Полярность в международных отношениях: типы и динамика

Way in which power is distributed within the international system
Polarity in international relations is any of the various ways in which power is distributed within the international system. It describes the nature of the international system at any given period of time. One generally distinguishes three types of systems: unipolarity, bipolarity, and multipolarity for three or more centers of power. The type of system is completely dependent on the distribution of power and influence of states in a region or globally. Scholars differ as to whether bipolarity or unipolarity is likely to produce the most stable and peaceful outcomes. Kenneth Waltz and John Mearsheimer are among those who argue that bipolarity tends to generate relatively more stability. In contrast, John Ikenberry and William Wohlforth are among those arguing for the stabilizing impact of unipolarity. Some scholars, such as Karl Deutsch and J. David Singer, argued that multipolarity was the most stable structure. The Cold War period was widely understood as one of bipolarity with the US and the USSR as the world's two superpowers, whereas the end of the Cold War led to unipolarity with the US as the world's sole superpower in the 1990s and 2000s. Scholars have debated how to characterize the current international system.

Unipolarity is a condition in which one state under the condition of international anarchy enjoys a preponderance of power and faces no competitor states. According to William Wohlforth, "a unipolar system is one in which a counterbalance is impossible. When a counterbalance becomes possible, the system is not unipolar."

Numerous thinkers predicted U. S. primacy in the 20th century onwards, including William Gladstone, Michel Chevalier, Kang Youwei, Georges Vacher de Lapouge, H. G. Wells in Anticipations (1900), and William Thomas Stead. Liberal institutionalist John Ikenberry argues in a series of influential writings that the United States purposely set up an international order after the end of World War II that sustained U. S. primacy. Michael Beckley argues American primacy is vastly underestimated because power indices frequently fail to take into account GDP per capita in the U. S. relative to other purportedly powerful states, such as China and India. In 2011, Barry Posen argued that unipolarity was in wane and that the world was shifting towards multipolarity. In 2019, John Mearsheimer argued that the international system was shifting from unipolarity to multipolarity. In 2022, William Wohlforth argued that the international system was heading towards a system that can be characterized neither as bipolarity nor multipolarity. He added that polarity did not appear to matter as much in the current international system, as great powers command a far smaller share of power vis a vis the rest of the states in the international system. In 2023, Wohlforth and Stephen Brooks argued that the United States is still the unipole but that U. S. power has weakened and the nature of U. S. unipolarity has changed.

Scholars have debated the durability and peacefulness of unipolarity. William Wohlforth argues that unipolarity is durable and peaceful because it reduces the likelihood of hegemonic rivalry (because no state is powerful enough to challenge the unipole) and it reduces the salience and stakes of balance of power politics among the major states, thus reducing the likelihood that attempts at balances of power cause major war. Wohlforth builds his argument on hegemonic stability theory and a rejection of the balance of power theory. According to Carla Norrlöf, U. S. unipolarity is stable and sustainable due to a combination of three factors: 1. The status of the American dollar as the world's dominant reserve currency, 2. American commercial power, and 3. American military preponderance. The United States benefits disproportionately from its status as hegemon. Other states do not challenge U. S. hegemony because many of them benefit from the U. S. led order, and there are significant coordination problems in creating an alternative world order. Nuno P. Monteiro argues that unipolarity is conflict prone, both between the unipole and other states, and exclusively among other states. Monteiro substantiates this by remarking that "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 of U. S. history, account for more than 25 percent of the nation's total time at war." Secondly, even if the United States acts benevolently, states will still attempt to balance against it because the power asymmetry demands it: In a self help system, states do not worry about other states' intentions as they do other states' capabilities. "Unbalanced power leaves weaker states feeling uneasy and gives them reason to strengthen their positions," Waltz says. In a 2021 study, Yuan kang Wang argues from the experience of Ming China (1368–1644) and Qing China (1644–1912) that the durability of unipolarity is contingent on the ability of the unipole to sustain its power advantage and for potential challengers to increase their power without provoking a military reaction from the unipole.

Bipolarity is a distribution of power in which two states have a preponderance of power. In bipolarity, spheres of influence and alliance systems have frequently developed around each pole. For example, in the Cold War of 1947–1991, most Western and capitalist states would fall under the influence of the US, while most Communist states would fall under the influence of the USSR. According to Wohlforth and Brooks, "the world was undeniably bipolar" during the Cold War. Dale Copeland has challenged Waltz on this, arguing that bipolarity creates a risk for war when a power asymmetry or divergence happens.

Multipolarity is a distribution of power in which more than two states have similar amounts of power. The Concert of Europe, a period from after the Napoleonic Wars to the Crimean War, was an example of peaceful multipolarity (the great powers of Europe assembled regularly to discuss international and domestic issues), as was the Interwar period. Examples of wartime multipolarity include World War I, World War II, the Thirty Years War, the Warring States period, the Three Kingdoms period and the tripartite division between Song dynasty/Liao dynasty/Jin dynasty/Yuan dynasty.

Classical realist theorists, such as Hans Morgenthau and E. H. Carr, hold that multipolar systems are more stable than bipolar systems, as great powers can gain power through alliances and petty wars that do not directly challenge other powers; in bipolar systems, classical realists argue, this is not possible. Neorealists hold that multipolar systems are particularly unstable and conflict prone, as there is greater complexity in managing alliance systems, and a greater chance of misjudging the intentions of other states. Thomas Christensen and Jack Snyder argue that multipolarity tends towards instability and conflict escalation due to "chain ganging" (allies get drawn into unwise wars provoked by alliance partners) and "buck passing" (states which do not experience an immediate proximate threat do not balance against the threatening power in the hope that others carry the cost of balancing against the threat). John Mearsheimer also argues that buck passing is more common in multipolar systems. Multipolarity does not guarantee multilateralism and can pose a challenge against multilateralism. According to Kemal Derviş, a decline in unipolarity creates a crisis in multilateralism; it is possible to revive multilateralism in a multipolar system, but this is more threatened and the structure to do so is not fully developed. Additionally, as multipolar systems can tend to regional hegemonies or bounded orders, agreements are formed within these bounded orders rather than globally. Though, Mearsheimer predicts the persistence of a thin international order within multipolarity, which constitutes some multilateral agreements.