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Bipolarism and Its End, From the Cold War to the Post-Cold War World

Summary and Keywords

Bipolarity was viewed both as an empirical condition and as a central explanatory concept, albeit contested, during the Cold War (1945–1989), when two superpowers dominated the international system. The United States and the Union of Soviet Socialist Republics (USSR) confronted each other as military and ideological rivals heading competing alliance systems—the North Atlantic Treaty Organization (NATO), founded in 1949, and the Warsaw Pact established in 1955. Nuclear weaponry added a new wrinkle to the global superpower competition, particularly after the Soviet Union broke the American nuclear monopoly in 1949. A rich literature around these themes emerged as scholars sought to grapple with the explanatory dynamics propelling state behavior under the systemic constraints of bipolarity and the technological challenges presaged by the nuclear age. Such an academic focus meant that the study of international politics, particularly in the United States, was largely refracted through the prism of U.S.-Soviet competition and centered on the nature and implications of polarity, power, alliances, and nuclear deterrence. When the Soviet Union imploded, bipolarity in the sense of two predominant powers ended, as did the division of the world into two opposing blocs. In the post-Cold War period, scholars turned their attention to investigating questions regarding the impact on the nature of system structure and the international order of the collapse of one of the poles.

Accordingly, during the Cold War, scholars debated the conceptual and empirical understandings of bipolarity as well as its implications and the causal factors on which the expectation of bipolar stability was based. In the post-Cold War period, scholars reflected over whether the end of ideological (capitalism/democracy vs. communism/single party authoritarianism) conflict presaged the end of history or inaugurated a clash of civilizations, with some questioning the salience of the concept of polarity and the viability of the state system in the face of rising subnational and transnational pressures.

Keywords: bipolarity, unipolarity, non-polarity, hegemony, Cold War, post-Cold War era, Marxism, capitalism, balance of power, correlation of forces

Introduction

Bipolarity was viewed both as an empirical condition and as a central explanatory concept, albeit contested, during the Cold War (1945–1989), when two superpowers dominated the international system. The United States and the Union of Soviet Socialist Republics (USSR) confronted each other as military and ideological rivals heading competing alliance systems—the North Atlantic Treaty Organization (NATO), founded in 1949, and the Warsaw Pact, established in 1955. Nuclear weaponry added a new wrinkle to the global superpower competition, particularly after the Soviet Union broke the American nuclear monopoly in 1949. A rich literature around these themes emerged as scholars sought to grapple with the explanatory dynamics propelling state behavior under the systemic constraints of bipolarity and the technological challenges presaged by the nuclear age. Such an academic focus meant that the study of international politics, particularly in the United States, was largely refracted through the prism of U.S.-Soviet competition and centered on the nature and implications of polarity, power, alliances, and nuclear deterrence.

William T. R. Fox is credited with introducing the neologism superpowers (Fox, 1944). For Fox, who applied the term to the United States, the Union of Soviet Socialist Republics (USSR), and Britain, the primary distinguishing characteristic of these states in the post-World War II period, unlike the erstwhile regional great powers of Europe and Asia, was “great power plus great mobility of power” (Fox, 1980, p. 417), suggesting not just predominance in measures of hard (military and economic) power, but also the ability to project this power globally. After 1945, as the Cold War unfolded with two protagonists, the superpower appellation came to be applied solely to the United States and the Soviet Union (Morgenthau, 1972). In a later work, Fox himself limited the term to two powers and further noted, in reference to advancements in Soviet nuclear weaponry, that after 1955 “talk of massive retaliation or of rolling the Russians back out of Eastern Europe” had abated and the “era of declaratory bipolarity had given way to real bipolarity” (1980, pp. 428–429).

As the concepts of polarity and power are inextricably linked because the number of poles is determined by how much power is concentrated in the top states in the interstate system, the protean nature of power fueled vigorous intellectual sparring within and among theoretical traditions over the meaning and nature of bipolarity. The first section of this article addresses the state of scholarship on the following questions: What did bipolarity entail in an empirical sense? How exactly where the number of powerful states at the apex of the system to be determined? What measures of power were pertinent? These lines of inquiry also bled into the implications of bipolarity: On what causal factors was the expectation of bipolar stability based? If power meant influence, how was superpower influence to be measured? If superpower preferences were often overridden, did this suggest that the system was not bipolar? The first part of this essay will engage with the questions noted above. The end of Cold War bipolarity with the implosion of the Soviet Union inaugurated much scholarly hand-wringing over how best to characterize the international system and, in the face of rising global challenges, over the salience of the interstate order. The second part of the article explores questions that animated scholars investigating the post-Cold War period: Did the end of ideological (capitalism/democracy vs. communism/single party authoritarianism) conflict presage the end of history or a clash of civilizations? Would the state system continue to remain viable in the face of rising subnational and transnational pressures, reducing the salience of the concept of polarity? Was the post-Cold War interstate system unipolar, multipolar, uni-multipolar, non-polar? Or, was another period of bipolarity being inaugurated with the rise of China, as a peer competitor, and if so, what might this return to bipolarity entail?

The Cold War and Bipolarity

Emerging as a ubiquitous term with the start of a cold war between the United States and the Soviet Union after World War II, the term bipolarity came in the cross-hairs of scholarly debate. A set of prior and important questions, however, arose with respect to the manner in which superpower hostility unfolded. What was the Cold War, what rendered it cold and why was it cold? The responses to these questions held a clue as to the salience and significance of the concept of bipolarity. The easy answer, of course, was that the Cold War was cold because of the absence of its opposite—a hot war; but more pertinent was the question of why the postwar anti-German alliance, which after 1941 included the Soviet Union, fell apart even as the war began winding down and why, if that were the case, the fighting (hot) phase of the war ended with German defeat. One reason was that the roots of the US-Soviet conflict predated World War II as the antipathetic ideologies of communism and capitalism and the very different principles and forms of government that the state votaries of each ideology embraced had created a reservoir of distrust that dated to the success of the 1917 communist revolution in the USSR. This certainly helped explain why the U.S.-Soviet rupture in the pragmatic interest-based anti-German alliance occurred with the imminent defeat of Germany and why the German-occupied areas of the European continent, liberated respectively by Soviet and British-U.S. allied forces, soon metamorphosed into two rival zones led by the United States and the Soviet Union.

The clues for why this war remained cold could be found in the circumstances of the postwar Soviet Union. In the immediate aftermath of German defeat, an economically devastated and militarily spent USSR was in no position to use force to achieve control over the western half of Europe against an opponent (the United States) whose continental territory had emerged unscathed from the war that had raged relentlessly on the European continent. As the ideological battle lines hardened with the gradual imposition of Soviet-style governments in Eastern Europe and in Soviet-controlled divided Germany, a “cold” ideological war began in earnest. Bipolarity, then, conceptualized in terms of two predominant powers facing off against each other across what Churchill memorably referred to as an iron curtain, had a historical referent in Europe as none of the erstwhile European powers, including Britain, possessed the military and economic wherewithal to challenge the Soviet Union. The Soviet threat to Western Europe was at that time primarily ideological rather than military or economic.

In the waning months of the war, with the bombing of Hiroshima and Nagasaki, the United States demonstrated with horrifying clarity the devastating power of a technologically new breakthrough in military technology—the atom bomb. The U.S. monopoly on the nuclear bomb was short-lived, and when the USSR joined the United States in 1949, as a nuclear power, scholars grappled with the question of how this new technology affected superpower rivalry. On the heels of this discontinuous challenge posed by a new military technology came the decolonization process, which on the one hand clearly signaled the erosion of power of the erstwhile European great powers and on the other hand opened up to superpower competition a wide swath of the world with newly-independent and uncommitted states. Scholars soon found ways to connect these two developments, arguing that the superpowers, in pursuit of their attempts at expanding influence globally, avoided direct military intervention in these countries to avoid the risk of escalation to a nuclear war. The literature on nuclear deterrence, especially after both superpowers had achieved credible second-strike capabilities, thus offered further insights into why the Cold War remained cold and suggested reasons for the rise of proxy wars in regions of the world where state allegiances to the United States or the Soviet Union were undeclared. In the area of scholarship, debate ensued over how best to understand the bipolarity-nuclear weapons connection.

Bipolarity as an Explanatory Concept

These intersecting historical threads gave rise to a set of nested questions. Realist scholars were in the forefront of intellectual attempts to decode the postwar world. Was bipolarity characterized by the presence of two superpowers or two opposing blocs? Classical and neorealist academics conceptualized bipolarity in terms of an international system with two predominant powers. The emergence of two alliance systems was seen as derivative of the bipolar distribution of power. In his seminal 1948 work, Politics Among Nations, Hans Morgenthau, a modern classical realist who had sought to systematize the study of international politics, posited that national interest defined in terms of power offered scholars an objective category for analysis (Morgenthau, 2006, p. 5). In the post-World War II era, Morgenthau observed, “the power of the United States and of the Soviet Union in comparison with the power of their actual or prospective allies” had become “so overwhelming” that through their “own preponderant weight” alone they determined “the balance of power between them” unaffected in the short term by “changes in the alignments of one or the other of their allies” (pp. 349–350). Bipolarity, then, was viewed as a function of preponderance measured in terms of military might that was immediately deployable; economic and political strength, representing a mix of tangible and intangible potential power; and stable factors, such as geographical location, size of territory, and access to natural resources (pp. 122–162). But while the United States and the Soviet Union enjoyed “overwhelming power vis-à-vis their allies,” this power was not “without limits” and therefore required the superpowers to “adapt their policies to the wishes of their allies,” in order to enjoy “maximum support” (p. 350). Due to the insurmountable gap in power, however, allies of each superpower, arrayed in two opposing blocs, could not defect and independently form third force alliances powerful enough to sway the bipolar balance. Additionally, even the “prospective moves of the uncommitted nations” provided for “flexibility” only in the long-term balance of power. In the short-term, with the end of colonialism and the rise of independent states in Asia and Africa, the presence of nonaligned states created a vast battleground for the play of superpower competition (Morgenthau, 2006, p. 351).

Morgenthau placed Cold War bipolarity not just within a structural context wherein two great powers dominated the international system, but also within an environment of norm breakdown following the rise of nationalism after the end of World War I which, in his view, inaugurated a new era of superpower competition. The post-World I era was transformational inasmuch as states no longer worked “within a framework of shared beliefs and common values” that imposed “effective limitations upon the ends and means of their struggle for power.” Instead, driven by “nationalistic universalism,” states opposed one another as “standard-bearers of ethical systems, each of them of national origin and each of them claiming and aspiring to provide a supranational framework of moral standards that all other nations ought to accept and within which their foreign policies ought to operate” (Morgenthau, 2006, pp. 262, 338–339). Such a worldview, he felt, drew the United States into the Vietnam War. A fierce opponent of that war, Morgenthau distinguished between the military threat that the United States and its allies faced in Europe in contrast to the political threat confronted in Asia against which military containment, he argued, was both “irrelevant” and counterproductive” (Morgenthau, 1965, p. 25).

Kenneth Waltz echoed many of Morgenthau’s arguments but also departed from key elements of classical realist thinking. In his quest to develop a parsimonious theory of international politics, Waltz stripped away the normative aspects of the classical realist framework and ontologically prioritized system structure over state agency. In two works, Waltz set out the core assumptions of what came to be termed neorealism. In Man, the State, and War, Waltz (1959) introduced three levels of analysis (images) to explain the causes of interstate war with explanatory variables offered at the individual (first image), intra-state (second image), and interstate or systemic (third image) levels. He posited that, while explanations lodged at all levels were necessary and no single level by itself was sufficient in explaining the causes of war, the third image was indispensable. Waltz developed this idea further in his groundbreaking book, Theory of International Politics (1979). There, he presented a neo-realist argument for the primacy of structural variables in explaining international political outcomes. Structural anarchy elevated the significance of power differentials among like units (states). Hence the balance (or distribution) of power was the primary explanatory variable in international politics. States could “balance” internally (increasing military might) or externally (forming alliances). While careful not to impute automaticity to systemic pressures, and to insist that he was offering a theory of international politics rather than of foreign policy, Waltz averred that structure constrained the actions (external choices) of states (Waltz, 1996). Hence, leaders interested in state survival (an interest imputed to all states by assumption) who neglected these constraints, jeopardized the autonomy and/or existence of their states. Security was a prime consideration for all states and concern with the security dilemma (a situation wherein actions undertaken by one state to increase security induced perceptions of insecurity in a rival state leading to an arms race cycle) led states to accrue arms sufficient to ensure survival. This interpretation earned Waltz the moniker of a defensive neorealist in contrast to the argument advanced by John Mearsheimer (2001), an offensive neorealist, who argued that the pursuit of security propelled states to pursue hegemonic aims.

Waltz, as Morgenthau before him, viewed bipolarity in terms of the unequaled power of the United States and the Soviet Union. Explaining the link between polarity and power, Waltz noted that the power of the United States and the Soviet Union was “predominant but not absolute” and that their global influence and control could not be equated with domination. To say that the world was bipolar, he averred, did not suggest that either power could “exert a positive control everywhere in the world.” Each, however, had “global interests” that could be addressed unaided if necessary (1964, p. 888). Both, in other words, had global power projection capacities. The measure of predominance was arrived at through a calculation primarily of economic and military strength gleaned through such measures as gross national product, military spending, and military capabilities (pp. 892–898). As a “descriptive term,” Waltz asserted, bipolarity was apt as long as a “great gap” persisted “between the power of the two leading countries and the power of the next most considerable states” (p. 892). On the question of whether bipolarity was defined by the existence of two preponderant powers or two rival blocs, Waltz explained that while a bipolar world may be defined in terms of “two states or two blocs” that overshadow all others (1964, p. 887), it was important to “distinguish sharply” between “a bipolarity of blocs from a bipolarity of countries” (p. 900). Due to the predominant power of the alliance leaders in bipolarity, issues of alliance management and defection, Waltz argued, could be handled effectively by each superpower while simultaneously remaining attentive to the objectives and capabilities of the rival bloc (pp. 899–900).

While Morgenthau and Waltz defined bipolarity in terms of two predominant powers, neither offered a clear guide as to how exactly to operationalize such power or how significant the power gap had to be that separated first tier superpowers from second-tier powers. Debate swirled around this question. Dean and Vasquez (1976) and Wagner (1996) drew attention to this failure of specification that prevented empirical testing of whether the system was or was not bipolar. Choosing an operationalization of power as a measure of how capabilities translated into influence and defining preponderance as a situation in which “on every issue (or at least all ‘major’ issues) the same two nations have more power than any other actor or combination of actors” (Dean & Vasquez, 1976, p. 13), and after conducting a preliminary analysis based on this very restrictive operationalization, Dean and Vasquez concluded that “a bipolar system in the sense of two nations having preponderance of power simply never existed in the post-World War II period” (p. 14). Wagner leveled the same criticism centered on what two-power bipolarity entailed but asked instead “how much more powerful these powers [had] to be?” He also added that one could not, based on Waltz’s criteria, find clear indicators to gauge when bipolarity ended: “How small did the structure of the Soviet economy have to become before the structure of the international system could be said to have changed?” (Wagner, 1996, pp. 85, 88). Wagner claimed that, based on his analysis, bipolarity as two powers had no referents to any historical international system (p. 89).

Just a year before Wagner penned his critique, Volgy and Imwalle (1995) had sought to test hypotheses based on bipolarity and hegemony. Distinguishing among the concepts of bipolarization (respective alliances in a position of substantial mutual conflict), bipolarity (two powers controlling a dominant share of military capabilities in the system as a whole), and relative balance (each power commanding military capabilities that posed a substantial threat to the other power), the authors suggested that to consider a system bipolar, the relative balance and bipolarization could and might have fluctuated but the level of bipolarity had to meet “a certain minimum threshold” for the system to be characterized as bipolar (Volgy & Imwalle, 1995, p. 820). Based on the work of Rapkin, Thompson, Christopherson (1979), and of Thompson (1986), Volgy and Imwalle posited that bipolarity existed operationally when two states controlled at least 50% of relative military capabilities, with each of the two states controlling at least 25%, while no other state controlled as much as 25% (Volgy & Imwalle, p. 820). Using military expenditures as a measure of relative military capability and “the universe of ‘great powers’ during the period as the baseline” from which to “assess relative share of capabilities,” the authors, contrary to the conclusions of Dean/Vasquez and Wagner, contended that the data upheld “the bipolar nature” of the system even though the system was not static but dynamic with “significant fluctuations in bipolar shares of systemic capabilities relative to other actors,” as well as the extent of the relative balance between the two poles (Volgy & Imwalle, p. 822).

Much of the research and debate over questions of polarity and alliances during the Cold War suffered from an undue focus on the European theater. Even Wagner’s critique ranges in its historical referents only to Europe. Perhaps the superpower appellation applied to the United States and the Soviet Union as well as the association of bipolarity to preponderance in power would make more sense if historical developments across the entire globe were included in the analysis. Wagner’s contention that “tightness” of power after World War II with Soviet peacetime control over much of Europe helps explain all the anomalies that the bipolarity of Waltzian neorealism fails to capture is itself incomplete. First, Soviet peacetime control over Eastern Europe was the consequence of a war in which the USSR fought on the side of the allies to defeat Germany. Examining why that alliance disintegrated as the war wound down is important. Wagner’s contention sidesteps the reason for the breakdown of the anti-German alliance, which was the deep-seated distrust of communist ideology and the concern over its spread in Europe, which made the continued Soviet peacetime occupation more menacing.

Second, as Morgenthau had pointed out, nationalistic universalism manifested in missionary impulses that colored how interests were viewed both in the Soviet Union and in the United States. Moreover, with Europe locked into rival alliances a few years after the war, superpower competition soon shifted to Asia and Africa in the wake of decolonization. Here, the U.S.-led NATO alliance that included Britain and France provided easy pathways for an extension of U.S. influence in areas that were formerly British and French colonies. It was in this sense that bipolarity conceptualized as U.S. and Soviet predominance had important historical referents. British withdrawal from east of the Suez and French withdrawal from Vietnam, to offer two examples, drew in the United States as the global competition for superpower influence heated up. Global superpower rivalry also affected scholarly treatment of wars with autochthonous causes, such as the India-Pakistan wars and the Arab-Israeli wars as both the United States and the Soviet Union superimposed their interests by often supporting opposite sides. Bipolarity conceptualized as two powers (rather than two blocs) captured the phenomenon of proxy wars in Asia and Africa.

Bipolarity, Stability, and Peace

What were the implications of bipolarity? Did it operate as a causal mechanism and if so, what did it explain? On this question, both classical and neorealism offered explanations that underspecified outcomes. Waltz saw bipolarity as contributing to stability while Morgenthau saw bipolar systems as unstable. What did stability entail? Morgenthau defined stability in terms of system durability. Europe, he stated, enjoyed “two periods of stability, one starting in 1648 and the other in 1815,” during which “universal dominion by one state was prevented” and a multipolar system preserved, but only at the price of “virtually continuous” warfare (Morgenthau, 2006, p. 213). Waltz measured stability “by the peacefulness of adjustment within the international system and by the durability of the system itself” (1964, p. 881). Both Morgenthau and Waltz viewed stability as a function of levels of certainty/uncertainty in state interactions on matters of high politics (and thus the potential for miscalculation) that the number of alliances deriving from a given system of polarity generated.

Morgenthau upheld the notion of balance of power as both a motive principle of interstate politics and a guide to state policy, seeing it as a dynamic rather than solely mechanistic force and highlighting the value of diplomacy, statesmanship, and international norms either in ameliorating or in failing to redress the adversarial impact of structural elements of the international system. He argued that the “extreme flexibility of the balance of power [in multipolarity] resulting from the utter unreliability of alliances made it imperative for all players to be cautious in their moves on the chessboard of international politics, and since risks were hard to calculate, compelled them to take as small risks as possible” (Morgenthau, 2006, p. 349). The Cold War bipolar system, on the other hand, reduced both “the flexibility of the balance of power and with it, its restraining influence upon the power aspirations of the main protagonists” (Morgenthau, 2006, p. 350). The central bipolar alliances were inflexible whether alliance partners acted as “willing and effective supporters” or “balky and unreliable captives” of superpower policies. Flexibility in the balance of power came only over the long-term and depended on the “prospective moves of uncommitted states” (p. 351).

Supporting Morgenthau, Deutsch and Singer listed several reasons for the stability of multipolar systems: multipolar systems engendered shifting alliances among the poles, allowing for a multiplicity of interaction possibilities; uncertainty relating to the outcome of conflict and war induced caution not just for the poles but also for smaller states; cross-cutting cleavages among states reduced the rigidity of the conflict; and shifting alliances meant that arms races played out at a slower pace (Deutsch & Singer, 1964). Waltz, who disagreed with this position, detailed his arguments in a 1964 article on “The Stability of a Bipolar World.” In bipolar systems, there were no peripheries; both superpowers had the interest and capacity to manage their respective alliance systems; there was not as great a danger of miscalculation; and that when crises occurred, the de-escalation not only engaged the full attention of both superpowers, but their occurrence suggested that neither superpower wished to test the other in a war. In multipolar systems, Waltz argued, states enjoyed a shifting array of multiple alliance possibilities, which increased the level of uncertainty and thereby raised the risk of miscalculation. They were therefore not as stable as bipolar systems (Monteiro, 2011/2012; Waltz, 1964, pp. 882–885, 1988, pp. 620–623). Great power war was therefore more likely in multipolar than in bipolar systems.

At the theoretical level, this debate left open the question of which system—multipolar or bipolar—was more stable. Realist scholars sought to address this stability/instability conundrum by examining variables at the state-level that could explain the paradox. Offense-defense theory was one such attempt (Jervis, 1978; van Evera, 1998). Van Evera suggested that when offensive military technologies dominated, states engaged in “opportunistic expansion” because costs were not high, and conquest was “easy.” Conversely, when defensive technologies dominated, states were “less aggressive and more willing to accept the status quo (van Evera, 1998, pp. 7–8). This argument also met with its share of criticism (Glaser & Kaufmann, 1998; Lynn-Jones, 1995). At the empirical level, Dean and Vasquez drew attention to the implications for system stability and war propensity for defining bipolarity in terms of the existence of two preponderant powers or of two power blocs. They asserted that the operational criteria for testing these hypotheses empirically differed in each case, with national power salient in the first and an examination of blocs and interaction opportunities in the second. They also held that empirical referents for the second were more readily measurable than those for the first (Dean & Vasquez, 1976, pp. 11–13; Vasquez, 1993). This circumstance, they argued led to a paucity of quantitative studies delving into the causal link between system stability and war proneness of bipolarity defined in terms of the preponderant power of two states while there were ample examples of studies that examined the nexus between stability/peace and bipolarity defined as two blocs (Alexandroff et al., 1972; Haas, 1970; Singer & Small, 1968).

The debate over the implications of adopting one or other conceptualization of bipolarity for explaining whether superpower preferences lined up with international outcomes hinged then on how one defined preponderance of power and the stability and war-proneness of the system. Did preponderance mean that all outcomes had to be aligned with the preferences of one or the other superpower, particularly in their respective blocs and among their ideologically-kin states? As noted above, Morgenthau and Waltz interpreted preponderance in terms of preponderant capabilities and conceded that superpower influence was not absolute. Their argument for bipolarity as power rested on the assertion that no other actor could, through their choices and actions, displace the superpowers from their perch of preponderance or fight them on matters of primary national interest—neither superpower, for instance, would have allowed outright defection of bloc members to the alliance system of the adversary. With the debate unresolved, the explanatory value of bipolarity came into question.

Not all scholars attributed systemic stability to polar structure. A. F. K. Organski, who is credited with originating power transition theory, posited that differential rates of social, economic, and political modernization underlay shifts in the distribution of world power among states (Organski, 1958; Organski & Kugler, 1980). Power transition theorists who followed in the footsteps of Organski argued that anarchy operated as a contingent variable. Drawing on structural- and domestic-level variables, they posited that system stability was largely a function of the level of satisfaction with the international order established by the dominant state in coalition with stable and satisfied supporters rather than a function of polarity (Tammen, Kugler, & Lemke, 2011, p. 4). Rising dissatisfaction, which was gauged by the level of support among national elites for international norms and rules, would foment revisionist moves by states that had attained power parity with the dominant state, presaging conflict and war in the system. The likelihood of war was predicated on the size of the power gap between the dominant and dissatisfied rising power and the ability of the latter to mount a credible challenge. Thus, states would “act as if in anarchy when directly threatened or while waging war” but satisfied powers would “willingly coordinate efforts and cooperate” in peacetime through alliances and international organizations (Tammen et al., 2011, pp. 5, 8).

Empirical developments affected the scholarly conversation on bipolarity. The expectation of tight alliance systems largely held true until the mid-fifties to early sixties. When in the 1960s France in NATO and Yugoslavia in the Warsaw Pact respectively challenged their alliance leaders and after the Sino-Soviet split became public, debates soon arose over the structure of the international system. In the 1970s, scholars began to explore the phenomenon of strategic triangularity when the United States, in an effort to pressure the Soviet Union, played the “China card” (Dittmer, 1981). Waltz (1964, 1988) claimed that system remained essentially bipolar even with the loosening of alliance systems, while others argued that the system was trending in a multipolar direction and questioned the explanatory potential of the concept of bipolarity. Hanrieder (1965) noted that, as “variations among system types” largely connoted “variations of patterns” in interstate relations, the more the variations that were “formulated to accommodate historical reality,” the less the justification for considering “international relations in terms of systems at all” (Hanrieder, 1965, p. 301). Specifically, on the concept of bipolarity, he somewhat hyperbolically remarked, that if “a new ‘sub’-typology of bipolarity” had to be formulated “every year to keep up with the pace of history, the label of bipolarity would embrace so many variations that each one would hardly be more than an annual appraisal of international events (Hanrieder, 1965, p. 301). In light of the vagaries of the march of history, he suggested that a more fruitful analytical approach would be to view “bipolar and multibloc patterns” as ideal types and place the sturm und drang of events as “transitory phenomena” to be slotted into a “niche” readied within a futuristic model, namely a multibloc system (Hanrieder, 1965, p. 301).

Kaplan (1957) and Masters (1961) had developed analytical specifications for ideal-type models in order to systematize the study of international systems. Hanrieder’s critique shined light on the static elements in the neorealist model of bipolarity and the inability, within the confines of neorealist assumptions, to explain satisfactorily the dynamics of structural changes in polarity due to the neorealist focus on system rather than process. To differentiate analytically among variations in patterns of interstate relationships, Hanrieder offered four analytical categories of bipolarity—symmetrical, asymmetrical, hetero-symmetrical, and hetero-asymmetrical. Symmetrical bipolarity implied an “approximate equilibrium between the two poles” and a “position of a duopoly or preponderance within the system,” and captured interaction patterns “either with reference to a specific functional area or with reference to the entire functional aggregate of the system. In asymmetrical bipolarity, the two poles remained “predominant in a particular issue area at the expense of other system actors,” but one pole enjoyed “a position of predominance over the other.” Hetero-symmetrical patterns occurred when a functional area was not “preempted by the two poles” and influence over patterns of interaction had to be “shared with third or fourth forces” but the two poles were “roughly symmetrical.” Hetero-asymmetrical captured situations in which “significant third ‘hetero’ forces . . . upset the equilibrium between the two poles” (Hanrieder, 1965, pp. 303–304, emphasis in original). These, he hoped, would allow scholars to analyze the international developments of the 1960s more productively.

Writing in 1977, Snyder and Diesing drew on a multi-pronged approach in engaging with the concepts of polarity, power, alliances, deterrence, cooperation, war, and peace. Using sixteen international crises occurring between the late 19th century and the mid-1970s as their case studies, the authors sought to apply three theoretical approaches—systems, bargaining, and decision-making in order to theorize more generally about “the pervasive expectation of potential war” among states in an anarchic international system (Snyder & Diesing, 1977, pp. 3–4). Analytically disaggregating four interrelated variables—structure (based on the distribution of military power among major states), interstate patterns of relations, major state interactions, and the internal (or domestic) characteristics of states (national styles, the nature of the decision-making process, and the relative value of individuals and agencies participating in decision making)—the authors attempted to uncover the causal links among them (Snyder & Diesing, 1977, pp. 471–472, 479). Operationalizing interactions as behavioral processes and relations as mutually held attitudes and beliefs that affected patterns of alliance and interdependence (with the latter limited to the political-strategic realm alone), the authors deduced that system structure affected relational patterns differentially. Alliances were stable in bipolar systems, especially in the central arena of conflict; but, in subsystems, while structure continued to affect alignments, it did so indirectly, “due to the tendency of the superpowers to support opposite sides in local conflicts” (p. 474). Variance in alliance patterns were greater in multipolar systems. Patterns of interaction (viewed in terms of bargaining stances) in any given polar structure were seen as outcomes of prevailing interstate relations with “degree and asymmetry of interdependence” determining relative bargaining power (p. 477). The complex dynamics among structure, relations, interactions and state characteristics, they argued, could not be reduced to structure alone.

These scholarly exchanges over the explanatory value of system level variables centered on a fundamental question: whether very general predictions regarding the effect of systemic constraints on state behavior advanced our understanding of international politics or whether theory should account for variations in patterns of state interaction when system-level variables underdetermined outcomes. Elman, for instance, asked if a theory of international politics could also encompass a theory of foreign policy and answered in the positive, mounting a spirited case for why “the neorealist horse could run the foreign policy course” offering as a heuristic device a diagrammatic portrayal of the kinds of foreign policy options that could be teased out based on the propositions contained in the neorealist research of a range of scholars (Elman, 1996, pp. 48–49).

Bipolarity and Nuclear Weapons

Another area that elicited debate was how the development of nuclear technology affected bipolarity (Brodie, 1946, 1959; Herz, 1959). The literature on nuclear deterrence during the Cold War focused on the two superpowers with the clearest ability to annihilate each other. The Soviet launch of Sputnik in 1957, with the aid of an intercontinental ballistic missile, unmistakably demonstrated its capability to strike the continental United States. Writing at a time when the U.S. nuclear posture was one of massive retaliation and a year after Sputnik, Wohlstetter cautioned against complacence, warning that deterrence was not automatic and that it would be “much harder to achieve” in the next decade. He discussed several “hurdles” that made for a delicate balance of terror (Wohlstetter, 1958). Burns (1957) argued that advances in nuclear weaponry, especially the development of the hydrogen bomb, had rendered alliances inoperable as balancing mechanisms and that states with economic and technological capabilities to counteract technological breakthroughs by rival states would become “global-deterrent” powers—a status attained only by the superpowers, which would therefore have to pursue a strategy of deterrence. By the mid-to-late 1960s, once the United States and the Soviet Union attained nuclear parity (in terms of credible second-strike capabilities on both sides), an overall asymmetry of power (either military or economic) between the superpowers would have been unlikely to undermine the situation of mutual deterrence that existed between them. Such a situation also allowed superpower competition to be played out in the form of proxy wars in the post-colonial world.

On the specific matter of the relationship between bipolarity and nuclear weapons, Morgenthau argued that the unprecedented power of the superpowers could not be attributed solely to nuclear weapons because while they were nuclear powers of the “first rank,” this position played a “decisive role” only in their mutual relations “in the form of mutual deterrence” but played “hardly any role in their relations with the other nations” (Morgenthau, 1972, p. 131). Waltz, along with Mearsheimer, argued that the stability of bipolarity operated independently of nuclear weapons (Mearsheimer, 1990, p. 7; Waltz, 1988, p. 625). Waltz challenged the idea that superpower caution in crises and the resulting bipolar stability was attributable to the existence of nuclear weapons and asserted that “nuclear capabilities merely reinforce[d] a condition that would [have] exist[ed] in their absence” because even without nuclear technology, the United States and the Soviet Union had the “ability to develop weapons of considerable destructive power.” Nuclear weapons, he concluded, “[b]y making the two strongest states still more powerful and the emergence of third powers more difficult, . . . helped consolidate a condition of bipolarity” (1964, pp. 884–885, 907). On the question of war, however, Waltz conceded that nuclear technology, which was a change at the unit-level, had a structural effect. Nuclear weapons had “banished war from the center of international politics” (Waltz, 1981, pp. 626–627).

Power transition theorists, like Lemke, raised doubts about the pacifying role of nuclear weapons in situations of extended deterrence and in crises between nuclear and non-nuclear states when the former chose not to impose their preferences on the latter (Lemke, 1997, p. 26; Tammen et al., 2011, p. 20). Rather than using bipolarity or nuclear weapons as explanatory variables for the Cold War “long peace,” power transition theorists pointed to the lack of overall power parity or the asymmetric bipolarity between the United States and the Soviet Union (Lemke, 1997, p. 27).

Bipolarity and Hegemony

While the argument of bipolarity as reflecting a system of two superpowers held wide currency in intellectual circles, several scholars investigated international politics from a different perspective—one that highlighted the salience of power asymmetries between top powers. Although the United States and the Soviet Union were both predominant military powers, the former was significantly stronger economically and technologically. Moreover, as historian Melvyn Leffler has documented, even in the early years of the Cold War, the United States harbored a hegemonic agenda. Leffler outlined the boldness of the globe-spanning American conception of national security that emerged between 1945 and 1948 as encompassing “a strategic sphere of influence within the Western Hemisphere, domination of the Atlantic and Pacific oceans, an extensive system of outlying bases to enlarge the strategic frontier and project American power, an even more extensive system of transit rights to facilitate the conversion of commercial air bases to military use, access to the resources and markets of most of Eurasia, denial of those resources to a prospective enemy, and the maintenance of nuclear superiority” (Leffler, 1984, p. 379). Leffler argued that American officials “grudgingly” acquiesced to a Soviet sphere in Eastern Europe and refrained from direct intervention in China, but challenges to American preferences outside those regions led to resolute push back as evidenced by “the Truman Doctrine, Marshall Plan, military assistance, Atlantic alliance, and German and Japanese rehabilitation” (Leffler, 1984, p. 379). The Chinese communist revolution and Soviet detonation of the atom bomb in 1949 and the North Korean attack on South Korea in 1950 elicited firm responses in the form of “military assistance to southeast Asia, a decision to build the hydrogen bomb, direct military intervention in Korea, a commitment to station troops permanently in Europe, expansion of the American alliance system, and a massive rearmament program in the United States” (Leffler, 1984, p. 379).

The hegemonic perspective was prominent in literature that sought to capture the dynamism of international politics and viewed world order as a function of hegemonic leadership exercised by the most powerful state. Under a hegemony, “one central actor [held] a unique combination of military and economic capabilities” and was “willing to lead in fashioning a world order.” Bipolarity and hegemony could coexist when “a militarily strong contender” arose and challenged the hegemon’s leadership” (Volgy & Imwalle, 1995, pp. 823–824, emphasis in original). Gilpin’s hegemonic transition theory (1981) and Thompson (1986) and Modelski’s (1978, 1987) long cycle theory of the rise and decline of global leadership held that hegemonies were stabilizing and promoted peace.

Gilpin argued that “uneven growth of power among states” was the “driving force of international relations” and developed the theory of hegemonic war to explain this dynamic (Gilpin, 1988, p. 591). In War and Change (Gilpin, 1981), he argued that change was a constant feature of international politics with the recurring struggle of states for wealth and power. A state would attempt to change the international system through territorial, political, and economic expansion as long as the expected benefits exceeded the costs. A system was in a state of equilibrium when the reigning hegemon provided order and stability in the system and powerful states were satisfied with the economic, territorial, and political status quo. Hegemonic decline undermined order. However, no hegemonic system could remain in equilibrium indefinitely because domestic and international developments in the form of changing interests and differential growth of power generated disequilibrium and altered the cost of changing the system. The decline of a hegemony occurred due to diminishing returns over time from empire, a rise in consumption with a simultaneous fall in investment, and a process of technology diffusion. This dynamic created cycles of hegemonic rise and decline. Gilpin suggested that while a resolution of a crisis of equilibrium in the system could occur through peaceful adjustment, the principal mechanism of change was hegemonic war.

Modelski and Thompson’s long cycle theory (1989) examined the recurrent rise and decline of a succession of world powers since the 16th century: Portugal, the Dutch Republic, Britain, and the United States. The rise and decline of world powers, punctuated by global wars, occurred in synchrony with the rise and decline of leading industrial and commercial sectors in the world economy. Thompson noted that “[t]he principal winner of the global war and the system’s lead economy [was] also the global system’s leading sea power (Thompson, 2006, pp. 4–5). Long cycle theorists saw long cycles as mechanisms of world system evolution. In situations of high evolutionary potential, the mechanism activated innovation and cooperation such that a sequence of long cycles resulted in the building of new global structures and toward the replacement of global leadership to increasingly institutionalized forms of world organization. This approach then focused not on a global system that achieved equilibrium but on the dynamic processes underlying it. The two global wars of the 20th century represented a “generation-long period of global conflict” that formed the world order of 1945 and brought the United States to the position of world power, which was actualized when American leaders, in the postwar period “declared their willingness to step into Britain’s place also on a peacetime basis” (Modelski, 1978, pp. 223–224).

Hegemonic transition theory and long cycle theory invested significance not just in military power but in the technologically innovative capacity of the hegemon. The former theory, in particular, held that hegemonic stability was underwritten by a capable and willing hegemon. Gilpin asserted that “the Pax Britannica and Pax Americana, like Pax Romana, ensured an international system of relative peace and security.” General prosperity was also ensured because “Great Britain and the United States created and enforced the rules of a liberal international economic order (Gilpin, 1981, p. 144). Emphasizing this point, Robert Keohane argued that while the bipolar lens captured important elements of the globalized military conflict between the superpowers, this view was less useful in explaining the workings of world political economy than was hegemonic stability theory (Keohane, 2005). Keohane, however, called for a reexamination of the latter theory. The two central propositions of hegemonic stability theory, he argued, were that “order in world politics is created by a single dominant power” and that “maintenance of order require[d] continued hegemony” (Keohane, 2005, p. 31). Keohane questioned the second proposition. With growing international economic interdependence among states in the 1970s, Keohane asked why, contrary to the theory’s expectation, such interdependence “continued to grow, and the pace of increased U.S. involvement in the world economy even accelerated after 1970,” at a time when “U.S. dominance in the world political economy was challenged by the economic recovery and increasing unity of Europe and by the rapid economic growth of Japan” (Keohane, 2005, p. 9). While neither easy nor automatic, non-hegemonic cooperation, he suggested, was facilitated by the continued existence of international economic regimes that had been created by the United States in the postwar period. Information-providing international institutions eased the pathway to interstate cooperation by reducing uncertainty even after the erosion of US economic dominance (Keohane, 2005, pp. 244–245). This approach came to be called neo-liberal institutionalism.

Following a different pathway, liberal theorists contended with the hegemonic implications of bipolarity by contrasting U.S. and Soviet leadership styles in their respective alliance systems. Bipolarity in the Cold War context represented a systemic condition wherein two superpowers—the United States and the USSR—were locked in an attitude of confrontation for over four decades. In this contest, the spatial geopolitical battles over spheres of influence were supplemented on both sides by universalist claims based on socio-economic doctrines (Brown, 2009; Service, 2007; Wade, 2003). Soviet leaders sought to make the globe a hospitable harbor for communism, and their American counterparts attempted to make the world safe for markets and democracies. These rival claimants battled to gain adherents for their respective causes. The ideological dimension was an important defining element in this division as each superpower, within its bloc, not only secured hegemonic order, but also anchored polities and economies in its broader image and in consonance with its values.

The manner in which the United States and the USSR established hegemonies in their respective spheres of influence in Europe therefore came under scholarly scrutiny: Did American and Soviet principles of hegemonic rule differ, and if so, in what ways? Theoretical commitments were germane to these debates. Realists argued that hegemons, across time and space, exhibited common traits and modes of behavior and that the United States behaved no differently from other great powers (Mearsheimer, 2001). Liberals disagreed, noting that America’s Cold War era strategy coalesced around two grand bargains—a realist-oriented containment policy against the Soviet Union and a negotiated liberal hegemony vis-à-vis Western Europe (Ikenberry, 1989). The porous nature of this hegemony legitimized American power in Western Europe and Japan (Ikenberry, 1998/1999) and resulted in an “empire by invitation” (Lundestad,1999). Soft- (value-driven) and sticky- (economic attraction) power (Mead, 2004; Nye, 1990a) distinguished U.S. hegemonic control in Europe from that of the USSR.

The Soviet hold on its sphere of influence in Eastern Europe, scholars suggested, was jeopardized by the very nature and methods of control. Drawing on Hedley Bull’s typology (1977, pp. 213–225) of dominance, hegemony, and primacy, which delineated a descending gradation from coercive to non-coercive forms of power, Mark Kramer characterized early Soviet control over Eastern Europe as dominance, which entailed tight and pervasive control without constraints imposed by international law or norms. Stalinist-era “dominance” over Eastern Europe evolved after the mid-1950s into a “hegemonic” relationship relying upon looser forms of control and acceptance of limited international legal restraints with the prerogative to use armed force when necessary. However, Soviet failure to graduate to the level of primacy, wherein control is legitimized largely by noncoercive diplomatic and economic influence, undermined the durability of Soviet influence in Eastern Europe. Soviet leader Mikhail Gorbachev’s reform strategy of a controlled promotion of internal crises in Eastern European countries in an effort to re-order Moscow’s relationship with its bloc failed, leading to the demise of East European communism (Kramer, 1996, pp. 100, 118; Zubok, 2007).

The End of the Cold War and the Future of Bipolarity

The Cold War effectively ended when, with Gorbachev’s tacit acquiescence, the Berlin Wall was breached in November 1989. This watershed event was followed by successive revolutions in the Soviet satellite states of Eastern Europe that serially toppled communist governments. The demise of the USSR in December 1991, and thereby the formal collapse of one of the poles of the international system, definitively ended the era of bipolarity but opened the page on a new series of unresolved questions over the nature and shape of the post-Cold War era world: the salience of the variables of culture and identity; the likelihood of great power competition or cooperation; and the pressure on the state of economic and ecological imperatives in a globalizing world.

Clash of Civilizations: An Alternative to the Narrative of Bipolarity?

The idea that cultural and civilizational fault-lines in the world would generate the inter-state conflicts of the 21st century became a subject of contention when Samuel Huntington published an essay in Foreign Affairs (1993) followed by a book on the subject (1996). In these two works, Huntington stated that civilizational identities, which were the source of cultural affinities, represented the primary forces shaping patterns of cohesion, disintegration, and conflict in the post-Cold War world. The very forces of global economic integration, he argued, were unleashing countervailing forces of cultural assertion and civilizational consciousness. Characterizing the world as multi-civilizational and multi-polar, Huntington cautioned against blind belief in the idea that processes of modernization led teleologically to the formation of liberal and democratic politics. Instead, he suggested that modernization and Westernization were discrete phenomena and that the former was neither producing a universal civilization nor leading to the Westernization of states in non-Western societies. The balance of power between Western and non-Western civilizations was shifting in favor of the latter, with states rising in power in the Asian civilizational sphere. Cultural affinities would lead states within civilizations to coalesce around core states, and world order would be civilization-based. Future conflicts would arise in the fault lines separating civilizations, primarily between the standard-bearers of Western civilization and those of Islamic and Confucian civilizations. The West, he maintained, should therefore proceed from a recognition of the sui generis nature of Western civilization and should interact with the “rest,” mindful of the multicivilizational character of the world.

Rebuttals of Huntington’s claims were robust. Foreign Affairs devoted a section of its next issue (Comments: Responses to Samuel P. Huntington's “The Clash of Civilizations?”) to Huntington’s critics. Fouad Ajami questioned Huntington’s portrayal of “messy” civilizations as hermetically sealed uniform entities and noted that “civilizations do not control states, states control civilizations” (Ajami, 1993, p. 9). Mahbubani, while lauding the achievements of Western civilization, called for a close examination of the “structural weaknesses” in “core value systems and institutions” that helped explain why the West was perhaps “bringing about its relative decline by its own hand” (Mahbubani, 1993, p. 14). Kirkpatrick (1993, pp. 22, 24) raised issue with Huntington’s classification of civilizations asking, for instance, why “Western” included both European and North American variants and why Russia could not be classified as “Western.” Moreover, she asked, if modernization induced changes in people, societies, and politics, how could civilizations and cultures not change? Bartley (1993) questioned whether the greatest potential for conflict rested within rather than between civilizations and suggested the possibility that the West could prevail if Western democracies struck a “balance between realpolitik and moralism” (p. 18). Liu, pointing to the many hot wars raging around the world in the post-Cold War period, argued that interstate conflicts had their source in clashes of economic and political interests rather than between civilizations (Liu, 1993). Walt took Huntington to task for failing to explain why loyalties were “suddenly shifting from the level of nation-states to that of ‘civilizations’” and why this “alleged shift” would lead to “greater civilizational conflict” (Walt, 1997, p. 176).

Huntington’s much discussed thesis had been a riposte to Fukuyama’s essay “The End of History” in The National Interest (1989), in which Fukuyama argued that the defeat of communism represented the end of History—that the ideological battles of the 20th century had demonstrated the “triumph of the West, of the Western idea,” through the “total exhaustion of viable systematic alternatives to Western liberalism” (1989). As with Huntington’s essay, Fukuyama’s thesis invited a fair share of critics, including Huntington and Wieseltier, whose analyses appeared in the next issue of the magazine (Huntington, 1989; Wieseltier, 1989). Coming ahead of the revolutions in Eastern Europe, Fukuyama’s idea of Western triumphalism appeared prescient, much as Huntington’s notion of civilizational clash garnered even more attention after the al-Qaeda terrorist attacks in the United States in 2001. By the second decade of the 21st century, Fukuyama had to admit that the rise of identity groups and their push for recognition undermined the promise of liberalism (Menand, 2018).

The Rise of Global Challenges: Is the State Relevant?

Post-Cold War debates centered on the implications for states of globalization and the many global challenges, from nuclear proliferation and terrorism to pandemics and climate change. Writing in 1999, Jean-Marie Guéhenno suggested that “we may be at the beginning of a new paradigm of international relations” of a post-national world with “the conditions of a stable international order depend[ing] on the invention of new political institutions” that would be “able to combine the leadership . . . traditionally . . . associated with nation-states with an organized interdependence based on a global rule of law” (Guéhenno, 1999, p. 35). A world of global challenges, in this view, could be tackled only by new global institutions working with states, a task at which, according to Goldin (2013), states had failed.

Globalization, others argued, would reduce the power of the nation-state, end interstate warfare as a form of conflict resolution for at least a generation, and create “messy conflicts” that did not respect political borders. Hence, describing the world in terms of poles would be less and less descriptive (Brzezinski & Scowcroft, 2008). Richard Haass (2008) contended that the 21st century would be defined by nonpolarity, because power was diffuse and state actors were declining in influence even as non-state actors were increasing in prominence and impact. Whereas the United States had been a willing and able provider of public goods since becoming a global power, Maher (2018) argued that it was no longer clear if this continued to be the case. Given the increasing failure of the state to address pressing global problems, still others offered a novel idea: that power was shifting—downward from states to cities; outward from the public sector to networks of public, private, and civic actors; and globally along circuits of capital trade and innovation, generating the dynamics of a new localism (Katz & Nowak, 2018).

While the ability and willingness of states to address threats of global scope may have waned, states have continued to be the primary locus of political and economic power in the world, and thus scholarly inquiry into questions of the state, power, and polarity have continued apace.

Unipolarity, Multipolarity, or Bipolarity Redux?

The Soviet decision to withdraw unilaterally from fighting the Cold War did not automatically erase the USSR’s formidable and extant military capabilities but pointed to an abdication of a global leadership role. Economic stringencies dented the Soviet, and later Russian, ability to maintain and modernize their military. From the perspective of polarity and great power competition, the significant characteristic of the last decade of the 1990s and the first decade of the 2000s was the Soviet/Russian retraction of influence from Europe and Asia and the gradual rise of China as a peer-competitor to the United States. These developments generated debate over whether the Soviet demise changed the system structure, by default, to a condition of unipolarity.

Realist and neorealist scholars variously characterized the post-Cold War period as inaugurating a unipolar moment (Krauthammer, 1990), a uni-multipolar arrangement (Huntington, 1989), a stable and enduring American unipolarity based on the unprecedented preponderance of U.S. power and America’s geographical distance from emerging regional powers (Brooks & Wohlforth, 2008; Wohlforth, 1999); an unstable unipolar order that would, at some time in the indefinite future, be challenged by rising powers (Waltz, 2000); and an emerging multipolar order with the increasing prominence of Europe (Kupchan, 2002) and of major powers in Asia (Brzezinski, 1997; Walt, 2005). Some suggested that, in a time when all major powers possessed nuclear weapons, international order was likely to be underpinned by a concert of powers (Rosecrance, 1992).

Liberal analysts like Nye (1990a, 1990b) and Ikenberry (2000, 2002) saw American unipolarity as helping to establish a cooperative, multilateral international order based on reciprocal obligations underpinned by law-governed institutions. Constructivists, on the other hand, explained the end of the Cold War as resulting from a change in Soviet identity, which in turn led to a redefinition of Soviet national interest, transforming the Soviet Union and then Russia into a Western partner (Wendt, 1992). Optimistic about the future of the post-Cold War world, constructivist scholars indicated the promise of cooperative possibilities in the socializing role of international norms that could lead to the creation of a putative, and over time perhaps a real, international community (Finnemore, 2003). Pushing back against this optimistic tide, Menon (2016), a realist, noted that a “normative” international community existed, if at all, only in “anemic” form and called attention to the “conceit” of humanitarian interventionists.

With evidence of declining U.S. primacy after the 2008 global financial crisis, scholarly research moved away from a focus on the unipolar moment and unipolarity. Under conditions of “unipolarity without hegemony” (Wilkinson, 1999), several works examined the strategies deployed by regional powers against the unilateral exercise of U.S. power globally (Hurrell, 2006; Nadkarni, 2010; Thies & Nieman, 2017 ), the shape of a post-American world (Zakaria, 2008), and the likely end of the American world order (Acharya, 2014). Other scholars contended that the United States, once touted as the indispensable nation, was in retreat (Bulmer-Thomas, 2018). Grygiel and Mitchell (2017)warned about the risks of US withdrawal from global leadership at a time when rising rivals, such as China, Russia, and Iran, sensing an opportunity, were seeking either to rebuild old empires or create new ones.

The phenomenon of China’s rise attracted great interest. Allison (2017), in considering whether a war between a rising China and declining United States was inevitable, argued that the two countries, given their respective narratives of exceptionalism, incompatible cultures and political systems, and many conflicts of interests risked going to war without robust efforts on both sides to avoid flashpoints that could embroil them in an escalating spiral of conflict. Yeisley (2011), on the other hand, highlighted the probability of proxy wars in Africa over resource access as the outcome of the coming U.S.-China bipolarity. Tunsjø (2018) asserted that there would be a greater likelihood of limited war and instability in a 21st century U.S.-China bipolar system. Maher (2018) noted that China did not have to equal the global reach of U.S. power and influence in order for the system to be considered bipolar. The international system would, in the near future, he stated, reflect “a condition of rough, or ‘loose’ bipolarity,” because China and the United States would “stand apart from the rest of the world in the coming decades; but the operation of U.S.-China bipolarity would differ from U.S.-Soviet bipolarity, because system structure did not determine state behavior (Maher, 2018, p. 497). The response of states to structural incentives was mediated by “the [i]nternal characteristics of leading powers, the nature of contemporary international politics, . . . and the underlying rules, institutions, and norms” of the international order (Maher, p. 500).

Maher’s analysis developed three main lines of argument: that the absence of a Chinese strategic threat to Europe on par with that of the Soviet Union, would weaken the structural incentives for Western European countries to align closely with the United States, while increasing the incentives for Asian states to ally with the United States; that global economic interdependence joined with intense global competition would act as a brake on U.S.-Chinese strategic competition; and that, significantly, at a time when “effective multilateralism” was essential in addressing global challenges, “conflict over the rules, procedures, and authority structures within global governance institutions” would be “more acute” than during the Cold War (Maher, p. 501). Christensen’s argument closely followed that of Maher’s: China’s rise, he noted, was real and even though U.S. power would not be eclipsed soon, Beijing’s assertiveness posed several strategic challenges, with the challenge to global governance being the greatest (Christensen, 2016).

Maher’s last concern also received the attention of other scholars who asked whether the new China-sponsored multilateral organizations, such as the Asian Infrastructure Investment Bank (AIIB), and the Belt-Road Initiative (BRI) represented significant long-term challenges to the Bretton Woods institutions underpinning the liberal international economic order established by the United States after the Second World War (Bowring, 2017; Rolland, 2017; Wang, 2016). Feng and He (2017, p. 23) examined China’s institutional challenges to the international order and concluded that Beijing pursued “two types of institutional balancing strategies”—inclusiveness when it enjoyed a “relatively advantageous status” (in the economic and trade areas), but exclusiveness when faced with a security challenge with disadvantageous prospects. Where do all these scholarly forays leave us?

Conclusion: Unresolved Questions

Chinese scholar Yan Xuetong’s comments offer an apt coda to assessments of the nature of the post-Cold War world (2018). Yan unequivocally declared that the “post-Cold War interregnum of U.S. hegemony” had ended, and bipolarity was “set to return, with China playing the role of the junior superpower.” He anticipated the transition to be “tumultuous, perhaps even violent,” with “China’s rise” setting the country on a “collision course with the United States.” He added, however, that Beijing had “no clear plan” for filling the “leadership vacuum” left by Washington’s slow retreat from “diplomatic and military engagements abroad.” Rejecting the view of U.S.-China bipolarity as presaging a “world on the brink of apocalyptic war,” Yan pointed to the narrow range of Chinese ambitions with a focus on economic growth and therefore an unwillingness to enter into open confrontation either with the United States or its allies but noted that proxy wars were likely (Yan, 2018, pp. 40, 45). Rather, than replicate the U.S.-Soviet “bipolarization” reflected in opposing alliances, Yan anticipated a period of uneasy peace characterized by bilateral U.S.-China competition in the “economic and technological realms.” “[N]ationalist populism in the West and China’s commitment to national sovereignty” would undermine “sustained multilateralism outside strictly economic realms” (p. 40). China, he argued, was unlikely to engage in revisionist moves to upend the “global network of trade ties” on which its prosperity depended, but neither was China interested in fashioning itself as the “global liberal order’s new custodian” (p. 44). International order under U.S.-Chinese bipolarity would be “shaped by fluid issue-specific alliances rather than rigid opposing blocs divided along clear ideological lines” (p. 46). Yan’s presentation of the Chinese world view provides a useful guidepost to directions for future research.

Scholarly analyses regarding the 21st century international order center on several as-yet unresolved questions: Will the United States be able and willing to manage the entry of a rising power like China, a resurgent power like Russia, and an emerging power like India, or is the military and diplomatic global retrenchment of the United States likely to continue? Will Western liberal values that underpin the current international order be challenged by America’s competitors in Asia and elsewhere? What will be the fate of the international liberal order if the United States were to abdicate leadership? This last question, considered in an edited volume (Jervis, Francis, Rovner, & Labrosse, 2018), has taken on greater urgency since President Trump’s prioritization of an “America First” foreign policy has resulted in a U.S. retreat from the world and opened the space for China to assert its power and press its strategic interests. Above all, would a rising China eventually seek to replace Pax Americana with a Pax Sinica, and would China be able, willing, and successful in establishing a Sino-centric world order? What would the ordering principles of a Pax Sinica entail? Careful scholarship underpinned by empirical research is necessary to ascertain if the norms that underpin the current international order will yield to the cultural value matrices of rising powers, such as China, and whether preoccupations with culture and identity will fuel xenophobia and nationalism that will derail the postwar Western liberal order. Scholars also need to examine whether the incentive structures at the domestic, regional, and global levels will propel rising states to act as status quo or revisionist powers, to assess the probabilities for competition/conflict/war and cooperation/peace, and to ask whether powerful states at the top are able to offer multilateral solutions to fend off global challenges.

In 2007, James Mann had cautioned Western leaders against the facile expectation that as China became enmeshed in a globalized economy, the country would embrace democracy. Mann was proven right as China has remained stubbornly authoritarian. At the close of the second decade of the 21st century, with a tide of democratic backsliding, and illiberalism rising, not only in the non-Western but also the Western world, we have to ask whether the triumph of political and economic liberalism that Fukuyama trumpeted at the end of the Cold War was premature, or whether liberal setbacks are temporary and, above all, to examine how and in what ways the role of the state, power, and polarity are likely to affect world politics in the unfolding 21st century.

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