Back to Bipolarity: How China's Rise Transformed the Balance of Power

From fears of a “missile gap” and a rapidly growing Soviet economy, to “Japan as Number One” and China's rise, observers of international politics routinely debate the endurance of U.S. power in the face of rising challengers. Today is no exception—after four decades of China's economic rise, scholars and policymakers dispute the nature of the emerging system. Some say that unipolarity endures, that China will not become a “superpower” capable of overtaking the United States, or that Chinese power has peaked.¹ By contrast, some see China as a peer competitor and the United States’ “pacing challenge.”² Still others view the world as multipolar, pointing to Indian economic growth, Russian resurgence, and the emergence of other influential middle powers.³

Understanding the balance of power is critical. Great powers matter as a category because as they compete for influence and control, their activities powerfully affect global political stability, prosperity, and international order. The number of great powers matters, too. Scholars argue that different configurations of power (i.e., uni-, bi-, or multipolarity) bring different levels and types of dangers,⁴ and transitions in the balance of power raise the risk of crises and wars.⁵ Furthermore, arguments about polarity are often nested within broader foreign policy debates. Today in the United States, for example, some commentators advocate for the United States to arm Ukraine and Israel, whereas others urge Washington to prioritize its attention and resources on the superpower competition in Asia and require greater burden sharing by its allies.⁶

Although understanding polarity and the balance of power is vital, academic and popular debates exhibit significant discord about how to define and measure power and how much power a great power needs.⁷ Observers frequently debate great power rise and fall without identifying a threshold at which a state can be said to have joined the great power ranks.

What is the balance of power today? To contribute to this—and future—debates, this article creates a method for comparing national power. I use an inductive approach that relies on an agreed-upon list of great powers in previous international systems (1820–1990). I use this list to empirically validate common metrics of measuring power and identify thresholds that a country needs to surmount in order to join the great power ranks. Finally, I use this method to assess the contemporary balance.

This exercise yields three key findings. First, the historical analysis reflects significant imbalances in the global balance of power. Great powers often trailed the leading state substantially in terms of national capabilities: for example, with only a quarter or a third of the leading state's gross domestic product (GDP). Those countries nonetheless competed vigorously against other great powers and the leading state. Notably, the Soviet Union managed for decades to sustain a security competition that consumed the diplomatic and military energies of the United States, despite having only about 44 percent of U.S. GDP at the Soviet peak. Debates about China catching up or surpassing the United States thus use the wrong benchmark. Great powers need nowhere near parity with the leader to challenge it politically and militarily.

Second, the contemporary international system has shifted into bipolarity. Over the past two decades, China has risen to become a great power and a superpower. On the metrics validated here, China possesses capabilities as strong as—or far stronger—than those of typical great powers throughout history. China is thus capable of engaging in a serious security competition or war against the system's most powerful state. In fact, China is a superpower: one of the strongest countries in the world, with a large gap between it and the next most powerful state. On most metrics, China exceeds the Soviet Union at its peak, and the two countries share notable similarities in their great power portfolios. If the USSR was a superpower then, China is one today. The world is bipolar.

Third, today's international system has two great powers, not more, as commentators often assert.⁸ Japan and Germany possess great power economic capabilities but appear unlikely to build the military power required to put them in the great power ranks. India and Russia sit close to the economic thresholds but far below the threshold for military expenditure. These four countries are highly influential regional powers—but great powers they are not.

Findings from this article have important implications for international politics. First, the shift to bipolarity explains the deterioration in U.S.-China relations, which increasingly reflect the hyper-vigilant, hyper-competitive character of a bipolar competition. Superpower China will want to protect its global interests—interests that will often clash with those of the United States. Beijing will continue to advance its vision of international order for numerous issues (e.g., conflict resolution, human rights, international development and finance, peacekeeping, technology standards, and trade).⁹

Bipolarity will also likely transform U.S. grand strategy and alliances. The onset of unipolarity in the 1990s led the United States to expand its foreign policy ambitions, while many U.S. allies reduced their military capabilities.¹⁰ The North Atlantic Treaty Organization (NATO), in particular, grew increasingly lopsided in terms of leadership and resources. Now, as the international system has shifted into bipolarity, observers are questioning the sustainability of a U.S. grand strategy designed for a unipolar era.¹¹

This article develops these arguments as follows. I begin by describing how political scientists conceptualize and measure power. I next introduce a method for comparing national power, which, when used with data from historical systems, validates metrics for measuring power and identifies a threshold at which a rising state has joined the great power ranks. Section three applies this method to the contemporary system. Observers often argue that several trends (e.g., demographic, economic, and political) are slowing China's economic growth and will weaken it geopolitically and militarily.¹² I discuss this debate in the penultimate section. I argue that regardless of slowing growth, and regardless of whether it overtakes the United States, China is already capable of engaging in a serious security competition with it. Barring domestic political upheaval, China will remain a great power and a formidable geopolitical competitor into the foreseeable future.

Scholars and political leaders have long distinguished great powers for their outsized role in international politics. Robert Gilpin argues that great powers “establish and enforce the basic rules and rights that influence their own behavior and that of the lesser states in the system.”¹³ Historically, competition among the great powers led them to pursue imperialism, extraction, and colonization that inflicted vast suffering.¹⁴ Great powers fight wars that kill thousands, hundreds of thousands, or millions of people around the world. In the aftermath of wars, great powers draw borders and write rules of international order.¹⁵ Great powers vie for territory and influence, directly and indirectly.¹⁶ They subvert one another; they create spheres and buffers; they cultivate protégés, which they support materially and diplomatically;¹⁷ and they subvert uncooperative governments or support coup plotters in countries of strategic interest.¹⁸ Great powers “have an ongoing drive to expand their economic and commercial power spheres beyond their borders,” which they do by building navies and other power-projection forces.¹⁹ Although scholars expected the onset of nuclear technology to dampen great power competition, it continues apace.²⁰

The number of great powers in the world matters; scholars argue that unipolar, bipolar, and multipolar systems bring different levels and types of dangers.²¹ Some say that multipolar systems (three or more great powers) are the most unstable because they have the highest number of great powers, which increases the importance, fluidity, and uncertainty of alliance-making.

Bipolar systems, by contrast, feature two great powers.²² Hans Morgenthau argues that during the Cold War, the United States and the Soviet Union were “superpowers” (relative to the European great powers) because they had the strongest national capabilities in the world, and because of the vast gap between their power relative to the “next in rank.”²³ These two superpowers—with different domestic political systems, ideologies, and views of international order—presided over alliance systems and regional orders.²⁴

Scholars view bipolar systems as more stable because they lack the fluidity and miscalculation associated with multipolarity.²⁵ But superpowers, argues Barry Posen, are obsessed with each other's actions and with maintaining a favorable balance of economic, military, and technological power. All these traits, Posen writes, make bipolarity highly competitive: “a system of chronic overreaction.”²⁶ In the Cold War, the two superpowers competed for allies and influence and viewed the other's gains as losses.

The third type of system, unipolarity, characterized the international system after the collapse of the Soviet Union in the early 1990s. Some scholars suggest that a system with a single great power is the most stable of the three types. According to William Wohlforth, the unipole deters balancing and reduces the risk of war through miscalculation because it is easy for potential challengers to perceive its dominance.²⁷ Other scholars, however, warn that with its significant power advantage, the unipole may be tempted to frequently use force against smaller countries.²⁸ Because a shift to bipolarity or multipolarity would bring different dangers, it is vital to understand how the rise of China or other countries may have altered the international system.

The concept of power is often central to both foreign policy questions and international relations theories. The policy community, comments J. Dana Stuster, probably spends too little time thinking about a definition of great power, but “the academic community has arguably done too much,” producing a vast literature with proliferating definitions.²⁹ Indeed, the literature on national power is immense.³⁰ Scholars debate whether to conceptualize power as a country's ability to produce desired outcomes or to define and measure power as a set of capabilities a state possesses.³¹

Scholars advocating the latter discuss a range of material as well as nonmaterial capabilities. For material factors, scholars typically emphasize population size, economic wealth, technological capabilities, and military might.³² Military power stems from both conventional and nuclear forces.³³ Although material power is clearly important in great power competition and war-fighting, scholars note that battlefield performance is driven as much by the “software” of war-fighting as by “hardware.”³⁴ Nonmaterial sources of power include a country's organizational capacity, national unity, moral leadership, status, or soft power—a state's ability to get what it wants through attraction and emulation.³⁵

Scholars also debate how “great” a great power must be. For example, Jack Levy looks for a “high level of military capabilities relative to other states” and expects great powers to have “relative self-sufficiency with respect to security.”³⁶ John Mearsheimer writes that a great power has “sufficient military assets to put up a serious fight in an all-out conventional war against the most powerful state in the world.”³⁷ Paul Kennedy requires a great power to “[hold] its own against any other nation.”³⁸ Nuno Monteiro contends that a great power must be able to “engage unaided in sustained politico-military operations in at least one other relevant region of the globe beyond its own on a level similar to the most powerful state in the system.”³⁹ In sum, scholars disagree about both the ingredients of power and how much of it a great power needs.

Debates about power and great power also offer a variety of metrics for measuring the elusive concept of power. A method often used in the power transition literature is the Composite Index of National Capability (CINC).⁴⁰ This influential project relies on six indicators of demographic, economic, and military power. Though the index captures the vital dimension of a country's scale, scholars note that it omits a country's level of sophistication—in human capital, governance, organization, technology, and so forth.⁴¹ Thus, since the information age, the index has yielded dubious codings of the balance of power.

International relations scholars commonly rely on a handful of metrics to compare national power. To measure a country's overall demographic and economic scale, scholars often assess its aggregate GDP.⁴² This metric is regularly and (for most countries) reliably measured by international organizations.⁴³ Angus Maddison's project estimates GDP dating back hundreds of years.⁴⁴ For eras that predate GDP data, other scholars use proxies (e.g., energy consumption) to approximate a country's economic power.⁴⁵

Scholars argue that although GDP captures a country's aggregate economic scale, it fails to capture a country's economic sophistication. In other words, a large GDP might be the result of a huge population producing at subsistence levels. Such a country would likely lack the human capital, organization, technological skill, and surplus wealth (wealth above what is consumed) for discretionary spending such as military expenditure.⁴⁶ So GDP used alone risks overestimating the power of poor, populous countries. Arguing that attributes such as organizational capacity and surplus wealth are key components of national power, analysts often use GDP per capita as a proxy for a country's level of sophistication.

Michael Beckley argues that “gross” indicators such as CINC scores or GDP neglect to consider many important costs.⁴⁷ “A country with a big population,” Beckley writes, “might produce vast output and field a large army, but it also may bear massive welfare and security burdens that drain its wealth and bog down its military, leaving it with few resources for power projection abroad.”⁴⁸ Because both GDP and GDP per capita capture key dimensions of power, Beckley and other scholars recommend multiplying the two metrics together: GDP x GDP per capita (what I call the “composite” metric).⁴⁹

What about measuring military power? States might possess both conventional and nuclear capabilities for war-fighting.⁵⁰ The most compelling analyses of a state's ability to project power identify specific countries and analyze interactively their ability to prevail in a given mission against each other.⁵¹ But when comparing countries’ military power in a general sense, scholars typically reach for two common metrics related to the projection of conventional military power: a country's military expenditure and number of mobilized military personnel. Scholars warn, however, that these indicators do not capture a country's technological sophistication or battlefield effectiveness.⁵²

International relations scholars and policymakers evince little agreement about how to define or measure a key variable in international politics, but, as Edward Vose Gulick writes, “statesmen … must measure power, regardless of the primitive character of the scales at their disposal.”⁵³ This article contributes to current and future debates by creating an inductive method for comparing national power. To be clear, I neither define power nor offer new metrics for measuring it.

I begin with a list, generated by historians and political scientists, of great powers in different historical systems (1820–1990).⁵⁴ This list reflects a “high scholarly consensus on the composition of this oligarchy,” as well as consensus about historical periodization.⁵⁵ I take this list as ground truth: These are the great powers, according to scholars’ assessments of myriad great power attributes (material and nonmaterial). For each system I also note the country that scholars perceive as the leading state (see table 1).⁵⁶

I assess a country's national capabilities as a ratio relative to those of the leading state. Thus, the GDP metric is the ratio of a great power's GDP to the leading state's GDP. For the systems in which the United States was the leading state, I evaluate France's GDP ratio, for example, as France's GDP to U.S. GDP (see table 2).

With this method I make two contributions. First, it shows which of the metrics that scholars commonly use do a good job of approximating the list of countries that scholars believe to be great powers. For example, if GDP is a good measurement of great power, it should reliably re-create the list of great powers—in other words, the countries on that list should have large GDPs. If using the metric adds other countries that are not on the list, this suggests it is a flawed metric. For economic power, I assess three metrics: GDP, GDP per capita, and the composite metric of GDP x GDP per capita. For military power, I assess two metrics: military expenditure and military personnel. To perform well, a metric should reliably re-create the list of great powers while excluding non–great powers.

To be clear, these metrics are proxies for power—not definitions of power. The metrics that I assess all relate to a country's material power, but as noted, I offer neither a material nor nonmaterial definition of power; I offer no definition of power at all. Rather, my approach is inductive: I use agreed-upon lists of great powers in historical systems to assess which metrics reliably reconstruct those lists. When I conclude that the composite metric is a sound metric, that only means it is a good proxy for the highly multifaceted concept of power. Future research should explore which other metrics (including nonmaterial ones) perform well in re-creating these historical systems. For example, scholars sometimes measure a country's status using metrics related to diplomatic representation (i.e., a country's sending and receiving of diplomats of different ranks).⁵⁷ Scholars can validate other metrics related to nonmaterial or soft power using the method presented here.

A second contribution from this analysis is that it identifies a threshold for great power. Debates about great power rise often assert that a country is a great power or is no longer a great power, or that it is catching up with or faces a large gap vis-à-vis a more powerful state. Yet such discussions often lack a threshold at which a country can be said to have reached the great power ranks. By inductively identifying a threshold for great power, this article improves the field's understanding of the dynamic process of great power rise and decline. Understanding thresholds for great power also helps with retroactive analyses of international politics, as scholars continue to study how changes in the balance of power affect the likelihood of war and other phenomena.⁵⁸ The concept of a threshold also informs contemporary debates. Has China joined the great power ranks? Has it declined out of them? Do other countries (e.g., India, Japan, Russia) exceed the threshold for great power? A method that enables us to see those countries’ positions vis-à-vis great power thresholds—and on which metrics they are stronger or weaker—significantly enhances our understanding of world politics.

I use data from the previous historical systems to generate “dyad-decades” (a ratio of a given great power to a leading power calculated each decade). For GDP and GDP per capita data, I use economic data from Maddison's historical dataset.⁵⁹ I assess how much power a typical great power has relative to a leading state. Thus, I use the data to find what I call the “normal range” (i.e., the second and third quartiles) and the median of national capabilities among great powers. In other words, I measure how much power countries in the middle 50 percent of the distribution possess.

I first share results related to economic power. Data from 1820 and 1860–1990 yielded seventy-six dyad-decades. Table 3 shows the normal range and the median scores for great powers according to economic metrics. Since 1820, the typical great power had a GDP within 17–45 percent of the leading state's GDP, with a median of 27 percent. The median GDP per capita among great powers was 59 percent of the leader's. The historical record thus shows that the threshold for great power is low in terms of GDP, higher for GDP per capita, and very low (8 percent) for the composite metric.

As noted, one test of the validity of these metrics is whether they distinguish between great powers and non–great powers. To check this, I used the three economic metrics to compare the great powers (1) with all other countries, and (2) with middle powers, using data from 1820, 1870, and 1900–1990. This generates 969 observations (dyad-decades); results are in figure 1. The axis along the bottom of each panel represents the leading state: that is, 0–100 percent of the leading state's capabilities on that measure. This figure shows that two of the three metrics—GDP and the composite metric—successfully distinguish between great powers and other countries. As the middle panel shows, GDP per capita shows significant overlap among great powers, middle powers, and all non–great powers.

problems with the gdp per capita metric. This analysis shows that GDP per capita, which is commonly referenced in debates about great power, is not a sound metric for this purpose. To compare national capabilities, scholars understandably want to capture not just a country's aggregate economic scale but also its technological sophistication, organizational competence, and so forth. Scholars argue that GDP per capita correlates with such factors, and countries with higher GDPs per capita will have greater “surplus” or “mobilizable” wealth that can be devoted to geopolitical and military competition.⁶⁰

The metric, however, suffers from several problems. First, as shown in the middle panel of figure 1, GDP per capita does not distinguish great powers from other countries. Consequently, many countries have high GDPs per capita but are not great powers.⁶¹ The reverse is also true; countries sometimes have low GDPs per capita but are great powers—that is, they can develop the requisite cutting-edge technology to compete with other great powers. For example, in the years before World War II, the GDP per capita for Japan was below or at the low end of the normal range of 38–70 percent. But scholars recognize Japan as a great power that effectively mobilized and deployed a massive military and fielded advanced weapons technology.⁶² The Soviet Union, too, had a GDP per capita that peaked at 37 percent, and indeed was lower for most of the Cold War. Yet in the early Cold War, the USSR led the world in chemistry, mathematics, and physics, produced world-class space and nuclear technologies, and Soviet scientists won numerous Nobel prizes.⁶³ Soviet leaders funded technological activities by depriving their people of the basic products that support a middle-class lifestyle. In sum, income gaps are not determinative in great power competition if the trailing country can produce the leading technologies of the day.

As a metric of national power, GDP per capita also suffers from logical problems. For example, the metric is a proxy for a state's technological sophistication. But the metric offers a national average, which obscures a country's highest level of technological performance. This obfuscation is most misleading in countries with significant regional heterogeneity, such as the USSR in the 1950s. In such cases, a country might simultaneously have many poor people as well as sectors that produce cutting-edge technology. The use of GDP per capita would bring down the national average, obscuring technological sophistication in parts of the economy. In sum, although scholars understandably seek a measurement of a country's level of sophistication, GDP per capita is a flawed metric both logically and (as this article shows) empirically.

As described earlier, I evaluate the extent to which two metrics—military expenditure and military personnel—capture great power military capabilities. Data from historical systems (1820–1990) resulted in ninety-two dyad-decades, yielding the results shown in table 4. These data show that the median great power spent about half of the leading state's military expenditure, and historically raised much larger armies. That is, both leading states (the United Kingdom in the nineteenth century and the United States thereafter) raised smaller armies than other great powers.

These military metrics perform well in differentiating great powers from middle powers, as shown in figure 2. Whereas great powers spent 23–105 percent of the leading state's military expenditure, middle powers spent much less (2–13 percent). Similarly, middle powers raised vastly smaller armies.

These metrics also differentiate great powers from latent powers: countries with large populations and strong economic capabilities whose governments choose not to mobilize substantial military forces.⁶⁴ For example, Japan's economic development after World War II propelled the country past the threshold for great economic power. In 1980, Japan's composite score was 32 percent (well past the great power median of 15 percent). But Japan's military expenditure and military personnel (6 percent and 12 percent, respectively) were far below the thresholds for great power. Contemporary Germany, too, exceeds the threshold for great economic power, but its low level of military spending has kept it out of the great power ranks (as discussed below).

In sum, the inductive method introduced in this article relies on agreed-upon balances of power to evaluate metrics for measuring power and identify thresholds for great power. The military metrics, as well as the GDP and composite metrics, accurately replicate the balance of power and differentiate great powers from other countries. GDP per capita, however, is a flawed metric in debates about relative national power.

The following figures show the balance of power re-created by two metrics (the composite ratio and the military expenditure ratio) across multiple Historical systems. Figure 3 depicts the balance of power in the nineteenth century, and figures 4 and 5 show the balance of power in the twentieth century. Black circles denote countries that all appeared on the list of great powers; I include a few (in gray) that are absent from those lists. White circles denote leading states.

In each figure, the axis equals 100 percent of the leading state's power. The shaded zones indicate the normal range for great powers (i.e., the second and third quartiles, as noted in tables 3 and 4). States to the left of that normal range sit below the threshold for great power, whereas states to the right of it exceed the normal range (and thus are unusually strong on that dimension).

Critics might wonder whether the variables that I show capturing great power status in the nineteenth and twentieth centuries still measure countries’ capabilities today. One might argue that economic and military power have both changed, and thus the measures and thresholds derived from previous systems have little relevance in the twenty-first century. Indeed, the ingredients for an advanced economy have evolved substantially over time. A highly skilled workforce was not a requirement for becoming a world-class economy in the nineteenth century, but it is in 2024. My analysis merely assumes that economic might—whatever its sources—remains the foundation of power in international politics. The state draws on its economy to buy weaponry, to coerce, sanction, and bribe other countries, and thus to exert geopolitical influence. The weaponry required to compete militarily obviously varies dramatically from the nineteenth century to the present. But the underlying relationship—between a country's economic power and its ability to buy cutting-edge military weaponry and other tools of statecraft—remains valid.

In this section I use the metrics to assess the current balance of power. Observers variously argue that China is a great power trailing the United States, a superpower peer competitor, or a country in decline. People describe the world as unipolar, bipolar, and (referring to India and Russia), multipolar. The method created in this article informs this debate.

China's economic growth since the 1980s has shocked the world. After the Chinese Communist Party (CCP) initiated economic reforms in 1979 and improved its political relations with the West, the economy grew at about 10 percent per year until 2018. China's economy doubled in size every eight years during the 1979–2018 period.⁶⁵ As a result, the size of China's economy has overtaken that of the U.S. economy (measured in GDP adjusted for purchasing power parity, which accounts for lower prices in China). In nominal or market terms, China has the world's second-largest GDP after the United States. The method introduced in this article shows that China's economic capabilities already well exceed not only the median but the normal range for a great power. Table 5 situates China relative to previous great powers.

Figure 6 shows China's relative economic power compared with previous great powers and with the leading state (the United States). In terms of economic capabilities, China (indicated by the star) far exceeds the normal range (indicated by the solid lines) for great powers.

This method makes important contributions to debates about China's relative power. Without a threshold, observers cannot assess if China is not yet a great power, has already become a great power, or is in decline. For example, using the composite metric, Beckley argues that “China lags far behind the United States.”⁶⁶ China indeed trails the United States (even after updating Beckley's 2011 data); on the composite metric, China has 36 percent of U.S. economic power. Critically, however, my analysis shows that according to this metric, the median great power only had 15 percent of the leading state's power. China's score of 36 percent should thus be interpreted not as reflecting a dramatic gap between U.S. and Chinese capabilities, but rather as indicating that China is well past the great power threshold, and indeed more economically powerful than most of the great powers since the nineteenth century. Thus, by definition, China has the capability to engage in a dangerous competition with the leading state.

interpreting china's gdp per capita. China's GDP per capita (about $24,500 adjusted for purchasing power parity) is much lower than that of the United States and the world's other leading economies (figure 7). Observers of China's relatively low GDP per capita sometimes infer a large capabilities gap between China and the United States and other advanced economies. For example, arguing that “most of the country is still very poor,” Salvatore Babones concludes, “The idea that China poses a serious economic (and thus military) challenge to the United States is simply preposterous.”⁶⁷

But China's GDP per capita tells us little about its ability to compete geopolitically against the United States. To be sure, analysts are correct when they argue that low GDP per capita reflects a lower standard of living relative to other countries. But this article shows that GDP per capita is a poor indicator of relative national power for several reasons.

First, the problem of GDP per capita obscuring regional heterogeneity is particularly glaring in China's case. China's southeastern coastal provinces (near Hong Kong and Taiwan) benefited the most from the country's export manufacturing push and have much higher levels of development relative to interior provinces. There are multiple Chinas: hundreds of millions of people who live in a low GDP per capita society, and hundreds of millions of others who live at a level comparable to developed countries. Of course, even the most developed Chinese cities lag the world's wealthiest urban areas. But assessing China's GDP per capita as low obscures the much higher GDP per capita in cities such as Beijing and Shanghai, where a country-size population (i.e., about 50 million people) lives (see figure 8).

To put it differently, the GDP per capita statistic encourages us to think of China as a country with 1.4 billion Belarusians (i.e., a country near China in GDP per capita rankings). But it is more accurate to say that China is comprised of many Belaruses, several poorer Tajikistans, and a South Korea.

china's technological capabilities. Readers might wonder to what extent the method in this article captures a country's technological capabilities—a vital dimension of great power.⁶⁸ As noted, the non-technological metrics successfully re-create the balance of power among what were the world's most technologically advanced countries.

Other assessments support the view that China has emerged as a technological leader.⁶⁹ In the past decade, on a variety of metrics used to measure national innovative capacity, China has become one of the world's most advanced countries.⁷⁰ For example, China ranks highly in high-technology exports, human capital, patenting, R&D spending, and scientific research.⁷¹ “China has built the foundations to position itself as the world's leading science and technology superpower,” argued a 2023 report from the Australian Strategic Policy Institute, “establishing a sometimes stunning lead in high-impact research across the majority of critical and emerging technology domains.”⁷² This and other research points to China and the United States as the two global leaders in emerging technologies, such as artificial intelligence (AI), biotechnology, and green technologies.⁷³ China is also successfully adapting to U.S. export controls aimed at depriving China of cutting-edge semiconductor technology, making significant progress in that sector as well as in the technologies that depend on it.⁷⁴

Given numerous U.S. strengths, analysts argue that China will struggle to overtake the United States in terms of innovation.⁷⁵ Yet a key insight of this article is that “catching up” or “overtaking” are the wrong benchmarks. China need not do either; as one of the world's most technologically advanced countries, it has the ability to engage the United States in a punishing great power competition.

While watching China's economic rise, observers debated whether a great power China would accept the international order or emerge as a “revisionist” state.⁷⁶ Scholars disaggregate different facets of international order (e.g., security order, global governance, human rights) and note that rising powers might accept international order on some dimensions while challenging others.⁷⁷ This article shows one dimension of Chinese revisionism: the military balance of power.⁷⁸ China's economic rise and military buildup have shifted the balance of power from unipolarity to bipolarity. In this respect, China's behavior departs notably from two other rising powers after World War II: Japan and (West) Germany. Both countries developed significant latent power, yet neither challenged the status quo military balance.

Measuring Chinese military power is challenging, even according to the seemingly straightforward metrics used in this article. Analysts note that Beijing's defense accounting differs from the method used by the United States and NATO; that Beijing does not report all of its defense expenditures; and that the nominal statistics analysts typically use to discuss defense expenditures understate China's capabilities because it pays many of its expenses (notably salaries of military personnel) in local currency. If China's military expenditure were adjusted for purchasing power parity, it would increase “by well over $100 billion.”⁷⁹ Furthermore, the China Coast Guard—actively involved in interstate territorial disputes—organizationally sits under the control of the People's Armed Police, an internal security agency whose funds are not reflected in the military budget.⁸⁰

But we do our best, despite what Gulick calls the “primitive character of the scales at [our] disposal.”⁸¹ As depicted in figure 9, China lies within the normal range for great powers for both military expenditure (at 32 percent) and military personnel (153 percent). Scholars correctly point out that China is far from matching U.S. military capabilities.⁸² But as this article argues, even though a great power may trail the leading state significantly, by definition it can engage the leading state in dangerous security competitions and wars. According to the military metrics evaluated here, China is a great power capable of doing both.

china's military rise. Qualitative assessments of Chinese military capabilities support the finding that China has become a great power. The CCP embarked on a major military modernization effort starting in the 1990s, downsizing its massive and antiquated army and expanding its maritime capabilities.⁸³ This modernization built formidable Chinese conventional military forces, created the connective tissue that increases the lethality of conventional military power, and gave China a world-class nuclear arsenal.

First, China has transformed its conventional military capabilities, particularly in air, naval, and precision strike. In a short period, the People's Liberation Army Air Force (PLAAF) has transitioned from flying MiG-21s to building and flying fifth-generation stealth J-20s. Over time, the PLAAF shifted to “a more expansive role encompassing both defensive and offensive operations at greater distances from China's land borders.”⁸⁴ The People's Liberation Army Navy has become the world's largest in terms of tonnage and has commissioned four aircraft carriers and sophisticated destroyers for blue-water operations throughout the region. China's conventional ballistic missile force is unmatched in the world, giving China the ability to precisely strike targets throughout Asia.⁸⁵

Second, China has developed the connective tissue that makes conventional forces more lethal. This includes a global intelligence, surveillance, and reconnaissance system that relies on the largest global constellation of satellites controlled by any country other than the United States.⁸⁶ Researchers describe China as a peer competitor of the United States in cyber and electronic warfare capabilities.⁸⁷ China has also invested in battlefield command and control, including advanced airborne warning and control aircraft and unmanned aerial vehicles.⁸⁸ In space, “The United States is once again facing a singularly prominent contender—this time China,” writes Saadia Pekkanen, which has “expanding dual-use capabilities in space, and a demonstrable will to lead in space affairs.”⁸⁹

Third, China has transformed itself from a third-rate nuclear power—whose nuclear forces could barely guarantee an assured retaliation capability—to one of the world's three leading nuclear states.⁹⁰ China's nuclear arsenal is growing faster than any other arsenal in the world. Its quantitative growth is matched by breakthroughs in delivery systems—potentially including hypersonic missiles and fractional orbital bombardment systems—that would give China meaningful advantages in the emerging nuclear competition.⁹¹

Although China's military power has undoubtedly grown, could its forces fight effectively? Russia's stumbles during its 2022 invasion of Ukraine spotlighted the vital “software” of war-fighting, related to the skill of personnel, morale, information flows, jointness, and logistics.⁹² Chinese leaders worry about what they call “peace disease”: the fact that the People's Liberation Army (PLA) has not fought a battle since 1979 and has never fought the kinds of joint operations that a war against Taiwan would require.⁹³ Toward the goal of improving PLA war-fighting capabilities, Chinese leader Xi Jinping in 2015 ordered major military reforms.⁹⁴ Additionally, multiple rounds of reforms of the defense industry have improved the efficiency and quality of this previously inefficient sector.⁹⁵

Serious questions remain about the PLA's war-fighting abilities against the formidable U.S. military. Indeed, great powers have historically varied significantly in their military effectiveness. Nonetheless, by building great power military forces, China has put itself in the game. Its heavy investments in air and naval power, precision strike, satellites and other surveillance systems, and burgeoning nuclear arsenal have shifted the regional military balance such that the United States would have great difficulty projecting effective military force into East Asia during a war.⁹⁶

This article's assessment of China as a great power is also supported by nonmaterial factors. First, as many scholars predicted, China's ambitions and assertiveness have risen along with its material capabilities. This is a significant change from the 1990s, when Chinese leaders proclaimed a “peaceful rise” and scholars noted Beijing's reassuring behavior.⁹⁷ Today, however, “it is now difficult to deny that Beijing seeks to be the predominant power of Asia and wants to exercise a veto over the most important military and geopolitical actions of other countries.”⁹⁸ China's Coast Guard, as well as military aircraft and naval vessels, venture into neighbors’ territorial waters or disputed areas, using intimidation and force.⁹⁹ The CCP's national security narrative envisions “a fully developed, rich and powerful nation” with “world-class military forces” by 2049—a nation that has “reunited” territories lost during the “Century of Humiliation.”¹⁰⁰ Acquiring these territories would likely require the use of force against Taiwan and China's neighbors over disputes in the South China Sea.

As China's material power has grown, so too has its status and influence.¹⁰¹ China's currency has grown more influential in international trade and finance.¹⁰² Diplomatically, as Oriana Skylar Mastro notes, China doubled its memberships in international institutions from 1990 to 2010. It has become a leader in the United Nations, normalized relations with twenty-eight countries during the 1990s, and “went from diplomatic isolation to having as much diplomatic and political power on the world stage as the United States (by some measures, slightly more).”¹⁰³ Beijing is actively asserting leadership over technological standards,¹⁰⁴ human rights,¹⁰⁵ peacekeeping and conflict resolution,¹⁰⁶ and economic development.¹⁰⁷ China's leadership—its presentation of itself as an alternative to the “hegemonist” United States—has strong appeal in many countries.¹⁰⁸ Thus, China's nonmaterial power has grown with its material capabilities.

Some observers argue that even if China has become a great power, the United States occupies a category all of its own: a superpower with a profound economic, technological, and military lead, and command of the global “commons.”¹⁰⁹ This view rests on the claim that a great power must have rough parity with the leader to compete effectively against it. It also rests on a definition of a superpower as having attributes China lacks (e.g., regional hegemony, global power-projection capabilities, a large network of allies).¹¹⁰ In this skeptical view, China—a great power, not a superpower—will be unable to compete effectively against the United States.

By contrast, this article argues that China is a superpower and the world is bipolar. The historical data show that wide gaps in capabilities, and the possession of very different kinds of power, are common among great powers. As Joshua Shifrinson notes, “Throughout history, great powers have never been thought of as quantitative peers.”¹¹¹ Even superpowers show significant disparity in national capabilities. During the Cold War, the Soviet Union was weaker than the United States on some dimensions, as China is today. At its peak, Soviet GDP was only 37 percent of U.S. GDP. “Polarity,” observes Posen, “is not synonymous with equality…. The Soviet Union was only barely in the league of the United States for most of the cold war in terms of economic capacity, yet we think of the era as a bipolar order.”¹¹²

This analysis also supports that view that the best way to define a superpower is not through various attributes it possesses. Øystein Tunsjø shows that regional hegemony, global military capabilities, alliance systems, or nuclear weapons do not by themselves capture the concept of a superpower.¹¹³ Instead (following Hans Morgenthau and Kenneth Waltz), he argues that a superpower is best measured by the distribution of capabilities. That is, superpowers both possess some of the strongest material capabilities in the system and significantly outdistance the capabilities of the next most powerful state. “The United States and the Soviet Union,” Tunsjø writes of the Cold War, “were not only top-tier powers because of their preponderant capabilities but also because of their relative superiority over Great Britain, the third-ranking power.”¹¹⁴

In analyzing the distribution of capabilities, this article shows that today the international system has two superpowers, China and the United States: They have preponderant capabilities within the system, and their capabilities significantly outdistance those of the next most capable state. Figures 10 and 11 depict the contemporary balance. Aside from the leading state (United States), China is the only country that meets the threshold for great power on all economic and military dimensions in this study. The world is bipolar.

comparing two bipolar systems. A comparison with another superpower in a previous bipolar era, the Cold War, also supports the finding of a bipolar system today.¹¹⁵ As noted, scholars routinely characterize the Cold War as a bipolar system with two superpowers: the Soviet Union and the United States. Today, China exceeds the Soviet Union on almost every dimension of national power. China has vastly stronger economic capabilities than the Soviet Union ever did. China lags the Soviets only for military expenditure, but, importantly, China spends an estimated 1.7–2 percent of its GDP on defense (relative to the Soviet Union, which spent a punishing 12–14 percent).¹¹⁶ If competition with the United States grows, China has tremendous resources on which to draw to create more military power. Figure 12 shows how today's China and the Soviet Union (at its 1970 peak) compare across four metrics.

The Cold War also illuminates how weaker great powers compete against stronger ones. The Soviet Union, like China today, did not plan to confront the United States around the world; it had a large, regionally focused military with inferior global power-projection capabilities relative to the United States. For example, the Soviets lacked the capacity to contest the United States in either an air battle over the Mediterranean or a surface fleet battle in the Atlantic. The United States controlled the commons then, as it would later.¹¹⁷

The Soviets competed with the United States across the globe not by projecting conventional military power, but through soft power and statecraft. The Soviets encouraged the spread of communist ideology in the developing world and sought to discredit the United States and liberalism through “active measures” that shaped the information environment.¹¹⁸ These included “control of the press in foreign countries; outright and partial forgery of documents; use of rumors, insinuation, altered facts, and lies; use of international and local front organizations; clandestine operation of radio stations; exploitation of a nation's academic political, economic, and media figures as collaborators to influence policies of the nation.”¹¹⁹ Moscow supported communist leaders worldwide by providing them with economic aid and military assistance against rebels.

China's strategy today is similar.¹²⁰ Mastro argues that China rejected “the wholesale emulation of US military power” because its military goals are largely regional and because it risked backlash from the U.S. hegemon. Mastro quotes Jiang Zemin, former general secretary of the CCP, as noting that China had to “do some things but not other things, catch up in some places but not other places.” As a result, “Chinese military thinkers settled on developing capabilities to exploit US vulnerabilities … in Chinese military parlance, to ‘develop what the enemy is afraid of’ or ‘assassin's mace’ capabilities.”¹²¹ Thus, China has focused on building a powerful, regionally focused military (as well as a large and growing nuclear arsenal).

Like the Soviet Union, China competes with the United States by relying on significant nonmaterial instruments of power. China enjoys the status of a UN Security Council seat. China has exerted powerful ideological influence around the world, previously by exporting Maoism¹²² and more recently by promoting ideas about state capitalism, respect for sovereignty, and “anti-hegemonism.” In the words of China's Foreign Ministry, “The United States has developed a hegemonic playbook to stage ‘color revolutions,’ instigate regional disputes, and even directly launch wars under the guise of promoting democracy, freedom and human rights…. It has taken a selective approach to international law and rules, utilizing or discarding them as it sees fit, and has sought to impose rules that serve its own interests in the name of upholding a ‘rules-based international order.’”¹²³

Such ideas resonate in many countries, notably authoritarian ones that U.S. regime change efforts have antagonized. To spread these ideas, the CCP's United Front Work Department uses propaganda to mute criticism of China, celebrate Chinese accomplishments, and discredit the United States and its partners.¹²⁴ China also supports autocratic leaders all over the world by bringing local and central government officials to China for education programs, and by promoting “smart city” technology sales and training.¹²⁵ As the world's leader in key technologies of control, such as facial and voice recognition, China's toolkit for influencing operations and exporting authoritarianism far exceeds that of the Soviet Union.¹²⁶

In sum, scholars characterize the Soviet Union as a superpower and the Cold War as a bipolar competition. If the Soviet Union was a superpower then, China is one today. Just as China is currently weaker than the United States on some dimensions of power, so was the Soviet Union then. Yet despite gaps in its national power, the USSR absorbed the full national security energies of the United States in a four-decade-long security competition. The Cold War divided the globe into rival camps, shadowed the world in the threat of nuclear war, and fueled proxy wars that killed tens of millions of people. That was the kind of competition waged by the Soviet Union—and that is the level of competition of which China is already capable.

The bipolar distribution of power could shift for a few different reasons. I examine two arguments: (1) because of slowing growth, China will be increasingly unable to compete against the United States, and (2) the system will soon be (or is) multipolar.

China's slowing economic growth has touched off a debate about the country's future.¹²⁷ I clarify this debate and how it relates to great power competition with three points.

slowing growth? Many observers doubt China's future economic capabilities because of its slowing growth. But China's future as a great power does not depend on it sustaining high rates of growth. China's economic slowdown was both predictable and predicted. Fast-growing economies always slow down after they reach about the middle-income level; after years of high growth, annual rates will slow to about 1–2 percent.¹²⁸ Such a transition would reflect a success, not a failure, for China.¹²⁹ When debating China's future, the question is not whether China can overcome its various challenges to sustain 6 or 7 percent growth. No country at this developmental stage has ever sustained such growth and nor will China. Rather, the question is whether China will successfully settle into a sustainable range of 1–2 percent growth.

economic headwinds? Some observers are skeptical of China's future economic strength because they argue that various tailwinds that supported China's rise are shifting to disadvantageous headwinds. Demographics is one;¹³⁰ indeed, Chinese demographics have shifted in an unfavorable direction as more and more workers age out of the labor force without enough younger workers to replace them.¹³¹ Furthermore, observers warn that China's future growth will slow because of decades of heavy investment and the risk of “two severe and intertwined crises—the downward spiral in its property market and the looming risks from trillions of dollars of hidden debt accumulated by local governments.”¹³²

Such headwinds are precisely the reasons why catch-up growth invariably slows, and why Chinese growth is slowing now. Favorable demographics boosted growth in twentieth-century rising economies (e.g., Japan, South Korea, Taiwan), but as their societies aged, unfavorable demographics dampened growth. China also enjoyed a demographic “dividend,” which has shifted to a demographic “penalty” as China's society ages.¹³³ Furthermore, other rapidly rising economies—Japan, South Korea, and the United States in the nineteenth century—experienced financial crises that depressed growth. Today, those countries are among the world's richest and most technologically advanced.

the middle-income trap. A third and related argument is whether China can surmount the “middle-income trap.” Observers debate whether China's GDP per capita will reach the high-income category or will stagnate, as has happened for most high-growth economies.¹³⁴ Optimists might note that economic growth beyond middle income correlates with high levels of human capital, which China has created in abundance.¹³⁵ Pessimists note China's stagnating productivity levels (as measured by “total factor productivity”) and argue that several of Xi Jinping's policies will dampen future growth.¹³⁶ Importantly, however, income categories graft poorly onto the balance of power.

China's future as a great power does not depend on a successful transition to the high-income category. To begin with, the World Bank's GDP per capita threshold for high-income countries—$13,205 for 2023—has little connection to the GDP per capita of the world's most economically and technologically advanced countries, such as Germany ($53,970) and Japan ($39,039).¹³⁷ More importantly, as this article demonstrates, GDP per capita is a poor measurement of great power. The Soviet Union never reached the high-income level but was nonetheless a profoundly dangerous superpower competitor. To be sure, China's ability to overtake the United States would require China to raise its GDP per capita (although given that China's population is four times larger than that of the United States, China would not require parity). But China need not overtake the United States economically or militarily to engage it in a dangerous security competition.

Today one commonly hears that the international system has evolved into a “new multipolar world.”¹³⁸ Emma Ashford and Evan Cooper are undoubtedly correct when they argue that “a variety of capable, dynamic middle powers … will help to shape the international environment in coming decades.”¹³⁹ But this is a separate issue from polarity (i.e., the number of great powers). How likely is the emergence of one or more great powers?

germany and japan. Figures 10 and 11 show that the world currently has two latent powers: Germany and Japan. Both countries exceed the median great power economic capabilities (27 for GDP, 15 for composite ratio). Yet because of their grand strategic choices, they fall short of the great power thresholds for military capabilities. As figure 11 shows, the thresholds for the military metrics are 23 percent for military expenditure and 88 percent for military personnel. Japan and Germany are well below both thresholds: 5 and 7 percent, respectively, for military expenditure, and 18 and 14 percent, respectively, for military personnel.

The system might shift into multipolarity if either country chooses to mobilize greater levels of military power. But doing so would require each to dramatically depart from its prevailing grand strategy, which appears highly unlikely.¹⁴⁰ Motivated by growing regional threats, both countries have announced modest increases in defense spending.¹⁴¹ Yet Germany walked back this plan, and Japan may do so as well.¹⁴² The Japanese public opposes tax hikes to pay for increased defense spending, which may force the government to borrow in order to fulfill promised increases.¹⁴³ But with debt at 263 percent of its GDP, Japan is already the most indebted among the world's developed economies.¹⁴⁴ Even if Germany and Japan fulfilled these modest increases, both countries would remain below the great power threshold.

russia. Some observers argue that the international system is multipolar because Russia is a great power. As figures 10 and 11 show, Russia sits at the low end of the normal range for the composite metric and below the normal range for both military expenditure and military personnel (particularly the former). Thus, Russia is not a great power—a conclusion further supported by its inability to militarily defeat a non–great power (Ukraine).¹⁴⁵ Russia's power is also reduced by its dependence on natural resource exports, a human capital crisis, corruption, and other economic maladies.¹⁴⁶ Although Russian President Vladimir Putin declared that whichever country leads in AI will “become the ruler of the world,” Russia lags in the frontier technologies that will likely drive future economic growth and military power.¹⁴⁷ Still, experts caution against underestimating Russia—a warning validated by its territorial revanchism. Russia is an energy superpower; it amplifies China's “counter-hegemonic” narrative against the U.S.-led international order; it subverts the United States, other democracies, and NATO; and it bolsters authoritarian regimes.¹⁴⁸ Russia is not a great power—but it is nonetheless a regional power with significant national capabilities.

india. Observers sometimes argue that India is or will soon be a great power in a multipolar world. Although India indeed ticks many of the boxes for great power, this article shows that it currently sits outside the great power ranks.¹⁴⁹Figures 10 and 11 show that India exceeds the great power threshold on two of the four ratio metrics (GDP and military personnel). But it remains below the great power threshold for the composite and military expenditure metrics: 6 percent and 8 percent, respectively.

Optimists can point to a variety of signs that India will develop a great power economy and technological base. Its advantageous demographics create the potential for significant economic growth.¹⁵⁰ Technologically, India has gained strength on several innovation metrics (particularly related to human capital), including in frontier technologies.¹⁵¹ India has benefited from shifts in global supply chains and technology transfer from the United States, which views India as a valuable partner vis-à-vis Beijing.¹⁵² It is also important to note that in 1990, my analysis shows that China's composite score was 2 percent (see figure 5)—yet China crossed the great power threshold of 8 percent only twelve years later. Japan experienced a similar leap in its economic power in 1960–1970, when its composite score jumped from 6 to 21 percent. A lot can change in a decade.

India's rise to great power status remains contingent on several policies and reforms. Capitalizing on favorable demographics requires policies to improve infrastructure, expand the manufacturing sector, raise human capital levels, and reduce discrimination (and violence) against girls and women to increase female labor force participation.¹⁵³ India also has significant ground to cover in the military realm. Its defense spending ranks at 10 percent (see figure 11), which is far from the normal range for great power military expenditure (23–105 percent). Raising this percentage would require both continued economic growth and major changes in India's strategic thinking.¹⁵⁴ In sum, the most likely cause of a shift to multipolarity will result from the continued rise of India. Yet the country is not yet a great power, and its future economic growth and military rise are contingent on policy choices. The world is bipolar, for now.

“Let me tell you something,” President Barack Obama told Congress during his 2016 State of the Union address, “the United States of America is the most powerful nation on Earth,” he said. “Period. Period. It's not even close.” In case anyone did not get the message, Obama repeated “it's not even close” two more times, while the audience applauded.¹⁵⁵ But was it close? And how close must a country get to the United States to challenge it in a great power competition? This article contributes to such debates by creating an inductive method for comparing national power, both to validate common metrics and to establish thresholds for great power capabilities.

This method has shown, first, that thresholds for great power are far lower than many scholars assume. The balance of power is often highly uneven among great powers—even between superpowers. Countries that engaged other great powers in dangerous security competitions often had far inferior material capabilities.

Second, China is either within or well past what constitutes the historical normal range for great powers. In fact, in contrast to the argument that the United States enjoys a substantial lead, I find that China today is a superpower whose capabilities on most dimensions exceed those of the Soviet Union at its Cold War peak. Third, contrary to assertions that the world remains unipolar or has shifted into multipolarity, this article has shown that the world is bipolar. India and Russia are indeed influential regional powers, and India's continued rise may, in the medium term, shift the system into multipolarity. As of 2024, though, the system is bipolar.

The shift from a unipolar, U.S.-dominated system to a bipolar system has important implications for international politics. Engaged in a security competition with a superpower rival, China has both the motivation and the resources to shape international politics in ways that protect its interests. Indeed, Beijing already supports authoritarian leaders in a variety of ways, contributing to a global trend of democratic decline.¹⁵⁶ China's contestation of human rights and other norms is transforming multilateral institutions’ activities and agendas.¹⁵⁷ China's political and economic support has already affected the balance of power in the Russo-Ukrainian War and strengthens Iran vis-à-vis the United States and Europe.¹⁵⁸ Furthermore, China has transformed the balance of power in East Asia, which elevates the risk of war over Taiwan and creates the risk of war and nuclear escalation between China and the United States.¹⁵⁹ By threatening U.S. regional power projection, China's great power rise calls into question the credibility of U.S. security guarantees of its regional allies and threatens the alliance system at the core of current U.S. grand strategy. After 1990, the shift from bipolarity to unipolarity transformed U.S. foreign policy and international politics. Today, the shift from unipolarity to bipolarity makes another transformation likely.

The author is grateful for generous and helpful feedback from Stephen Brooks, Jeffrey Ding, Jeffrey Friedman, Yusaku Horiuchi, Jason Lyall, Michael Mastanduno, Cullen Nutt, Andrew Payne, Barry Posen, Daryl Press, Øystein Tunsjø, Benjamin Valentino, and William Wohlforth. The author also thanks the anonymous reviewers as well as students and faculty at University of Notre Dame, University of Oxford, and Texas A&M University for valuable comments.