respect, defensive realism corrects deductive flaws both in Waltz's core model and in offensive realism. Waltz holds that anarchy and the need for survival often force states to forgo mutually beneficial cooperation. At a minimum, cooperation is difficult because states are sensitive to how it affects their current and future relative capabilities. Cooperation often proves to be impossible, particularly in the security arena, because states have every incentive to maintain an advantage over their competitors. Some offensive realists go further in arguing that cooperation can put a state's survival in jeopardy. John Mearsheimer argues that anarchy leaves little room for trust because "a state may be unable to recover if its trust is betrayed."

Defensive realism faults these arguments for being incomplete. Cooperation is risky, but so is competition. States cannot be certain of the outcome of an arms race or war beforehand, and losing such a competition can jeopardize a state's security. Waltz's balance-of-power theory and Mearsheimer's offensive realism require that states evaluate the risks of cooperation and competition, but they do not explain variation in competitive or cooperative behavior. This has implications for both foreign policy and international outcomes.

The defensive variants of neorealism and neoclassical realism specify the conditions under which cooperative international outcomes and less competitive state behavior, respectively, become more likely. According to offensedefense theory proponents, at the operational and tactical level, improvements in firepower (e.g., machine guns, infantry antitank weapons, surface-to-air missiles, and tactical nuclear weapons) should favor the defense because attackers are usually more vulnerable and detectable than are well-prepared defenders. At the strategic level, the anticipated high costs and risks of conquests should deter even greedy leaders.

The nuclear revolution-specifically the development of secure secondstrike capabilities by the declared nuclear states-provides strong disincentives for intended war. This does not mean that pairs of nuclear-armed states will not engage in political-military competition in third regions or limited conventional conflict short of all-out war. Rather it suggests that intended (or premeditated) wars—wars that break out as the result of a calculated decision by at least one party to resort to the massive use of force in the pursuit of its objectives—become highly unlikely. Conversely, if the offense dominates, then states have an incentive to adopt aggressive strategies. Similarly, states' abilities to extract resources from conquered territory influence the likelihood of international conflict. Where industrial capacity, strategic depth, or raw materials are cumulative, defensive realists would expect states to pursue expansionist policies.

According to Mearsheimer, states must constantly worry about their survival because potential competitors may try to eliminate them at any time. He argues, "States operate in both an international political environment and an international economic environment, and the former dominates the latter in cases where the two come into conflict." This implies that states will heavily discount the future by favoring short-term military preparedness over longerterm objectives, such as economic prosperity, when and if the two goals conflict.

Again, defensive realism finds this argument lacking and specifies the conditions under which states are more likely to heavily discount the future and prefer short-term military preparedness to long-term economic prosperity. For example, where geography provides defense from invasion or blockade, defensive neoclassical realism would expect a state to favor long-term objectives. Similarly, a state with relatively weak neighbors can afford to take a longerterm perspective and devote a greater portion of its national resources to domestic programs. A relatively benign threat environment removes the incentives for the development of strong central institutions within the state. For example, geographic separation from Europe and the relative weakness of Canada and Mexico allowed the United States to survive the first 150 years of its independence without developing strong state institutions (i.e., a large standing army, an efficient tax system, and a large central bureaucracy).

There are several circumstances, however, where defensive realism expects states to favor short-term military preparedness over long-term economic prosperity. States that lack defensible borders or have strong neighbors will have a powerful incentive to build strong central institutions, maintain large standing armed forces, and adopt offensive military doctrines. The rise of Prussia is the classic example of how a precarious threat environment influences both a state's grand strategy and the development of its domestic political institutions. The original Hohenzollern territories were noncontiguous and lacked defensible borders. External vulnerability provided strong incentives for the development of efficient state institutions to extract resources from domestic society, a standing army, and a preference for offensive military doctrines. Successive Prussian kings, most notably Frederick the Great, tried to acquire, through opportunistic expansion and shrewd alliances, additional territories needed to consolidate and round off the kingdom's borders.

Likewise, when the offense-defense balance favors the offense or if a state lacks defensible borders, one should expect that state to adopt a very shortterm perspective when faced with a rising external threat. This in turn may cause states to engage in truncated or hasty diplomacy, conceal grievances, adopt offensive military force postures, and seize first-move advantages.

ASSUMPTION 3: THE INFLUENCE OF MATERIAL CAPABILITIES ON FOREIGN POLICY

Defensive neoclassical realists assume that in the short run, the relative distribution of power is often uncertain and leaders often face ambiguous and contradictory information. Therefore such foreign policy theories posit an explicit role for leaders' preexisting belief systems, images of adversaries, and cognitive biases in the process of intelligence gathering, net assessment, military planning, and foreign policy decisionmaking. Much of what defensive neoclassical realists seek to explain would be simply inexplicable without reference to the perceptions of central decisionmakers.

The role of such perceptional variables becomes particularly important during periods of rapid power fluctuation.48 They also play an important role during noncrisis periods and periods when the distribution of power remains relatively stable. Benjamin Miller finds that benign images of the opponent, balancing beliefs, and ideological similarity, along with multipolarity and common fears of revolution, are necessary conditions for the emergence of great power concerts.

Finally, leaders' perceptions play a critical and at times pernicious role in shaping how states respond to the structural modifiers. Often the "objective" offense-defense balance is sharply at odds with civilian and military leaders' perceptions of it. Officials often draw upon the "lessons of history" in formulating military doctrine or allow organizational priorities to override legitimate security requirements.51 The most oft-cited instance in which this happened is the "cult of the offensive" among the European great powers before World War 1. ASSUMPTION 4: DOMESTIC POLITICS AND SYSTEMIC IMPERATIVES

The defensive variant of neoclassical realism posits a role for domestic politics in shaping states' foreign policies. Furthermore, defensive neoclassical realism specifies the conditions under which domestic politics matters in foreign policy. For example, during periods of imminent external threat, the calculations of central decisionmakers are paramount. Over the longer term or in the absence of an immediate external threat, national leaders will have more difficulty in mobilizing domestic resources for foreign policy. Furthermore, leaders' mobilization efforts may later restrict their ability to readjust their foreign policies in response to changes in the external environment.

Thomas Christensen's domestic mobilization theory addresses the problem of how domestic politics constrains states' abilities to adjust their foreign policies. In the late 1940s and 1950s, U.S. and Chinese leaders sought to mobilize domestic resources to balance against the Soviet Union, but lacked sufficient "national political power" to do as they pleased. President Harry Truman and Chairman Mao Zedong used domestically popular but unnecessary foreign policies in secondary areas as a diversion for necessary but unpopular policies in primary areas. These secondary policies set in motion a chain of events culminating in the U.S. and subsequent Chinese interventions in the Korean War and the 1958 Quemoy-Matsu crisis.

Defensive neoclassical realism relies on a top-down conception of political behavior and rejects liberalism's assumption that the fundamental actors in international politics are risk-averse, rational individuals or groups within society. Leaders weigh options and make decisions based primarily on their strategic situation and an assessment of relative power. State autonomy vis-àvis civil society, organizational politics, and civil-military relations, however, can constrain the efficiency of leaders' responses to systemic imperatives. For example, state strength (i.e., the extractive capacity of a state's central political institutions) influences both the amount of military power a state can project abroad and the scope of its grand strategy.

Consider the grand strategies of the superpowers during the Cold War. Aaron Friedberg argues that while the gross distribution of power and structural modifiers pushed the United States and the Soviet Union toward confrontation, internal factors shaped the types of strategies each side pursued. In the U.S. case, a combination of weak state institutions, the material interests of various societal actors, and an embedded antistatist ideology eventually led to the adoption of a flexible response strategy and a limited program of power creation. The Soviet Union, on the other hand, lacked all of the countervailing domestic influences. As a result, during most of the Cold War, the Soviet Union pursued a more ambitious military doctrine (i.e., full war fighting) than did the United States and undertook a far more expansive program of power creation.

Criticisms of Defensive Realism

The four auxiliary assumptions discussed above define defensive neorealism and defensive neoclassical realism. Recently, however, both nonrealists and offensive realists have raised several theoretical and empirical critiques of each. The following section examines the most prominent critiques and concludes that most proceed from incomplete or flawed analysis.

CRITICISM 1: THERE IS NO SECURITY DILEMMA Randall

Schweller challenges the existence of the security dilemma and faults Waltz for allegedly relying on uncertainty, instead of structure, to explain international conflict and balancing. He writes, "Predatory states motivated by expansion and absolute gains, not security and the fear of relative losses, are the prime movers of neorealist theory. Without some possibility of ... [the] existence (of predatory states], the security dilemma melts away, as do most concepts associated with contemporary realism."

Schweller contends that balancing would not occur in an international system comprised entirely of security-seeking states, unless states were uncertain of one another's motives. He argues that if all states seek security,"the security dilemma is always apparent, not real." If aggressors (i.e., states that arm for nonsecurity reasons) do exist, then there would be no security dilemma "but rather an example of a state or coalition mobilizing for the purpose of expansion and targets of that aggression responding by acquiring arms and forming alliances to defend themselves." If, on the other hand, real aggressors do not exist, this reliance on uncertainty to explain war and balancing behavior violates "realism's most basic tenet that conflicts of interest among states are genuine rather than the result of misunderstanding and misperception."

Schweller's critique of the security dilemma misses the mark in three respects. First, he fails to appreciate the role that uncertainty plays in both Waltz's balance-of-power theory and defensive neorealism. Glaser notes that neorealism assumes that states are black boxes "that provide no information about internal differences, except for the observable outputs of their international policy choices."61 States do not rely on the internal characteristics of other states for

-for example, their political or economic systems—to discern their motives. Instead, they must draw inferences from observable international behavior. Nevertheless, when a state faces a security dilemma, many policies that would improve the state's security also send ambiguous information about motives.

Second, states face real uncertainty not only about one another's present motives but also about their future motives and relative capabilities. States can never be certain of one another's future intentions, regardless of whether they harbor "greedy" or "security-seeking" motives in the present. Uncertainty about the future and anticipated shifts in the relative distribution of power create incentives and dişincentives for cooperative or competitive policies in the present. Windows of opportunity tempt declining states to contemplate war before the power shift is complete. For example, in the late 1940s and early 1950s, the loss of its nuclear monopoly and the development of thermonuclear weapons created a window of opportunity for the United States. Preventive war arguments were common within the Joint Chiefs of Staff and the Truman administration. Few scholars, however, would classify the United States as harboring greedy motives.

Third, Schweller ignores the incidence of security-driven expansion in world history. The historical record abounds with cases of states that pursued security-driven expansion or preventive war. This is not to say that defensive realists deny the existence of predatory states; in fact, they do not. Few defensive realists would classify the expansionist behavior of Napoleonic France and Nazi Germany as security driven.

CRITICISM 2: GREEDY STATES AND INTERNATIONAL CONFLICT

Andrew Kydd argues that greedy states, not the security dilemma, are the permissive cause of international conflict and balancing behavior.65 He constructs a formal model in which all states are security seekers. The model assumes that all states have complete information about one another's preferences. The result would be a no-war equilibrium: States would have no incentive to arm against or attack another. This equilibrium would exist regardless of the relative distribution of power, the offense-defense balance, trends in power growth, or the cumulativity of resources. Kydd then complicates the model by adding uncertainty about future intentions. Uncertainty may undermine the no-war equilibrium, because greedy states cannot achieve their maximum payoff by not attacking.

Although states can never be completely certain of one another's present or future intentions, they do have two means to reduce uncertainty to manageable levels. First, for modern democratic states, the policymaking process is so open that they cannot help but reveal their true preferences. This transparency gives other states ample information about a democracy's greedy or securityseeking motivations. Second, all states, both democracies and nondemocracies, can employ costly signals to reveal their benign intentions. Costly signals are strategies that one type of actor in a game can take that other types might find too costly. For example, in a crisis bargaining game, a costly signal would be some act that raises the cost of backing down. Actors who have a low expected value for war or for the object at stake are more likely to send such a signal.

Kydd cites four examples of costly signals. The first is ideological moderation on the part of a state considered aggressive by others. For a leadership that truly believes in an aggressive ideology, ideological moderation has real costs. For moderate leaders, on the other hand, the costs of ideological moderation are considerably less. Second, toleration of domestic minorities can signal benign intentions, whereas leaders who oppress minorities might feel little constraint against dominating other states and peoples. Third, benign policies toward weaker neighboring states can signal security-seeking intentions. "By allowing substantial latitude and freedom within the geographical range in which it could enforce strict observance of its wishes if it chose to, the securityseeking great power signals that it is uninterested in conquest and domination for its own sake."

Finally, true security-seeking states will pursue unilateral arms control and moderate military policies. In short, greedy states are unlikely to undertake such costly signals.

Defensive realists would agree with some aspects of Kydd's model, but they would disagree with the broad conclusions he draws from it. For example, in relations with their weaker neighbors, states can and do employ arms control, defensive military doctrines, force postures, and moderate policies. Such actions can only mitigate, but not eliminate, the security dilemma. Like Schweller, Kydd underestimates the difficulty of discerning states' future intentions and power trends: "With respect to fears about future motivations, while they are conceivably able to motivate conflict and war, they have historically rarely done so. It is difficult to explain many historical arms races or wars as a result of fears about the possible future preferences of a current benign regime." On the contrary, the Peloponnesian War, the War of the Spanish Succession, the Seven Years' War, the French Revolutionary Wars, Russia's mobilization in the July 1914 crisis, the 1962 Sino-Indian War, the 1965 and 1971 Indian-Pakistani Wars, and the 1990 Kashmir crisis are all cases where security-seeking states precipitated international crises or wars in part because of uncertainty about adversaries' intentions and impending power shifts.

Japan's expansion in the 1930s and early 1940s and China's intervention in the Korean War are classic cases of how security-driven policies and fears of adversaries' future intentions can provoke conflict. The notion that Japan could best provide for its security through empire and autarky originated in the lessons that its military planners drew from Germany's defeat in World War I. If future conflicts resembled that war, a state's ability to win would depend largely on its ability to mobilize economic resources. The Japanese home islands, however, lacked the natural resources needed to fight a prolonged war, which in turn made Japan vulnerable to exploitation or attack from the United States, the Soviet Union, the Netherlands, or Great Britain. To that end, elements of the Japanese Imperial Army pursued a measured expansionist strategy in resource-rich Manchuria and northern China from 1931 to 19373 Japanese perceptions of vulnerability and inevitable hostility from the West and the Soviet Union dominated decisionmaking within Japan's army and naval general staffs and the cabinets of successive prime ministers-Prince Konoe Fumimaro, Baron Hiranuma Kiichiro, Gen. Abe Nobuyuki, Adm. Yonai Mitsumasa, and finally Gen. Tojo Hideki.

The July 1937 clash between Japanese and Kuomintang (KMT or Chinese Nationalist) troops near Beijing's Marco Polo Bridge escalated into a full-scale war between Japan and the forces of Chiang Kai-shek. The so-called China Incident imposed tremendous strains on Japan's economy; increased Japan's dependence on the United States, Great Britain, and the Netherlands for oil and raw materials; and heightened tension between Tokyo and Washington. Furthermore, the Japanese Imperial Army's operations near the Sino-Soviet boarder in Manchuria brought it into direct confrontation with the Soviet army. Perceptions of vulnerability, considerations of sunk costs, and a fading window of opportunity drove the military chiefs and the Konoe and Tojo cabinets to undertake various high-risk strategies. These included Japan's expansion into the Dutch East Indies to acquire oil and raw materials; the use of diplomatic and later military means to stop the flow of arms to the KMT through French Indochina; the conclusion of the Tripartite Pact with Nazi Germany and Italy as a means to deter potential adversaries; and ultimately the decision for war with the United States.

Similarly the pursuit of security, uncertainty about the other side's capabilities and intentions, miscommunication, and misperceptions set the stage for conflict between the United States and China in the autumn of 1950. Perceptions of vulnerability, not greed, drove the Truman administration's decisions to send ground troops to the defense of South Korea following the North Korean invasion on June 25, 1950. Initially President Truman, Secretary of State Dean Acheson, and other U.S. officials sought to restore the status quo ante: a divided Korean peninsula with two sovereign states on either side of the 38th parallel. The administration escalated its war aims from containment to rollback in September, in large part to remove the perceived long-term threat to East Asian security-namely, the North Korean regime.?? Because Soviet intervention appeared unlikely and Chinese intentions and capabilities remained unclear, the Truman administration saw an opportunity to reunify Korea. At the same time, the administration did not intend to help Chiang and the KMT retake the mainland or extend the war beyond the Korean peninsula. Truman and other officials publicly made statements to that effect. Nonetheless, Gen. Douglas MacArthur's advance across the 38th parallel, along with the Truman administration's earlier decisions to send the U.S. Seventh Fleet to the Taiwan Strait, deny diplomatic recognition to the new communist regime in Beijing, and continue aid to Chiang and the KMT on Taiwan, convinced Mao that any U.S. military presence on the Korean peninsula posed a threat. In short, Chinese forces entered the Korean War because Mao feared the Truman administration's future intentions."

States may not always interpret an adversary's ideological moderation as a signal of restraint, even if concrete diplomatic moves accompany its rhetoric. Consider, for example, the Eisenhower administration's reaction to the "ideological thaw” in Soviet foreign policy following the death of Josef Stalin in March 1953. Premier Gregori Malenkov signaled a willingness to pursue détente with the United States. On March 15, he announced there was no superpower dispute that "could not be settled by peaceful means, on the basis of mutual agreement." Concrete actions followed this peace initiative, including: Soviet restoration of diplomatic relations with Yugoslavia, Greece, and Israel; the withdrawal of Soviet territorial demands on Turkey; and Soviet pressure on Beijing to end the Korean War. Nevertheless, President Dwight Eisenhower and Secretary of State John Foster Dulles saw the Soviet "peace offensive" as a tactical ploy designed to undermine popular support in the United States and among NATO allies for high defense expenditures, greater burden sharing, the development of the hydrogen bomb, and the forward deployment of U.S. troops in Western Europe. The administration responded to the Soviet peace offensive by demanding political liberalization in Eastern Europe, an Austrian neutrality treaty, and the repatriation of all German prisoners of war. Eisenhower made two nuclear disarmament proposals, the Atoms for Peace Program and the Open Skies initiative, largely to bolster the United States' image abroad and make the Soviets appear intransigent. Similarly, in 1986-87 the Reagan administration remained wary of Moscow's intentions despite General Secretary Mikhail Gorbachev's willingness to make deep (and in some cases) unilateral cuts in intermediate-range missiles and conventional forces in Europe.

Other parts of Kydd's model rely on essentially Innenpolitik arguments to challenge the existence of the security dilemma. He places considerable emphasis on domestic costly signals and the transparency of democratic systems, but claims that his model differs from the normative and institutional variants of the democratic peace thesis. In actuality, it does not. Like Kydd's generic security seekers, democratic states supposedly project internal norms of peaceful conflict resolution outwardly. This signals their benign intentions toward other democracies. This mutual recognition of shared norms for domestic conflict resolution supposedly produces a shared, but exclusive, peace among democratic states.

Defensive realism largely rejects the notion that democratic states are better able to signal intentions than are autocratic states, because the multiplicity of parties, actors, and interest groups within a democratic state can send mixed messages about its intentions. Again, there are many historical cases where potential adversaries misjudged the supposedly security-seeking preferences of democracies or where democracies failed to communicate their intentions. During the July 1914 crisis, Britain did not clearly signal its resolve to support France and Russia and protect Belgian neutrality until July 28–29, by which time the crisis was out of control. The Japanese government and military chiefs of staff in 1940-41 failed to discern the Roosevelt administration's true security-seeking preferences, despite the supposed transparency of the U.S. political system. Similarly, throughout the Cold War, Soviet leaders viewed their counterparts in Washington as expansionist and irredeemably hostile (and vice versa). Nor are these miscalculations limited to nondemocratic states. The 1898 Fashoda crisis, the 1923 Ruhr crisis, the 1861 HMS Trent affair, and three Indian-Pakistani wars are all cases where pairs of democratic states (or quasi-democratic states) miscalculated each other's security-seeking motives despite the supposed openness of the domestic political systems of the states involved.

CRITICISM 3: UNIT-LEVEL FACTORS, AGGRESSIVE BEHAVIOR, AND WAR

Fareed Zakaria claims that defensive realism cannot explain much of world politics because its adherents assert that only "pathological" states engage in expansionist behavior. Defensive realism, he argues, assumes that "security [is] plentiful" in the international system and that most states understand this.  Because states can easily obtain security through the pursuit of moderate foreign policies, only states with defective domestic political systems will pursue expansionist policies. In effect, defensive realism denies the existence of a "real" security dilemma and relies instead on unit-level variables to explain great power expansion, conflict, and war. Zakaria incorrectly claims that Waltz, Jervis, and Jack Snyder assume that all states pursue (or ought to pursue) minimal security. He writes, "For these scholars, the nature of the international system dictates that a state possess limited external interests, maintain a small military, and pursue a restrained foreign policy." Because the international system pushes states toward adopting moderate grand strategies, defensive realism must place the causes of aggression and conflict at the unit level.

Contrary to Zakaria's claims, defensive realism assumes (as does offensive realism) that at minimum all states seek to survive under anarchy. This assumption does not preclude expansive definitions of states' security requirements or states' pursuit of nonsecurity goals. Again, structural modifiers, such as the offense-defense balance in military technology and states' geographic proximity to one another, influence the severity of the security dilemma. As noted above, under certain circumstances, defensive neorealism expects states to pursue expansionist strategies as a means to achieve security.

CRITICISM 4: THE SECURITY DILEMMA AND POWER MAXIMIZATION

Several offensive realists take power-maximizing behavior to be the logical consequence of anarchy and the security dilemma. The international system provides strong incentives for the pursuit of expansionist foreign policies because only the strongest states stand the best chance of survival. States seek opportunities to weaken potential adversaries and improve their relative power positions. Expansion is often the best way to accumulate more power at the expense of rivals.Weak states are unlikely to pursue expansionist strategies because the risks of doing so are high. Stronger states rationally adapt to the international environment and quickly learn to expand when and where the costs and risks seem manageable. Eric Labs observes, "Successful expanders learn from past mistakes and they try to go about expanding in a manner that draws the least attention of the other great powers. ... When Russia was defeated in the Crimean War, the lesson it took away was not that it should not try to expand, but that it should try to expand elsewhere."

There are two responses to this argument–one deductive and the other empirical. Glaser identifies three deductive reasons why power maximization is self-defeating. First, a state that increases its relative power might nevertheless decrease its own security. By making an adversary less secure, a state might inadvertently increase the value an adversary places on expansion. Second, relative power maximization increases the probability of losing an arms race. "Even a country that would prefer to win an arms race—that is, that would prefer superiority to parity-might choose cooperation over arms racing to avoid the risk of losing the race." Third, by failing to distinguish between offensive and defensive potential, the claim that states maximize relative power ignores the fact that doing so may not maximize the military capabilities that a state needs for deterrence or defense.

A related theoretical critique concerns the prevalence of hegemony—a situation where one great power enjoys a preponderance of the material capabilities in the international system. Relative power maximization poses no problem for hegemonic, long cycle, and power transition theories, which see world politics as a succession of hegemonic systems. Because states seek to maximize relative power and the concentration of power promotes international stability, hegemonic periods will be far more common and of longer duration than balance-of-power theorists believe. The power maximization argument does present a theoretical problem for other offensive realists, such as Mearsheimer and Labs, who argue that states generally balance against increases in power.

One way out of this problem is to make a distinction between manual and automatic expansion analogous to Inis Claude's distinction between manual and automatic balancing. Manual expansion occurs when a state makes a conscious bid to maximize relative power with the aim of becoming the dominant state in the international system. Automatic expansion, on the other hand, occurs when states make localized, incremental efforts to expand with the aim of exploiting international opportunities. If anarchy provides incentives for relative power maximization but balancing is the norm, then it only makes sense for states to engage in automatic expansion.

CRITICISM 5: DEFENSIVE REALISM AND MATERIAL POWER

In their critique of contemporary realism, Jeffrey Legro and Andrew Moravcsik fault defensive realism's attention to elite beliefs and perceptions of material power. Legro and Moravcsik contend that realism is a rationalist research program. The explicit inclusion of elite perceptions and belief systems effectively removes defensive realism from the realist paradigm altogether. They argue,"If the perceptions and beliefs about effective means-ends calculations, given adequate information, consistently fail to correspond to material power relationships, then power is at best one of a number of important factors and perhaps a secondary one. The parsimony and coherence of realist theory is eroded. When recent realists theorize this relationship more explicitly, moreover, they are forced to borrow propositions more fully elaborated in existing epistemic theories, which theorize the influence of societal beliefs that structure means-ends calculations and affect perceptions of the environment."

Legro and Moravcşik present a flawed critique in three respects. First, most defensive realişts do not claim that states' foreign policies or international outcomes consistently fail to correspond to material power relationships. On the contrary, all variants of contemporary realism assume that the international system is mostly, although not exclusively, responsible for states' external behavior. Material capabilities shape the broad parameters of what can and will happen in the international arena.

Over the long run, international outcomes correspond to the relative distribution of material capabilities. In the short run, however, defensive neoclassical realism expects an indirect and problematic causal path between material capabilities (both the gross distribution of power and structural modifiers) and a state's foreign policy. As Aaron Friedberg notes: "Structural considerations provide a useful point from which to begin the analysis of international politics rather than a place at which to end it. Even if one acknowledges that structures exist and are important, there is still the question of how statesmen grasp their counters from the inside, so to speak." It is sensible, therefore, that neoclassical realist theories specify the mechanism through which policy inputs translate into policy outputs-namely, the various diplomatic, military, foreign economic, and national security strategies states actually pursue.

Material capabilities can influence states' external behavior only through the medium of central decision makers' perceptions, calculations, and estimates. Purely quantitative indicators of capabilities simply cannot capture decisionmakers' assessments. Moreover, as William Wohlforth notes, "All policies are future-oriented. All decisions are bets on the future. A decision to reform, retrench, or go to war reflects expectations about future trends and assessments of the likely effect of today's policies on tomorrow's distribution of relative power."

Second, Legro and Moravcsik overstate the extent to which one can classify realism as a "rationalist" program. Classical realism, neorealism, and neoclassical realism have an ambiguous and tenuous relationship to rational models of social behavior. Twentieth-century classical realists held ambivalent (and often inconsistent) views on rationality. Consider the writings of Hans Morgenthau. His six principles of political realism adopt rational reconstruction from the viewpoint of political leaders as a way of comprehending foreign policy. He defines political power as a "psychological relation" between weak and strong actors flowing from "the expectation of benefits, the fear of disadvantages, [and] the respect or love for men or institutions." In a previous book, Morgenthau criticizes liberalism as a "repudiation of politics" and declares, "Our civilization assumes that the social world is susceptible to rational control conceived after the model of the natural sciences, while the experiences, domestic and international, of the age contradict this assumption." Similarly, John Herz notes an underlying irrationality in human beings' simultaneous interdependence and "necessity for distrusting and possibly destroying" one another.10s

Likewise, the microfoundations of neorealism are unclear. Consider Robert Keohane's widely accepted claim that rationality is a hard-core assumption for both classical realism and neorealism.110 Waltz, however, explicitly states that his neorealist balance-of-power theory "requires no assumption of rationality," and that over time, the international system conditions state behavior through the processes of socialization and competition. In response to Keohane's assertion, Waltz places "the notion of selection' in a position of central importance," noting that "one cannot expect of political leaders the nicely calculated decisions that the word 'rationality' suggests."

Third, Legro and Moravcsik downplay the methodological reasons for examining elite decision making. For any foreign policy theory to explain state behavior, it must specify the mechanism through which the independent variable translates into policies.  Wohlforth's response to critics of realism's ability to explain the Soviet Union's peaceful decline is equally applicable here: "Critics of realism contrast a simplistic view of the relationship between [relative] decline and policy change against a nuanced and complex view of the relationship between their favored explanatory variable and policy change." By ruling an examination of actual decisionmaking outside the realist rubric, Legro and Moravcsik effectively privilege nonrealist theories.

CRITICISM 6: DEFENSIVE REALISM AND UNITARY RATIONAL ACTORS

Legro and Moravcsik argue that the inclusion of domestic variables in defensive neoclassical realism violates a core tenet of realism—the assumption of unitary, rational actors existing in an anarchic environment. By rejecting the notion that all states have fixed and uniformly conflictual preferences, defensive neoclassical realists must rely on unit-level factors to explain variation in states' motivations. Legro and Moravcsik write, "Such explanations inevitably import consideration of exogenous variation in the societal and cultural sources of state preferences, thereby sacrificing both the coherence of realism and approaching midrange theories of interstate conflict based on liberal assumptions."  To support this point, they cite Arnold Wolfers's admonition against ad hoc extensions of realism: "One consequence of distinctions such as these [between status quo and revisionist states) is worth mentioning. They rob [realist] theory of the determinate and predictive character that seems to give the pure power hypothesis its peculiar value. It can no longer be said of the actual world, for example, that a power vacuum cannot exist for any length of time."

Legro and Moravcsik base their sweeping critique of contemporary realism on Imre Lakatos's methodology of scientific research programs (MSRP), although they evade specifying their philosophy of science. They write, "When theoretical explanation of empirical findings within a paradigm consistently relies on auxiliary assumptions unconnected to core assumptions to predict novel facts or clear up anomalies, we learn little about the veracity of those assumptions. When it relies on auxiliary assumptions contradictory to underlying core assumptions, our confidence in those core assumptions should weaken."

Debates over whether Lakatos's MSRP is even an appropriate standard against which to judge international relations and foreign policy theories, Legro and Moravcsik fail to address the more important question: Why should one care? What are the empirical consequences of not adhering to Lakatos's standard for judging scientific research programs? Legro and Moravcsik fault the inclusion of domestic variables in Jack Snyder's logrolling theory of imperialism and Joseph Grieco's application of defensive neorealism to the study of international trade disputes, but they do not show how such theoretical "degeneration" hinders our understanding of real-world phenomena.

Conclusions

Offensive realism predicts frequent internationally driven expansion and holds that all states strive to maximize relative power. Anarchy compels states to seek opportunities to weaken potential adversaries and improve their relative power positions. Defensive realism presents a slightly more optimistic view of international politics. States strive to maximize relative security, not relative power. The international system itself provides incentives for expansion and aggressive strategies only under very limited conditions. States often can achieve security by pursuing moderate foreign policies.

This article has sought to advance the intrarealist debate in three ways. First, it drew a distinction between neorealism and neoclassical realism, both of which have offensive and defensive variants. Dividing realism along these lines allows us to distinguish between different assumptions about the implications of anarchy and the empirical range of particular theories. Second, the article examined four auxiliary assumptions underlying defensive neorealism and defensive neoclassical realism: (1) The security dilemma is an intractable feature of anarchy; (2) structural modifiers influence the severity of the security dilemma in particular regions or between particular states; (3) material power drives states' foreign policies through the medium of leaders' calculations and perceptions; and (4) domestic politics limits the efficiency of states' responses to systemic imperatives. Third, the article responded to several criticisms raised by offensive realists and nonrealists.

As noted at the outset, the intrarealist debate has implications for the conduct of foreign policy. Since 1991, the United States has enjoyed preponderance in all underlying components of power: military capabilities, technology, geography, population, and economic resources. It currently faces no single great power competitor or hostile great power coalition. Unipolarity may well last for several decades. Over the long run, however, the relative distribution of power will change, and new great power competitors will arise.

Defensive realism highlights the long-term perils for the United States in pursuing short-term, unilateral, and potentially provocative policies such as the development of a national missile defense (NMD) system and the pursuit of "humanitarian" military interventions and "cruise missile diplomacy" in other great powers' spheres of influence. At first glance, the costs and risks associated with these and other policies appear minimal. Leaving aside questions of technical feasibility or even the existence of a ballistic missile threat from North Korea, Iran, or Iraq, only the United States has the resources to develop an NMD. Only U.S. leadership and military capabilities (exercised through NATO) could bring an end to war and ethnic cleansing in BosniaHerzegovina and Kosovo. Last year, the United States waged an air war in Serbia for seventy-eight days without suffering a single casualty.

Although the security rationale behind these policies may seem perfectly obvious to officials in Washington, other great powers will worry about a future malign turn in U.S. intentions. The security dilemma continues to operate under unipolarity: Steps the United States takes to enhance its security will decrease the security of other states. The development and possible deployment of NMD may shift the offense-defense balance (or at least leaders' perceptions of the balance), thus negating the pacifying effects of mutual assured destruction. This in turn will force Russia to place even greater reliance on its strategic nuclear weapons, thus jeopardizing the prospects for a START III treaty. China will likely respond to NMD development by increasing its number of intercontinental ballistic missiles, which might spark a nuclear arms race with India. The U.S. victory in the Kosovo conflict exposed the inadequacies of the Western European states' military capabilities. The conduct of the war, and the diplomatic talks that proceeded it, exacerbated tensions between the United States and its NATO allies and between the West and Russia. Another round of NATO expansion would only increase Russia's sense of vulnerability and encirclement. Although China, Russia, Japan, and the European Union will not be able to counterbalance the lone superpower in the near future, the United States can ill afford to alienate them in the end. Defensive realism suggests that the next administration can best ensure U.S. security in the twenty-first century through a strategy of selective engagement.

Beyond its policy relevance, the current intrarealist debate suggests at least three avenues for future research. First, both offensive neorealists and defensive neorealists should be more explicit about the assumptions that underlie their theories. Second, both offensive realism and defensive realism should devote more attention to the motivations for expansionist behavior. Defensive realists note that states will sometimes engage in security-driven expansion, but that over the long run, self-aggrandizement will prove self-defeating. Offensive neorealists pay considerable attention to expansionist states and see them as the prime movers in international politics. The motivation for expansionist behavior-greed or security-remains underdeveloped in both camps. Third, both the offensive and defensive variants of neoclassical realism hold that perceptions and misperceptions among top leaders may inhibit a state's ability to respond to changes in relative capabilities. The link between objective changes in relative power and leaders' perceptions of relative power is underdeveloped. Future offensive and defensive neoclassical realist theories should be more explicit in incorporating insights from cognitive and social psychology.  The debate between the two branches of contemporary realism over the implications of anarchy need not lead to a permanent bifurcation. By combining defensive realism's assumptions about structural modifiers with offensive realism's assumptions about expansionist states, scholars might develop more powerful international relations and foreign policy theories.

Source:Semantic scholar