ABSTRACT
Unipolarity poses theoretical problems for the dominant realist, particularly neorealist or structural realist, paradigm.1 There is no realist consensus on the influence of unipolarity on state behaviour.2 Neorealists expect unipolarity to be fleeting since a countervailing coalition will emerge, but none has so far in the post-Cold War, post-Soviet period since 1991. Two potential candidates, the Shanghai Cooperation Organization (SCO) promoted by China and Russia, or an enlarged European Union (EU) with an independent defence capability and unified foreign policy, cannot be counted as countervailing coalitions, nearly all the latter states being formal allies of the United States, and the enlarged EU neither having a serious independent defence capability nor a unified foreign policy. States have responded by neither balancing nor bandwagoning but by ‘adjusting in various ways to the reality of a US-centered international system’ to US dominance.3 This essay, while not being a comprehensive survey, attempts to review the main arguments in the recent literature on unipolarity in international relations theory, situating them in the context of the unfolding behaviour of the present world system’s sole pole, the United States. How, therefore, do we theorize unipolarity? Is it agreed that the United
States is a unipolar hegemon since 1991? Tentative answers are that unipolarity is military not economic, that the economic integration of the US with the rest of the world gives other powers, particularly China, some degree of countervailing power. Furthermore, it is argued that unipolarity does not necessarily imply hegemony. All historical hegemons were unipolar great powers but all unipolar great powers are not necessarily hegemons. Current US unipolarity is a case of ‘incomplete hegemony’ especially vis-à-vis the Asia-Pacific.4 George Modelski distinguishes between ‘raw power’ and institutional power.5 By the former metric the world is unipolar, but in international institutions, where most major political decisions are made in today’s increasingly complex world, power means decisional or voting power, which is not unipolar since it is decided by the voting governments, although it maybe be lopsidedly in favour of the leading power. Modelski argues that ‘monopoly power (is associated with) excessive costs combined with underperformance. Because it yields high profits but deteriorates into incompetence, a monopoly attracts competition
and generates serious conflicts.’ He, therefore, tends to agree with structural realists’ expectations in the long run. However, in terms of pure military power, all theorists, both those who believe in unipolar stability and those who do not, agree that the United States is the sole pole of the world system, although exactly how powerful it is relative to others and the extent of its power to get its way, are matters of debate. How stable is unipolarity? Is US unipolarity stable because the US is per-
ceived as a relatively benign hegemon, not bent on military conquest, even by Russia and China? And is there actually a demand for US power as a balancing force to overcome regional security dilemmas in Europe, Asia and the Middle East? Is that why there has been no countervailing coalition? The views of some leading representative critics of structural realism who take varying positions such as that unipolarity is stable, or that ‘hard-balancing’ of the unipolar hegemon not being possible second-rank powers resort to an innovation called ‘soft-balancing’, and further that such ‘soft-balancing’ is not what it seems, are presented below first, before presenting the views of leading defenders of the realist position. William Wohlforth argues that the post-1991 unipolarity is unambiguous,
peaceful and durable, the chief threat to it being the US failure to do enough, to be a hegemon on the cheap.6 His argument is that US raw-power advantage is so crushing that the system is not characterized by rivalry over leadership. The second-rank powers have no incentive to try to challenge or invite the focused enmity of the United States. Related to this, security competition among second-rank powers is also minimized. Furthermore, the US is an offshore power that is both less threatening to, and less threatened by others, whereas attempts by any of the other powers to build themselves up will trigger local balancing moves and rivalries. Hence, long-term durability can also be expected. Wohlforth cites both hegemonic stability theory and balance of power theory as predicting peace under unipolarity (that is, so long as unipolarity remains unambiguous, and prior to the emergence of a dissatisfied state which also has the capabilities to challenge the hegemon). Wohlforth tackles the more difficult and theoretically more fundamental
argument about unipolarity’s durability as follows. First, he points out that two earlier periods of what are often considered hegemony, viz., Pax Brittanica and the Cold War, were actually characterized by hegemonic rivalry, unlike post-1991 unipolarity. US raw-power superiority cannot be credibly challenged in the foreseeable future. This is one plank of his durability argument. The other plank is geography and its implications. The United States is an offshore power while all other potential poles are in or around Eurasia. This means that global counterbalancing attempts by any one or more of these will produce local rivalries which will undercut any challenger power or powers and hence, the threshold relative power needed to sustain US unipolarity is lower than generally assumed. None of the three possible processes that might end unipolarity seem to have a possibility of success, viz., counterbalancing by other powers, regional integration, or the differential growth of power.
None of these are likely to produce an entity with a defence industry and power projection capabilities that can rival the United States. Even if any such unified European (EU?), Eurasian (a new Russian empire?) or East Asian (China-led?) pole gets created, Eurasian counterbalancing will emerge, nullifying efforts to rival the United States. Even China, which because of its low base has a good chance of maintaining a high economic growth rate, will for the very reason of its relative economic and technological backwardness find it very difficult to mount a challenge even in the long run. Wohlforth sees the main threat to unipolarity as the
