Realism (international relations)
Realism is one of the dominant schools of thought in international relations theory, theoretically formalising the Realpolitik statesmanship of early modern Europe. Although a highly diverse body of thought, it is unified by the belief that world politics is always and necessarily a field of conflict among actors pursuing wealth and power. The theories of realism are contrasted by the cooperative ideals of liberalism in international relations. Realists are divided into three classes based on their view of the essential causes of interstate conflict. Classical realists believe it follows from human nature; neorealists attribute it to the  dynamics of the anarchic state system; neoclassical realists believe it results from both, in combination with domestic politics. Neorealists are also divided between defensive and offensive realism. Realists trace the history of their ideas back through classical antiquity, beginning with Thucydides. Realism entails a spectrum of ideas, which tend to revolve around several central propositions, such as: Realism is often associated with realpolitik, as both deal with the pursuit, possession, and application of power. Realpolitik, however, is an older prescriptive guideline limited to policy-making, while realism is a wider theoretical and methodological paradigm to describe, explain, and predict events  in international relations. As an academic pursuit, realism is not necessarily tied to ideology; it does not favor any particular moral philosophy, nor does it consider ideology to be a major factor in the behavior of nations. However, realists are generally critical of liberal foreign policy. Priorities of realists have been described as Machiavellian, single-mindedly seeking the power of one's own nation over others, although realists also advocated the idea that powerful nations concede spheres of influence to other powerful nations. Common assumptions. The four propositions of realism are as follows. Realists think that mankind is not inherently  benevolent but rather self-centered and competitive. This perspective, which is shared by theorists such as Thomas Hobbes, views human nature as egocentric (not necessarily selfish) and conflictual unless there exist conditions under which humans may coexist. It is also disposed of the notion that an individual's intuitive nature is made up of anarchy. In regards to self-interest, these individuals are self-reliant and are motivated in seeking more power. They are also believed to be fearful. This view contrasts with the approach of liberalism to international relations. The state emphasises an interest in accumulating power to ensure  security in an anarchic world. Power is a concept primarily thought of in terms of material resources necessary to induce harm or coerce other states (to fight and win wars). The use of power places an emphasis on coercive tactics being acceptable to either accomplish something in the national interest or avoid something inimical to the national interest. The state is the most important actor under realism. It is unitary and autonomous because it speaks and acts with one voice. The power of the state is understood in terms of its military capabilities. A key concept under realism is the  international distribution of power referred to as system polarity. Polarity refers to the number of blocs of states that exert power in an international system. A multipolar system is composed of three or more blocs, a bipolar system is composed of two blocs, and a unipolar system is dominated by a single power or hegemon. Under unipolarity realism predicts that states will band together to oppose the hegemon and restore a balance of power. Although all states seek hegemony under realism as the only way to ensure their own security, other states in the system are incentivised to prevent the  emergence of a hegemon through balancing. States employ the rational model of decision making by obtaining and acting upon complete and accurate information. The state is sovereign and guided by a national interest defined in terms of power. Since the only constraint of the international system is anarchy, there is no international authority and states are left to their own devices to ensure their own security. Realists believe that sovereign states are the principal actors in the international system. International institutions, non-governmental organizations, multinational corporations, individuals and other sub-state or trans-state actors are viewed as having little  independent influence. States are inherently aggressive (offensive realism) and obsessed with security (defensive realism). Territorial expansion is only constrained by opposing powers. This aggressive build-up, however, leads to a security dilemma whereby increasing one's security may bring along even greater instability as an opposing power builds up its own arms in response (an arms race). Thus, security becomes a zero-sum game where only relative gains can be made. Realists believe that there are no universal principles with which all states may guide their actions. Instead, a state must always be aware of the actions of the states  around it and must use a pragmatic approach to resolve problems as they arise. A lack of certainty regarding intentions prompts mistrust and competition between states. Rather than assume that states are the central actors, some realists, such as William Wohlforth and Randall Schweller refer instead to "groups" as the key actors of interest. Finally, states are sometimes described as "billiard balls" or "black boxes". This analogy is meant to underscore the secondary importance of internal state dynamics and decisionmaking in realist models, in stark contrast to bureaucratic or individual-level theories of international relations. Realism in statecraft. The ideas  behind George F. Kennan's work as a diplomat and diplomatic historian remain relevant to the debate over American foreign policy, which since the 19th century has been characterized by a shift from the Founding Fathers' realist school to the idealistic or Wilsonian school of international relations. In the realist tradition, security is based on the principle of a balance of power and the reliance on morality as the sole determining factor in statecraft is considered impractical. According to the Wilsonian approach, on the other hand, the spread of democracy abroad as a foreign policy is key and morals are  universally valid. During the Presidency of Bill Clinton, American diplomacy reflected the Wilsonian school to such a degree that those in favor of the realist approach likened Clinton's policies to social work. Some argue that in Kennan's view of American diplomacy, based on the realist approach, such apparent moralism without regard to the realities of power and the national interest is self-defeating and may lead to the erosion of power, to America's detriment. Others argue that Kennan, a proponent of the Marshall Plan (which gave out bountiful American aid to post-WW2 countries), might agree that  Clinton's aid functioned strategically to secure international leverage: a diplomatic maneuver well within the bounds of political realism as described by Hedley Bull. Realists often hold that statesmen tend towards realism whereas realism is deeply unpopular among the public. When statesmen take actions that divert from realist policies, academic realists often argue that this is due to distortions that stem from domestic politics. However, some research suggests that realist policies are actually popular among the public whereas elites are more beholden to liberal ideas. Abrahamsen suggested that realpolitik for middle powers can include supporting idealism and liberal internationalism. Historical  branches and antecedents. Historian Jean Bethke Elshtain traces the historiography of realism: While realism as a formal discipline in international relations did not arrive until World War II, its primary assumptions have been expressed in earlier writings. Modern realism began as a serious field of research in the United States during and after World War II. This evolution was partly fueled by European war migrants like Hans Morgenthau, whose work "Politics Among Nations" is considered a seminal development in the rise of modern realism. Other influential figures were George F. Kennan (known for his work on containment), Nicholas Spykman (known  for his work on geostrategy and containment), Herman Kahn (known for his work on nuclear strategy) and E. H. Carr. Classical realism. Classical realism states that it is fundamentally the nature of humans that pushes states and individuals to act in a way that places interests over ideologies. Classical realism is an ideology defined as the view that the "drive for power and the will to dominate [that are] held to be fundamental aspects of human nature". Prominent classical realists: Liberal realism or the English school or rationalism. The English school holds that the international system, while anarchical in structure , forms a "society of states" where common norms and interests allow for more order and stability than that which may be expected in a strict realist view. Prominent English School writer Hedley Bull's 1977 classic, "The Anarchical Society", is a key statement of this position. Prominent liberal realists: Neorealism or structural realism. Neorealism derives from classical realism except that instead of human nature, its focus is predominantly on the anarchic structure of the international system. States are primary actors because there is no political monopoly on force existing above any sovereign. While states remain the principal actors, greater attention  is given to the forces above and below the states through levels of analysis or structure and agency debate. The international system is seen as a structure acting on the state with individuals below the level of the state acting as agency on the state as a whole. While neorealism shares a focus on the international system with the English school, neorealism differs in the emphasis it places on the permanence of conflict. To ensure state security, states must be on constant preparation for conflict through economic and military build-up. Prominent neorealists: Neoclassical realism. Neoclassical realism can be seen  as the third generation of realism, coming after the classical authors of the first wave (Thucydides, Niccolò Machiavelli, Thomas Hobbes) and the neorealists (especially Kenneth Waltz). Its designation of "neoclassical", then, has a double meaning: Gideon Rose is responsible for coining the term in a book review he wrote. The primary motivation underlying the development of neoclassical realism was the fact that neorealism was only useful to explain political outcomes (classified as being theories of international politics), but had nothing to offer about particular states' behavior (or theories of foreign policy). The basic approach, then, was for these authors to  refine, not refute, Kenneth Waltz, by adding domestic intervening variables between systemic incentives and a state's foreign policy decision. Thus, the basic theoretical architecture of neoclassical realism is: While neoclassical realism has only been used for theories of foreign policy so far, Randall Schweller notes that it could be useful to explain certain types of political outcomes as well. Neoclassical realism is particularly appealing from a research standpoint because it still retains a lot of the theoretical rigor that Waltz has brought to realism, but at the same time can easily incorporate a content-rich analysis, since its main  method for testing theories is the process-tracing of case studies. Prominent neoclassical realists: Realist constructivism. Some see a complementarity between realism and constructivism. Samuel Barkin, for instance, holds that "realist constructivism" can fruitfully "study the relationship between normative structures, the carriers of political morality, and uses of power" in ways that existing approaches do not. Similarly, Jennifer Sterling-Folker has argued that theoretical synthesis helps explanations of international monetary policy by combining realism's emphasis of an anarchic system with constructivism's insights regarding important factors from the domestic level. Scholars such as Oded Löwenheim and Ned Lebow have  also been associated with realist constructivism. Criticisms. Democratic peace. Democratic peace theory advocates also that realism is not applicable to democratic states' relations with each another as their studies claim that such states do not go to war with one another. However, realists and proponents of other schools have critiqued both this claim and the studies which appear to support it, claiming that its definitions of "war" and "democracy" must be tweaked in order to achieve the desired result. Furthermore, a realist government may not consider it in its interest to start a war for little gain, so realism does  not necessarily mean constant battles. Hegemonic peace and conflict. Robert Gilpin developed the theory of hegemonic stability theory within the realist framework, but limited it to the economic field. Niall Ferguson remarked that the theory has offered insights into the way that economic power works, but neglected the military and cultural aspects of power. Liberal scholars Ikenberry and Deudney state that the Iraq War, conventionally blamed on liberal internationalism by realists, actually originates more closely from hegemonic realism The "instigators of the war", they suggest, were hegemonic realists. Where liberal internationalists reluctantly supported the war, they followed arguments linked to  interdependence realism relating to arms control. The realist scholar John Mearsheimer states that "One might think..." events including the Bush Doctrine are "evidence of untethered realism that unipolarity made possible," but disagrees and contends that various interventions are caused by a belief that a liberal international order can transcend power politics. Inconsistent with non-European politics. Scholars have argued that realist theories, in particular realist conceptions of anarchy and balances of power, have not characterized the international systems of East Asia and Africa (before, during and after colonization). State-centrism. Scholars have criticized realist theories of international relations for assuming  that states are fixed and unitary units. Appeasement. In the mid-20th century, realism was seen as discredited in the United Kingdom due to its association with appeasement in the 1930s. It re-emerged slowly during the Cold War. Scholar Aaron McKeil pointed to major illiberal tendencies within realism that, aiming for a sense of "restraint" against liberal interventionism, would lead to more proxy wars, and fail to offer institutions and norms for mitigating great power conflict.