Realism in International Relations

The theory of realism has had a significant influence on the study of international politics, as it appears in practice. Realism is shaped by power politics. Realist theory premises on the state as the primary actor of international relations. States operate to achieve two interrelated goals: power and security. Power increases and guarantees security, while security enables states to acquire and consolidate more power.

The realist theory of IR was shaped by thinkers who were greatly influenced by the politics of the Second World War. The realist scholarship was highly critical of the inter-war idealist school of thought, which was dubbed as “utopian” for their optimism in cooperation between nations and collective security framework. Realist scholarship emphasizes the notion that war is the natural condition for states. Carl Von Klauswitch writes, “War is politics by another means.” Hans Morganthau resonates, “Politics is a struggle for power over men.” To realists, war is undesirable but natural.


The realist theory dates to antiquity, with state behaviour & practices, conformed to self-interest and driven by power relations. Kautilya (c.375-283bc), Thucydides (c.460-406bc), Sun Tzu (c.544-496bc), Niccolò Machiavelli (1469-1527), Thomas Hobbes (1588-1679), are together considered founding fathers of political realism. Despite the different periods, these thinkers emphasized international politics as the continuous struggle for power.

The classical realist theory begins with Thucydides representation of power politics as a law of human behaviour. Writing in the context of the Greek city-state system, Thucydides in his History of the Peloponnesian War, notes that there is a certain “natural order of things” between “strong” and “weak” states. Thucydides was both an active participant, and an observer of, the Peloponnesian War, a conflict between Athens and Sparta.

The main cause for the Peloponnesian War, Thucydides noted, was “the growth of Athenian power and the fear which this caused in Sparta.” This is a classic case of how the distribution of power can shape the behaviour of the state actors. Thucydides notes that Sparta’s national interest was “survival” and the growing power of Athens meant a direct threat to its existence. He looks at human nature as the basic cause for the motivations of fear, honour, and self-interest.

Kautilya, popularly known as Chanakya, also provided for theories of statecraft, diplomacy, strategy, and power in his work Arthashastra (300bc). Unlike the realism professed in western societies, Kautilya noted that the chief objective of the state is the welfare of the people. Kautilya’s Mandala Theory provides for a six-fold policy to interact with the neighbours, which includes co-existence, neutrality, alliance, double policy, march, and war. He also provided various tactics to achieve these objectives: conciliation, gift and bribery, dissention, deceit and pretence, and war.

In Machiavelli’s realism, the need for survival requires state leaders to distance themselves from the notions of morality. He argued, these principles were harmful if adhered to by the state leaders. Machiavelli’s moral scepticism is heavily derived from his writing of Il Principe (The Prince) in the Florentine Republic. To be successful in politics, he argued, one had to act based on what human nature is, and not on what it should be. To Machiavelli, the need for survival was derived from human nature. Machiavelli provided some realist maxims: it is better to be feared than loved; a prince should act both like a lion and a fox; it is necessary to learn to not be good.

A still from the movie: Dr Strangelove, 1964

Thomas Hobbes provides realists with an interesting account of human nature in a hypothetical state-of-nature condition. Writing during the English Civil War, Hobbes provided a profound sense of man’s life in the state of nature as “solitary, poor, nasty, brutish, and short”. Hobbes argued that without the higher authority to provide security, there is always a state of war – every man against every man. Hobbes wrote, “the state of nature is the state of war.” According to Hobbes, the condition of international politics closely resembles a state of war.

These thinkers make up for the classical realist tradition, irrespective of the time they were writing them in. In their writings, we find that statism, survival and self-help make up for the realist theories. Statism is the idea that the state is the legitimate representative of the collective will of the people. The Peace of Westphalia (1648) provides the realists with the state as a unit of sovereign power in international politics. However, outside the borders of the state lies the state of anarchy, where there is no world government.

Under an anarchic international system, the survival of the state is depended on how much power it wields. States with more power have better chances of survival, and those with less power tend to lose their existence. Therefore, power is critical for realists. Self-help is a fundamental principle of state action, for there will be states acting in self-interest. According to realists, every state must ensure that their survival is their responsibility.

Twentieth-Century Classical Realism

Writing in the backdrop of the inter-war idealist optimism, E.H. Carr, a realist thinker, provides an expansive critique of the league of nations and the liberal theory of international relations. In his classic work The Twenty Years’ Crisis 1919-1939, Carr shows how liberal conceptions of rational and moral world order (utopia) needed to be replaced by an analytical approach to politics that held power at the centre (realism).

Hans J. Morgenthau was one of the most important and profound scholars of the realist theory of IR. In his seminal work Politics Among Nations, Morgenthau always emphasized that international politics is a “struggle for power”, like any other politics. And whatever be the ultimate aims of international politics, “power will always remain the immediate aim”. To Morgenthau, humans were hardwired to pursue power and they would do anything to attain and increase their own power. Like individuals, he claimed, the goal of every state was to maximize its power.

Hans Morgenthau’s Six Principles of Political Realism:

  1. Politics is governed by Objective Laws which have roots in Human Nature
  2. National Interest defined in terms of National Power
  3. Interest is always Dynamic
  4. Abstract Moral Principles cannot be applied to Politics
  5. Difference between Moral Aspirations of a Nation and the Universal Moral Principles
  6. Autonomy of the “Political”

Morgenthau identified three patterns of power among states: to attain power, to increase power, and to project their power. These three patterns, he noted, were the root cause of all of humanity’s lust for power. For realists, national interest is always defined in terms of power. And the most important interest of every other state is to sustain and survive the anarchic structure of the international system. Morgenthau, like his contemporaries, argued that national interest and universal moral principles do not go along.

Realists have, over the years, accepted balance of power as an essential element of the international system to preserving the liberty of states. Balance of power means that when a state’s survival is threatened by a hegemonic state or coalition of stronger states, it should establish a formal alliance and seek to preserve its own survival by checking the power of opposing sides. The balance of power enables an equilibrium in the international system, where no power can dominate over the other. The classic example of such a system is the cold war competition between the East and the West, as instituted in collective security of the Warsaw Pact and North Atlantic Treaty Organization (NATO).


In the 1979 work of Kenneth Waltz, Theories of International Politics, structural realism (neorealism) emerged as a theory of international relations. Writing during the cold-war period, Waltz begins with international politics as a struggle for power. Both in his Man, The State and War (1959) and Theories of International Politics (1979), Waltz provides a scientific explanation for international politics. In his 1959 work, Waltz classified the causes of war into three categories, or levels of analysis:

  1. individual level
  2. state level
  3. systemic level

The individual level, to Waltz, meant wars caused by the nature of political leaders such as state leaders, who are driven by human nature. This is consistent with classical realism. At the state level, he looks at the domestic makeup of the states – referring to Lenin’s theory of imperialism, and non-democratic structures, etc. Waltz argues that it is the systemic level, which is the anarchic nature of the international system, that causes nations to compete against one another and to war. He does not attribute the struggle for power to human nature, instead, Waltz argued that security competition, inter-state conflict, and structure of the international system.

Neorealists define the structure of the international system in terms of three elements:

  1. Organizing Principles
  2. Differentiation of Units
  3. Distribution of Capabilities

Waltz identified two organizing principles: anarchy – in the international system, and hierarchy – in the domestic political system. He also argued that the units of the international system – whether democracy or otherwise – does not matter in the functioning of sovereign states. However, to Waltz, it is the third element “distribution of capabilities” that defines the state behaviour in international politics. Neorealists argue the relative distribution of power in the international system will help in understanding war and peace, alliance politics, and the balance of power.

For instance, during the interwar period between 1919 and 1939, there existed multiple great powers, and therefore, a multipolar international system. The cold war era between 1945 and 1989 had two great powers (the USA and the USSR). And there was a balance of power. However, since the end of the cold war, there was a consensus among scholars that the international system has moved towards a unipolar structure, with the United States at the helm. But, with the American pursuit of isolationism, China’s influence on the rest of the world, and the growth of non-governmental entities and the influence they wield on the international system, the polarity question today is somewhat conflictual.

Waltz argues that states must be concerned about the capabilities of other states. To him, power was not an end, as perceived by the classical realist, but a means to an end – and the end being security. The ultimate concern for a state is not power, he writes, but security. To neorealists, states are not power maximizers, but security maximizers. This form of thinking was later known as defensive neorealism, the realism professed by Ken Waltz.

John Mearsheimer, in his work The Tragedy of Great Power Politics propounds another variant of neorealism, known as offensive neorealism, providing a different account of power dynamics that shape the international system. Mearsheimer is different from Waltz in his assessment of state behaviour, as he argues that states are power maximizers and that they understand that the best way to survive in an international anarchic system, is to be the “most powerful state in the system”. In Mearsheimer’s neorealism, states can never know the intentions of other states. Therefore, he argues, states will constantly seek to accumulate power, and that cooperation between states become difficult.  Becoming the only global hegemon in the international system is the ideal form of survival in the system.

Neoclassical Realism

Since the end of cold-war and the dissolution of the USSR in 1989, several thinkers in the neorealist scholarships have moved beyond thinking about the nature of international politics in terms of international structure, but in terms of domestic politics. They claim that it is not only important to think of politics in terms of the relative distribution of power, but also in terms of state identity, perception of state leaders, and the state-society relationships.

cold war
Presidents George Bush and Mikael Gorbachev shaking hands at the end of a press conference about the peace summit in Moscow. Peter Turnley/Corbis/VCG via Getty Images

Neoclassical realism was the term coined by Gideon Rose in his 1998 World Politics essay, which was a combination of classical realism and neorealism. To neoclassical realists, the concept of perception and misperception, intentions of other states, and domestic variables affect the decision-making in foreign policy. Some of the most prominent thinkers of neoclassical realism include Fareed Zakaria (1998), Robert Jervis (1999), Gideon Rose (1998), William Wohlforth (1993), etc.


Even though there are several variations to the realist theory of IR, there are some essential elements upon which the theory rests. These elements, as discussed earlier, in parts, are statism, survival, and self-help. Realists emphasize the fact that the state is the main and important actor in the international system. Sovereignty enables states to make and enforce laws within a particular territory, thereby making states the main actors. In the international system, realists argue, states compete for power and security. The second element, survival, unites all strands of realist theories, for they claim that the ultimate concern for all states is survival in the international system. Even though the realists disagree on whether the states are power-maximizers or security maximisers, they agree on states act in a manner they deem fit to survive in the international system. As Henry Kissinger writes, “a nation’s survival is its first and ultimate responsibility; it cannot be compromised or put to risk.” Third, self-help is again the most important aspect of the realist theory. Since there is no overarching authority over states, it becomes imperative for states to help themselves in times of crisis.