XI JINPING is determined to take China into a new era that sets his country and the United States apart from other powers and avoids conflict between the two. The widespread view found in the works of, among others, Henry Kissinger, Graham Allison at Harvard University and John J. Mearsheimer at Chicago University is that U.S.-China relations are ripe for conflict and war. Their assumptions are based on analogies of great power conflict and power transitions under previous multipolar systems, such as prior to World War I. However, the United States and China are not rivals in a multipolar system. International politics has entered a new era in which the United States and China are the two lone superpowers in a bipolar system. China has risen to top-ranking status, and the both nations are much more powerful than any third state. Instead of comparing U.S.-China relations to great power rivalry in the past, the question we should ask is somewhat different: whether the superpower rivalry between the United States and China in the first half of the twenty-first century will resemble the stability that characterized the U.S.-Soviet Union superpower rivalry in the second half of the twentieth century.

With the return of bipolarity, we might expect another period of what historian John Lewis Gaddis termed “the long peace” of the previous bipolar system between the United States and Soviet Union. Political scientists have argued that a bipolar system of two is more stable than a multipolar system of three or more, but no one has examined the relative stability of bipolar systems. While it is important whether the international system is bipolar or has some other structure, stability is heavily affected by geopolitics and how geography shapes the two superpowers and their relationship. Since the previous U.S.-Soviet bipolar system and the new U.S.-China bipolar system are concentrated on two different geographic regions, systemic effects differ. The likelihood of limited war and instability is higher in a new U.S.-China bipolar system in the twenty-first century compared to the old U.S.-Soviet Union bipolar system of the twentieth. Water barriers in East Asia may prevent a third world war between the superpowers, but since the rivalry between the United States and China is mainly at sea instead of on land in Europe, it makes a limited war for the control and access to sea-lanes in maritime East Asia more likely.

TWO FACTORS suggest that that the international system has returned to bipolarity. First, the power gap between the United States and China has narrowed considerably during the last two decades. China’s nominal GDP currently accounts for about 65 percent of that of the United States’ own GDP. This contrasts sharply with the early 1990s, when the U.S. nominal GDP was about fifteen times larger than China’s. Currently, U.S. military spending is about two to three times that of China’s. This differs from the year 2000, when the U.S. defense budget was more than ten times that of China’s, not to mention the early 1990s, when U.S. defense expenditure was more than twenty times higher. While China has not obtained power parity with the United States, the relative increase in China’s combined power places it in the top ranking with the United States, even if only barely. Similarly, the Soviet Union was never as powerful as the United States, but it was still regarded as a superpower and a pole in the old bipolar system.

Second, no other states match China’s power in the aggregate, and the top two states are now much more powerful than any third state. In 2018, according to the International Monetary Fund, China’s nominal GDP was about ten times larger than Russia’s and roughly five times larger than India’s. The Chinese economy is almost three times as large as Japan’s, more than three times as large as Germany’s, and more than four times as large as France’s and Great Britain’s. It is wrong to argue that the international system is multipolar when Russia has about one-tenth and India has about one-fifth of China’s nominal GDP while China has reached more than three-fifths of the U.S. nominal GDP.

The Stockholm International Peace Research Institute (SIPRI) estimated in 2017 that China’s and Russia’s defense spending amounted to $228 billion and $55 billion respectively. China’s defense budget is roughly four times India’s, Great Britain’s and France’s and almost six times larger than Germany’s and Japan’s, also estimated by SIPRI. The power gap between China and the power next in rank has become so large as to warrant the notion of a new bipolar system.

It was the decline in Great Britain’s relative power and the power gap between the Soviet Union and Great Britain that transformed the international system from multipolar to bipolar in the post-World War II period. In Hans J. Morgenthau’s second edition of Politics Among Nations, published in 1954, he added, concerning the decline of the relative power of Great Britain, that the United States and the Soviet Union, “in view of their enormous superiority over the power next in rank, deserved to be called superpowers.” This is an important but often underemphasized point in the current debate, which focuses on whether China’s combined capabilities are sufficient for top-ranking status but neglects to measure the power gap between China and the power next in rank. The contemporary distribution of power among states is roughly similar to the power distribution at the start of the previous bipolar era in 1950.

MOST SCHOLARS and commentators examine contemporary U.S.-China rivalry from a multipolar perspective. Kissinger argues that the emergence of China poses a comparable structural challenge in the twenty-first century as Germany’s emergence posed a challenge to the system in twentieth-century Europe. However, Germany rose within a multipolar system that allowed for instability and a balancing behavior through arms racing and alliances, which contributed to the outbreak of World War I. In contrast to the rigid alliance system that prior to World War I—which compelled Germany to support its ally, Austria-Hungary, and compelled France and Russia to mobilize their armies in support of each other—China and the United States are not pushed in similar ways to support their respective partner (Russia) and ally (Japan) today. The United States and China are much more powerful relative to any other states and are not dependent on any alliances. Just like the previous Cold War period, they can concentrate their efforts on internal balancing, which is more likely to foster stability.

Equally important, prior to the Second World War the United States counted on balancing among European powers. However, this multipolar system promoted buck-passing among the great European powers, which allowed a rising Germany to start World War II. No European power confronted Germany before it invaded Poland. Great Britain, France and the Soviet Union were all hoping that other powers would stop Hitler. Since China is the only contemporary peer competitor to the United States, and the only power that can contend for regional hegemony on the Eurasian landmass, it is unlikely that the United States will pursue buck-passing today. Instead, the bipolar international system compels the United States to balance China.

China’s GDP and defense spending is roughly equal to the combined GDP and defense spending of all East Asian states, including Russia and India. Just so, the United States in the late 1940s was pushed to balance the Soviet Union since no other European powers could match its power. Stability and balancing differs under bipolar and multipolar systems, and the rise of China does not pose the same structural challenge today as Germany did in the past. This is often neglected in contemporary assessments of U.S.-China rivalry. Britain and Germany’s rivalry in a multipolar system led to two world wars, while the United States and Soviet Union’s intense confrontation sustained a cold war. The U.S.-China bipolar rivalry will have its own unique characteristics.

In Graham Allison’s most recent book, Destined for War, we are told that war between the United States and China in the decades ahead is not just possible, but much more likely than recognized at the moment, even if it is not inevitable. The conclusion draws on his examination of great power transitions over the past five hundred years, which shows that in twelve of sixteen cases the result was war. However, the cases that led to war were within multipolar systems, and Allison does not take into account the bipolar-stability thesis. In Allison’s dataset, the U.S.-Soviet case during the previous bipolar system did not end in war, which might suggest that the United States and China are destined for another “long peace,” not war.

THE RETURN of bipolarity matters if we want to gauge the possibility of war between the United States and China over the course of the twenty-first century. When we, for the first time, can compare the stability of two bipolar systems, we find variations primarily because of the geopolitical differences between a bipolar system concentrated on East Asia rather than Europe and with superpower rivalry concentrated more on the maritime domain than on land.

When comparing the bipolar systems in the twentieth and the twenty-first century we find that the risk of a limited war in Europe was low because of the extreme risk of it escalating to all-out war. The risk of a limited war in East Asia is higher because it is unlikely to escalate to all-out war. After Germany’s division and NATO’s and the Warsaw Pact’s respective establishment, Europe was split into two blocs. By the 1950s, a third world war was expected should either side invade the other. The stakes of inadvertent escalation were so high that they effectively stabilized the European continent. The Soviet Armed Forces, which only a few years prior to the Cold War had defeated Nazi Germany’s Wehrmacht in the greatest land battles in human history, posed an overwhelming threat to U.S. forces and allies in Europe. Its inability to match Soviet conventional army forces in Europe compelled the United States to introduce the principle of “massive retaliation,” which sought to deter limited war in the 1950s by threatening all-out war.

The United States is not similarly committed in East Asian waters today. The use of military force by the People’s Liberation Army (PLA) in East Asian waters is unlikely to pose an existential threat and risk a nuclear war. Washington can instead rely on its naval preponderance. It has not developed any strategy akin to “massive retaliation” to deter China and the PLA. Although China might use nuclear weapons if invaded and Beijing were occupied, it is much less likely, almost inconceivable, that Chinese leaders would risk a nuclear war with the United States because some of its naval ships were destroyed. In contrast to continental Europe, water barriers in East Asia makes China, the United States and U.S. maritime allies less concerned about survival and existential threats. Under these conditions, decisionmakers in the United States and China might be willing to risk war to solve maritime disputes in East Asia or launch a first strike against an opponent’s navy, calculating that a full-scale invasion or all-out war was less likely than if the superpowers were located on the same landmass.

Since U.S. deterrence relied strongly on nuclear weapons in the early years of the previous bipolar era, it made the threat of nuclear war more credible and strengthened stability in Europe. Because the U.S. military does not need to fight the PLA on the East Asian mainland to maintain a regional balance of power, the United States remains not only superior to China in nuclear capability but also at the conventional level. This makes a limited war more likely, since the U.S. threshold for using military force may not include the use of nuclear forces. Moreover, Chinese leaders, counting on their second-strike capability to prevent all-out nuclear war and on their belief in a clear firebreak between conventional and nuclear conflict, could interpret this situation such that they may risk a conventional first strike or a limited war at their own choosing, believing such adventurism would not spark a major or nuclear war. Soviet leaders in the 1950s, and even after Washington introduced its flexible response and countervailing strategy in the 1960s, could not rule out to the same extent that the United States would not use nuclear weapons in a limited war.

OTHER GEOGRAPHICAL conditions heighten the risk of limited war and will shape the relationship between the two poles in the twenty-first century. There are few periods in modern history in which a secure, dominating land power could focus on developing naval power and eventually sea power, as China has done today. It is unthinkable that any of China’s neighboring states would even consider invading China along its borders. In comparison to the Soviet Union, contemporary China has more secure borders, better access to the sea and is geographically more centrally placed in East Asia, with more favorable internal lines of communication to support its naval fleets and defend its territory. Geopolitics facilitates China’s maritime expansion, allows China to challenge the status quo in East Asia, fuels geopolitical friction between China and the United States and increases the risk of limited war. Without peer competitors on the Asian mainland, China can take greater risks in confronting the United States in East Asian waters. The result of the U.S. Navy and the PLA Navy increasingly interacting at sea is an intensification of rivalries and instability.

There was much more agreement about the status quo in Europe during the Cold War than there is in contemporary maritime Asia. The Soviet Union helped set the terms at the end of the Second World War, carved out its spheres of influence and shaped the regional balance of power in Europe. Today, China is rising within a system it did not shape. The separation of Taiwan from mainland China, among other outstanding territorial claims, adds weight to the longstanding view that contemporary China’s spheres of influence in the region do not reflect the country’s traditional regional dominance and suggests that Beijing will challenge the status quo. The Soviet Union did not claim territory in Western Europe or within the United States’ sphere of influence. China, on the other hand, has sovereign territory claims in maritime East Asia, which has long been the U.S. sphere of influence. This will increase instability in ways that were unseen in Europe and heighten the risk of crisis and limited war.

It is more difficult to draw red lines at sea. There is no East-West divide, no Berlin Wall and no Checkpoint Charlie in East Asian waters. There are no trip wires or commitments that are not inescapable. Instead, U.S. commitments around potential flashpoints in the South China Sea, the East China Sea and the Taiwan Strait are more uncertain. It is also harder to establish a security buffer at sea than on land. The sea cannot be conquered and occupied like land territories, as it is seamless and more difficult to control than land borders. Land intrusions can be repelled and territory retaken and restored. This is much more difficult at sea.

It is inherently more challenging to uphold the status quo at sea. For instance, during the stand-off with Soviet forces in Europe the United States did not face the ‘salami slicing’ tactic the Chinese government is using to challenge the status quo in East Asian waters today. Contemporary Chinese behavior is more difficult to deter since it does not threaten military invasion and includes the use of China’s maritime surveillance ships, coast guard and maritime militia.

The Soviet navy challenged the U.S. Navy at sea during the Cold War, but the two adversaries did not interact militarily within each other’s respective vital spheres of influence on the European continent in the bipolar era. U.S. tanks were not operating inside East Germany or East Berlin, and Soviet Armed Forces did not maneuver within the borders of NATO countries. In the new bipolar era, East Asian waters are the main contested area and theater of military operations. The fact that China and the United States will be peer competitors in the dynamic maritime domain increases the risk of limited war.

The contested area at sea in East Asia is a geographical space where a limited war between the superpowers can be largely confined to the maritime domain; where status quo and spheres of influence are challenged; where security buffers are lacking; where geopolitics provides the rising land power with opportunities to challenge the dominant sea power; but where polarity and geopolitics allow the United States to concentrate on balancing China’s regional ambitions. This makes a bipolar system concentrated in East Asia and U.S.-China relations more unstable than the previous bipolar system that was concentrated in Europe and U.S.-Soviet relations.

WITHIN A bipolar world, wrote Kenneth N. Waltz, “there are no peripheries.” Bipolar structural conditions suggest that any global event involves the interests of the two superpowers that are compelled to intervene across the world to safeguard their interests. A global zero-sum game follows from the condition of a two-power competition, argued Waltz. However, the sameness effect and the zero-sum thinking that are expected from a bipolar system are not evident in U.S.-China interaction in world affairs today. Similar geopolitical factors that heighten the risk of war in East Asia explain the different patterns of behavior by the United States and China as they compete for influence globally.

Geopolitical instability at the center in East Asia mainly accounts for diverging patterns of behavior. In contrast to the previous bipolar system, which experienced stability at the center in Europe and instability at the periphery or ‘third world,’ contemporary U.S.-China relations are set to be more unstable at the center in East Asia and more stable at the edges. Preoccupation with confrontation, instability and conflict in maritime East Asia is likely to prevent U.S.-China rivalry from becoming as intense in other regions of the world as U.S.-Soviet rivalry.

After Europe was stabilized into two blocs and spheres of influences during the early Cold War, the superpowers’ rivalry and conflict moved instead to other regions. The Korean Peninsula, Indochina, the Middle East, Africa, Latin America and Central Asia became theaters for the struggles and proxy wars of the two superpowers. In the new bipolar system, disputes in East Asia, from the Korean Peninsula to the East China Sea to Taiwan and the South China Sea remain unsettled and core concerns preventing superpower rivalry from spreading to other regions. Sino-American conflict in maritime East Asia will likely restrain global security confrontations and proxy wars in other regions that defined superpower relations during the Cold War.

Contemporary China remains concerned with its regional ambitions in East Asia, where it challenges the existing status quo and spheres of influence, protects its sovereignty claims in maritime East Asia, expands its presence at land and at sea, and seeks to establish a security buffer at sea by emphasizing the development of anti-access and area denial capabilities. Since East Asia does not resemble the East-West divide in Europe, a revisionist China is likely to be preoccupied with dominating the region and pushing the United States out of East Asian waters. In contrast, the Soviet Union was geopolitically rewarded in the post-World War II era and less interested in contending for regional hegemony in Europe.

There are fewer power vacuums to fill and less geographical space for China’s global interests to expand into. This explains why the U.S.-China rivalry and conflict on the global stage is evolving more gradually, and why China is more likely to focus on safeguarding and expanding its interests in East Asia. The shift from multipolarity to bipolarity in the post-World War II period saw traditional great powers like France and Britain lose their top-ranking position, opening the way for colonial revolutions, decolonization, civil wars and power vacuums. The two new post-World War II superpowers embarked on an intense decades-long rivalry to fill the power vacuums and gain influence in the numerous new states to appear. Colonial revolutions and decolonization created, in the words of Morgenthau, “a moral, military, and political no-man’s land neither completely nor irrevocable committed to either side.” The faith of the new “uncommitted nations,” whether they aligned themselves politically and militarily with the United States or the Soviet Union, sparked superpower rivalry on the global stage and created the two blocs and Non-Aligned Movement of the Cold War.

TODAY, NO empires are dissolving, there are no comparable colonial revolutions worldwide or power vacuums to fill. There are failed states and power vacuums in the contemporary world, but the instability in Africa, the Near and Middle East, Afghanistan and Latin America is not comparable with the instability in the aftermath of World War II and the decline of the traditional great powers. There is less geopolitical space for the superpowers to be pulled into and fewer newly developed states where the new superpower can compete for influence globally. Stability in Europe and power vacuums globally gave the Soviet Union an opportunity to compete globally with the United States despite the asymmetric power relationship between the Soviet Union and the United States. Instability in East Asia and smaller power vacuums globally prevent China from emulating the Soviet Union’s intervention globally.

In examining and predicting whether China and the United States will avoid the pattern of conflict and wars that marked the rise and the fall of great powers in the past, we need to establish whether China and the United States will be peer competitors within a bipolar or a multipolar system. This will affect the risk of war, stability, their pattern of behavior and how a new world order will be constructed. A bipolar system is a system in which no third power can challenge the top two. Not only has the unprecedented power shift during the last decade elevated China to superpower status, China’s leaders are now referring to a new era. China has risen well above the so-called BRICs emerging economies and has only one peer competitor: the United States.

The features of the previous bipolar system were stability, strong balancing, and strong competition and rivalry at the periphery. The contemporary bipolar system is characterized by instability, moderate balancing, and limited competition and rivalry at the periphery. A bipolar system concentrated on maritime East Asia in the twenty-first century is likely to be more unstable and prone to limited war than the bipolar system concentrated on continental Europe was in the twentieth century. Instability at the power center in East Asia is likely to foster more stability at the periphery than during the previous bipolar era since the superpowers are more likely to be preoccupied with rivalry in maritime East Asia and less likely to be involved in proxy wars in other regions. The new bipolar system is not destined for another “long peace.” While nothing is preordained in world politics, and the new structural conditions can be resisted, they are likely to push the United States and China toward a limited war for the control and access to sea-lanes in maritime East Asia.

Øystein Tunsjø is professor at the Norwegian Defence University College and the Norwegian Institute for Defence Studies. Tunsjø’s recent book is The Return of Bipolarity in World Politics: China, the United States and Geostructural Realism (Columbia University Press, 2018). Tunsjø holds a PhD in International Relations from the University of Wales, Aberystwyth and was a visiting Fulbright scholar at the Fairbank Center for Chinese Studies, Harvard University in 2010.

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