The Balance of Power in a Unipolar World

Discussing how China cannot rise peacefully, John J. Mearsheimer notes1

[T]he ideal situation for any great power is to be the hegemon in the system, because its survival then would almost be guaranteed. A hegemon is a country that is so powerful that it dominates all the other states. In other words, no other state has the military wherewithal to put up a serious fight against it. In essence, a hegemon is the only great power in the system.

When people talk about hegemony these days, they are usually referring to the United States, which they describe as a global hegemon. I do not like this terminology, however, because it is virtually impossible for any state – including the United States – to achieve global hegemony. The main obstacle to world domination is the difficulty of projecting power over huge distances, especially across enormous bodies of water like the Atlantic and Pacific Oceans.

The best outcome that a great power can hope for is to achieve regional hegemony, and possibly control another region that is close by and easily accessible over land. The United States, which dominates the Western Hemisphere, is the only regional hegemon in modern history. Five other great powers have tried to dominate their region – Napoleonic France, Imperial Germany, Imperial Japan, Nazi Germany, and the Soviet Union – but none have succeeded.

I have often described the structure of the international system since 1990 as unipolar, and routinely refer to the United States as a ‘global hegemon’. Lately, I have begun to appreciate the limited usefulness of these labels. It is not that I think that these labels are not valid. The United States is vastly stronger than any other state with a “decisive preponderance in all the underlying components of power: economic, military, technological, and geopolitical”, with the result that no major power “is in a position to follow any policy that depends for its success on prevailing against the United States is a war or an extended rivalry.”2 Ikenberry, Mastanduno, and Wohlforth point out in a special issue of World Politics on unipolarity,3

While other powers can contest US forces operating in or very near their homelands, especially over issues that involve credible nuclear deterrence, the United States is and will long remain the only state capable of projecting major military power globally. This dominant position is enabled by what Barry Posen calls “command of the commons” – that is, unassailable military dominance over the sea, air, and space. The result is an international system that contains only one state with the capability to organize major politico-military action anywhere in the system. No other state or even combination of states is capable of mounting and deploying a major expeditionary force outside its own region, except with the assistance of the United States.

Indeed, discounting nuclear weapons for the sake of argument, all other powers combined do not have the wherewithal in terms of conventional military power to conquer the United States. The primary reason is the security provided by the Atlantic and the Pacific oceans, but not far behind is the vastly superior military apparatus of the unipole. Furthermore, the existence of thousands of nuclear warheads in the US arsenal imply that it would be suicidal for another power to attack the United States. Thus, the US is maximally secure in the precise sense that – short of eliminating all other major powers – it is hard to imagine what would make the US more secure. However, US primacy does not mean that the US can get its way on every issue or always impose its will on other major powers. Unlike regions without major powers where the US can act essentially unilaterally – Central America and the Persian Gulf immediately spring to mind – the US cannot intervene at will in regions that contain other major powers.

Neorealism defines polarity to simply be the number of great powers in the system. Virtually every realist agrees on the definition of great powers: a state is a great power in the international arena if it can put up a fight with the strongest power of the system. The problem is two-fold. On the one hand, even medium-sized powers with a second-strike capability cannot be conquered outright by the strongest power of the system. In this sense, even Britain and France can ‘put up a fight’ with the US.4 On the other hand, the question of whether or not a major power can put up a fight with the strongest power depends on the region one is taking about. Since power travels weakly over distance, the balance of power is a regional phenomena.

The problem essentially boils to the fact that it is very hard, even for the strongest state in the international system, to project power very far from home, especially far from the world ocean. This is subtly distinct from Mearsheimer’s point, which is that – since the balance of power is determined primarily by land-based military power, and the ‘stopping power of water’ is such that it is impossible to carry out a sea-borne invasion of a territory well-defended by another great power – the Atlantic and the Pacific limit to a considerable degree how much power the US can bring to bear around the globe. My point is different. The capacity of the US state to project is limited by the availability of military bases close enough to the region in question, and the viability of projecting sea-based military power. The United States can project a lot of power as far as its fighters and bombers can go, but no further.

Despite the vastly superior military of the United States, other major powers can sometimes bring more military pressure to bear on specific regions. To take an extremal example, consider Nepal. This country is bounded on one side by the impenetrable barrier of the Himalayas, and otherwise completely surrounded by Indian territory. Suppose India invades and annexes the kingdom, to howls of protest from Western leaders. The US can put a lot of diplomatic pressure on India, but that is the limit of what it can do. There is virtually no way for the US to bring any hard power to bear in this remote region. Nepal is, and will remain, strictly in the Indian sphere of influence.

This is also true in the Caucasus, which is land-locked, bounded by Russia to the north, the Black Sea to the west, Turkey to the southwest, Iran to the southeast, and the Caspian Sea to the east. This is basically Russia’s backyard, and without a much more significant decline in Russian military power, there is no way that the United States can displace it as the regional hegemon. It may not be able to challenge the US far from home, but closer to home, in its ‘near abroad’, where Russia’s security interest trump whatever inducement the Boss may offer for cooperation, Russia will try strenuously to maintain its preponderance.5

When Russia intervened in South Ossetia in 2008 despite Western opprobrium, there wasn’t much the US could do about it. This, despite the existence of a large NATO military base in Turkey. US-Russian relations reached a post-Cold War low, but Russia’s muscular intervention in the Caucasus ensured that Abkhazia and South Ossetia would never return to full Georgian control, and re-established Russia as the regional hegemon. This is not what a system with only one great power looks like.

Russia is still a military giant with a huge arsenal of nuclear weapons. It spends around $50 billion on its military which has nearly a million active-duty soldiers, three hundred ICBMs, six thousand bomber aircraft, a dozen nuclear powered submarines, thirteen hundred modern tanks, nearly five thousand armored vehicles, a thousand advanced fighter jets, a thousand military helicopters, and thirty intelligence satellites. It’s formidable land-based military is comparable to China, perhaps still exceeding it in overall capabilities due to the inexperience of the latter. In short, Russia is still a great power.6

Military force shapes world politics like a gravitational field. In every international negotiation, it is always in the background. The threat of the use of force cannot be eliminated, which is why it is most useful when it is left implicit. One should perhaps picture the unipolar system as a Ptolemaic system with the unipole as the sun, and the other great powers as the major planets with lots of moons orbiting around them. In this analogy, Russia would be Jupiter, and its moons would be the states in the Caucasus, Central Asia, and the buffer states on the west: Ukraine, Belarus, and the Baltic States.

The point is that there are other major powers in the system that matter in the calculus of the balance of power. Even regional powers can in certain places trump the superpower. South Africa can dictate terms in its neighborhood. It would require a considerable investment in terms of local power projection capabilities for the US to counter South Africa in southern Africa. South Africa is effectively the regional hegemon. The US does not have the wherewithal to displace all regional hegemons on the globe, and southern Africa is perhaps at the bottom of the list. This is why, despite US’ vastly superior military apparatus, it is not a global military hegemon.

There is, however, a critical difference between major powers and regional powers. The latter cannot put up a fight with the superpower anywhere. In as much as major powers choose not to intervene in a region, regional powers can exercise considerable influence in their neighborhoods. This is essentially what is going on in the Syrian conflict.

The Endgame in Syria

Due to Obama’s hands off approach, regional powers have become decisive in the proxy war. Iran has sent its elite Quds force to train Assad’s militia, the brutal shahiba. Armored units of Iran’s Revolutionary Guard fought alongside two thousand Hezbollah fighters and the Syrian military in the battle of Qusayr, that has marked a turning point in the conflict. Assad’s position has strengthened considerably. The baseline scenario is no longer the imminent fall of the Assad regime.

Russia has ratcheted up its supply of munitions to Assad. It plans to send S-300 missiles, that Israel has promised to destroy upon arrival. Israel has already carried out multiple strikes targeted at arsenals of missiles and anti-aircraft weapons intended for Hezbollah. Saudi Arabia, Qatar, and Turkey have been supplying weapons and ammunition to the Sunni rebels. Qatar’s supply is going mostly to zealous salafi groups. Britain and France have decided to supply weapons to moderate rebels. Even the United States is finally coming around. Secretary of State Kerry is now pushing for increasing the aid to moderate rebels, including light weapons.

The endgame in Syria hinges, first of all, on whether or not the US decides to intervene. If the Obama administration finally decides that the United States has an interest in Assad’s ouster, it would trump everything the regional players can come up with. That the survival of the Assad regime is antithetical to US interests is becoming increasingly obvious. If Iran and Hezbollah succeed in Syria, it would finally create the long-heralded Shi’a crescent – the arc of Shi’a power stretching across the breadth of the Middle East, led by Iran and including Iraq, Syria, and Hezbollah – adversely affecting the security of Israel and US’ Sunni clients. There is no point in pretending that this is now anything but an all-out sectarian war.

If Obama nevertheless decides to sit this one out, there are three ways the endgame could play out: Assad manages to prevail more or less decisively, Assad gets kicked out and replaced by a Sunni majoritarian regime, the Syrian state essentially breaks up and a protracted decade-long sectarian conflict ensues. Whichever obtains, there is virtually no possibility of stability: Syria is now a mini-security complex like Afghanistan or Lebanon, and will continue to see considerable violence for a decade or more.

If the West does not intervene decisively, the probability of a tolerable outcome is zero. On the one hand, lots of bad guys are busy chopping each others’ heads off, which is not so bad if you think about it. On the other, this hardly means that both, or either, of these awful actors will be eliminated. Either Shi’a zealots, or salafi extremists, or both are going to emerge much more powerful from this mess. Nicely done, Mr. President.

Neorealism and Geopolitical Realism

Given the regional character of the balance of military power, perhaps it is better to think of the current system as ‘uni-multipolar’, as Samuel P. Huntington prefers, although its quite a mouthful. His point is quite nuanced:7

The settlement of key international issues requires action by the single superpower but always with some combination of other major states; the single superpower can, however, veto action on key issues by combinations of other states. The United States, of course, is the sole state with preeminence in every domain of power – economic, military, diplomatic, ideological, technological, and cultural – with the reach and capabilities to promote its interests in virtually every part of the world. At a second level are major regional powers that are preeminent in areas of the world without being able to extend their interests and capabilities as globally as the United States. They include the German-French condominium in Europe, Russia in Eurasia, China and potentially Japan in East Asia, India in South Asia, Iran in Southwest Asia, Brazil in Latin America, and South Africa and Nigeria in Africa.

Wohlforth would argue that all this is just moving the goal post, and that by virtually any standard ever employed to judge the polarity of previous system structures, the current structure is unambiguously unipolar. According to neorealism this is uncontestable. However, before we can apply the neorealist model to world affairs we shall find it useful, as a first step, to introduce the map. Placing the world’s major powers in the right geopolitical framework immediately resolves the tension. That is, as one moves from neorealism to geopolitical realism à la Spykman, the appropriate description of structure of the early 21st century international system shifts from Wohlforth’s to that of Mearsheimer and Huntington.

Once one has fully grasped this distinction, one can begin to get a real handle on world affairs. There is still quite a way to go. Two necessary steps are still missing before we can do business. First, one needs to unpack hard power. On the one hand, the balance of power is determined regionally by land-based military power. On the other, the maritime realm is a natural monopoly, with the naval hegemon presiding over the centered world economy. Second, in a unipolar system, the foreign policy of the unipole is the dominant variable in world affairs. One, therefore, needs an accurate model of the political economy of the unipole. For the United States, the investment theory of party competition is the right place to get started.

Then, we can talk shop.

1 Mearsheimer, John J. “The Gathering Storm: China’s challenge to US power in Asia”. Chinese Journal of International Politics (2010) 3 (4): 381-396.

2 Wohlforth, William C. “The Stability of a Unipolar World.” International Security 24, no. 1 (1999): 5-41. Print.

3 G. John Ikenberry and Michael Mastanduno and William C. Wohlforth. “Introduction: Unipolarity, State Behavior, and Systemic Consequences.” World Politics 61, no. 1 (2009): 1-27. Print.

4 Unless the United States enjoys nuclear primacy. See Lieber, Keir A., and Daryl G. Press. “The Rise of U.S. Nuclear Primacy.” Foreign Affairs. March 1, 2006. However, it is hard to imagine a scenario where the US would even consider launching a disarming first-strike against a major power that poses no threat to the US homeland. Moreover, a missile defense system can easily be overcome by a barrage of fake warheads, usually balloons, that TMD systems cannot distinguish from the ones with the nuclear payloads. See Butt, Yousaf. “Debunking the Missile-Defense Myth.” The National Interest. Web. 21 May 2013.

5 Russia will also be operating on interior lines of supply. This factor considerably enhances the local power projection capabilities of other major powers in their immediate neighborhood. It means, for instance, that the United States will find it impossible to block access to the region. The situation is reversed far from home, where US’ ‘command of the commons’ provides it a veto over overseas power projection by other major powers.

6 An interesting question is whether Russia will band-wagon with China once the latter becomes too strong for it to handle. China will probably become preponderant in Central Asia and threaten Siberia. Russia could seek an alliance with the United States to counter China, but this won’t be very useful because the US will not be able to protect Russia from China in Central Asia, Mongolia, and Siberia. Further, China will be the biggest market for Russian energy. The most likely outcome is Russian neutrality or even tilt towards China. In other words, Russia will, and ought to, band-wagon with China when the world becomes bipolar or multipolar.

7 Huntington, Samuel P. “The Lonely Superpower.” Foreign Affairs. March 1, 1999.


3 thoughts on “The Balance of Power in a Unipolar World

  1. I would be interested to , as some has suggested hear opinions of the US weakening itself though debt and would this be a slow death of an empire. or could the us bounce back from near death because of the size of it’s economy ?
    Enjoyed your article.

    1. I’m skeptical of such arguments. The US spends a very affordable portion of its GDP on defense. It could probably sustain a rate twice as high; as it in fact did for much of the Cold War. The level of the public debt itself is quite tame. The United States could probably sustain much higher levels. Recall that Britain paid off the enormous debt of the Napoleonic wars slowly through the nineteenth century on a much smaller tax base. If the United States suffers internal decline, it would not be because of debt but because of a prolonged slowdown. That also seems quite unlikely. Witness the great strides in Silicon Valley, biotech, shale and advanced manufacturing. Of course, this doesn’t mean that most Americans will not do worse. Just that US power on the world stage is unlikely to decline dramatically for quite some time to come.

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