Unipolarity in international politics is a distribution of power in which one state exercises most of the cultural, economic, and military influence.
Nuno P. Monteiro, assistant professor of political science at Yale University, argues that three features are endemic to unipolar systems:
- Unipolarity is an interstate system and not an empire. Monteiro cites Robert Jervis of Columbia University to support his claim, who argues that “unipolarity implies the existence of many juridically equal non-states, something that an empire denies.” Monteiro illustrates this point further through Daniel Nexon and Thomas Wright, who state that “in empires, inter-societal divide-and-rule practices replace interstate balance-of-power dynamics.”
- Unipolarity is anarchical. Anarchy results from the incomplete power preponderance of the unipole. Columbia University's Kenneth Waltz, whom Monteiro cites, argues that a great power cannot “exert a positive control everywhere in the world.” Therefore, relatively weaker countries have the freedom to pursue policy preferences independent of the unipole. The power projection limitations of the unipole is a distinguishing characteristic between unipolar and hegemonic systems.
- Unipolar systems possess only one great power and face no competition. If a competitor emerges, the international system is no longer unipolar. Kenneth Waltz maintains that the United States is the only “pole” to possess global interests.
The post-Cold War international system is unipolar: The United States’ defense spending is “close to half of global military expenditures; a blue-water navy superior to all others combined; a chance at a splendid nuclear first strike over its erstwhile foe, Russia; a defense research and development budget that is 80 percent of the total defense expenditures of its most obvious future competitor, China; and unmatched global power-projection capabilities.”
William Wohlforth, the Daniel Webster professor of government at Dartmouth College, believes unipolarity is peaceful because it “favors the absence of war among great powers and comparatively low levels of competition for prestige or security for two reasons: the leading state’s power advantage removes the problem of hegemonic rivalry from world politics, and it reduces the salience and stakes of balance of power politics among the major states." This idea is based on hegemonic stability theory and balance of power theory. Hegemonic stability theory stipulates that “powerful states foster international orders that are stable until differential growth in power produces a dissatisfied state with the capability to challenge the dominant state for leadership. The clearer and larger the concentration of power in the leading state, the more peaceful the international order associated with it will be." Balance of power theory stipulates that as long as the international system remains unipolar, balance of power theory creates peace. “Therefore one pole is best, and security competition among the great powers should be minimal.” Unipolarity generates few incentives for security and prestige competition among great powers.
Nuno P. Monteiro argues that international relations theorists have long debated the durability of unipolarity (i.e. when it will end) but less on the relative peacefulness unipolarity brings among nations within an international system. Rather than comparing the relative peacefulness of unipolarity, multipolarity, and bipolarity, he identifies causal pathways to war that are endemic to a unipolar system. He does not question the impossibility of great power war in a unipolar world, which is a central tenet of William C. Wohlforth in his book World Out of Balance: International Relations and the Challenge of American Primacy. Instead he believes “unipolar systems provide incentives for two other types of war: those pitting the sole great power against a relatively weaker state and those exclusively involving weaker states.” Monteiro’s hypothesis is influenced by the first two decades of the post-Cold War environment, one that is defined as unipolar and rife with wars. “The United States has been at war for thirteen of the twenty-two years since the end of the Cold War. Put another way, the first two decades of unipolarity, which make up less than 10 percent to U.S. history, account for more than 25 percent of the nation’s total time at war.”
Read more about this topic: Polarity In International Relations