Classical Realism in International Relations

An ancient map of the world with a compass. Image by Ylanite Koppens.

Realism, also known as Classical Realism, is a theory that emphasizes the constant potential for competitiveness and conflict in international relations. It is based on the ideas of authors like Thucydides, Machiavelli and Hobbes, who shared a pessimistic view of human nature and politics. Realist thought emerged in the interwar period as a reaction to the supposed failures of Liberalism, which was incapable of preventing the outbreak of World War I. Scholars such as Edward Carr and Hans Morgenthau adopted an inductive methodology, because they observed the behaviors of individual states in order to posit generalized ideas about international relations. According to them, states are the main actors within an anarchic international system, and they constantly struggle for power in order to ensure their survival. During the Cold War, Classical Realism evolved into Neorealism, which gained much prominence. Today, however, Realism is just one of various international relations theories.

Precursors of Realism

The origins of Realism in International Relations can be traced back to the 5th century B.C., when Thucydides, a Greek historian and general, wrote The History of the Peloponnesian War. This book chronicles the conflict between the Peloponnesian League (led by Sparta) and the Delian League (led by Athens), from 431 to 404 B.C. Although Thucydides’ work is not explicitly an international relations theory, it encapsulates key theoretical concepts that have been extrapolated by scholars over the centuries:

Human nature: According to the Athenians, human beings are egoistic and are not bound to moral or ethical considerations about what is right or fair. Instead, they act primarily out of self-interest, in the pursuit of self-aggrandizement.
Survival of the strongest: In the Melian Dialogue, the Athenians declare that in the absence of a common authority to enforce justice internationally, power dictates the outcomes of international interactions, thus only the strong and powerful can survive.
Balance of power: Thucydides attributes the underlying cause of the Peloponnesian War to the shifting balance of power between Athens and Sparta. He argues that Sparta’s fear of the growing power of Athens propelled them into conflict. This scenario was later termed the “Thucydides Trap” by modern scholars, who highlight the potential for conflict when a rising power challenges an established one.
Disputes between realists and liberals: In the Melian Dialogue, the Athenians confront the Melians with a stark choice: submit or be destroyed. The Athenians, embodying realist principles, urge the Melians to recognize the harsh realities of power politics. The Melians, on the other hand, argue from an idealist standpoint, emphasizing principles of justice, fairness, and mutual obligations among states. They hope to win the war based on these principles, but their idealism is ultimately crushed by the unyielding logic of Athenian power, leading to their destruction.

While Thucydides’ narrative often aligns with realist principles, it is crucial to differentiate between the views of his characters and his own perspective. His understanding of power and ethics in international relations is more nuanced than the compelling arguments of the Athenians in the Melian Dialogue.

Another author that influenced Realism was Niccolò Machiavelli, a philosopher from Florence, Italy, who challenged the idea that politics should be virtuous and that ethical standards should govern warfare and state behavior. In his groundbreaking book The Prince, published in 1532, he separated politics from ethics, arguing that classical Western political thought was unrealistic because it aimed too high. Instead of focusing on what life ought to be, Machiavelli concentrated on what life is — that is, the practical realities of political life.

Central to Machiavelli’s philosophy is the concept of virtù, which differs significantly from the classical notion of virtue. For Machiavelli, virtù encompassed qualities such as ability, vigor, and the capacity to achieve one’s goals, rather than moral virtues like justice or self-restraint. He advocated for a pragmatic approach to politics, which led him to endorse actions that were effective, even if they were morally questionable. Machiavelli’s ideas gave rise to an ideology that asserts that ethics are irrelevant in politics and that any means — moral or immoral — are justified if they achieve political ends. In practical terms, he advised princes to use whatever means necessary to ensure the survival of their states — otherwise, they would lose all their relevance.

In the sixteenth century, Cardinal Richelieu, a minister of King Louis XIII of France, drew on Machiavellian ideas to create the concept of “raison d’état”. It posited that the interests of a state were necessary for its survival, and, because of that, they should prevail over individual interests. Although France was a Catholic monarchy, the main concern of the country at the time was to contain the power of the Habsburg dynasty, a rival in European power politics. As such, Richelieu put his religious allegiances aside and made alliances with Protestant states like England and the Dutch Republic to defeat the Habsburgs.

In the seventeenth century, the English philosopher Thomas Hobbes published Leviathan, a book that fundamentally challenged classical and scholastic traditions. He depicted humans as individualistic and driven by a desire for glory and a “perpetual and restless desire of power after power” that ceases only in death. According to him, humans fear dying and live in an anarchic state of nature, in which there are no constraints on human behavior. In such a scenario, humans have every incentive to engage in violent behavior — in other words, to remain in a state of perpetual war in which “every man is against every man”:

They must compete for scarce resources.
They must engage in preemptive actions to ensure their own safety.
They must dominate others to increase their own chances of survival.

According to Hobbes, individuals eventually want to escape the state of nature, and they do so by subjecting themselves to a sovereign — a state. States thus are formed by a social contract in which individuals agree to limit their freedom, in order to increase the prospects of their survival.

Key Assumptions of Realism

According to realists, states are the central elements of the international system. These are sovereign and rational entities that, following the theory of sociologist Max Weber, have a monopoly on the legitimate use of force against their citizens. In realist thought, states are seen as a “black box” or a “billiard ball”: their internal components act in unison, react to external forces, and, consequently, collide with one another. The implication of this assumption is that domestic decision-making processes are considered irrelevant to international relations.

Realists believe that the international system is anarchic — meaning that there is no entity placed hierarchically above states. Just like in the Hobbesian state of nature, states are seen as constantly fighting for their survival, in so-called “zero-sum” or “win-lose” games, in which the national interests of a country can only be secured at the expense of other countries. Because of that, realists posit that the states have to act on their own, for they cannot rely on others to ensure their own safety (an idea known as “self-help”). Yet it should be noted that some authors, such as Robert Jervis, disagree with the notion that cooperation among states is impossible. An alternative view is that cooperation is possible, but contingent upon power politics and the security interests of states.

Realism distinguishes between high politics and low politics:

High politics: Matters that are vital to the very survival of the state, namely national and international security concerns.
Low politics: All other matters, particularly economic, cultural or social affairs.

In general, realists believe that war is a valid instrument of both high and low politics, and that it can be waged for material and immaterial purposes, such as prestige. In the words of Carl von Clausewitz, a Prussian general who died long before the birth of Realism, “war is the continuation of policy with other means”.

Carr’s critique of utopianism

Edward Hallett Carr (E. H. Carr) was the founder of the realist tradition within International Relations with the publication, in July 1939, of The Twenty Years’ Crisis: 1919-1939. The title of the book is a reference to the interwar period and to the inability of appeasing Hitler and dissuading him from resorting to war.

Carr believed that states were the only relevant actors within the international system, and that their international action was motivated by power struggles. He thought international institutions were always secondary to national interests, because the main concern of states is to survive in the world.

He presented a formidable critique of the liberal approach to International Relations, which he termed “utopianism”. This perspective views war as an aberration and values like peace, social justice, prosperity, and international order as universal goods, as a universal moral. On the other hand, Carr believed that “morality can only be relative, not universal”. His argument was rooted in the observation that politicians often use the language of justice to disguise their own country’s interests or to vilify other nations to justify acts of aggression. This, he argued, demonstrated that moral ideas are derived from actual policies, contrary to the idealist belief that policies are based on universal norms.

Carr saw liberal values as simply those that are upheld by powers satisfied with the status quo. These powers preach peace to maintain their security and predominance, while unsatisfied powers see the same arrangements as unjust and prepare for war. In order to achieve peace, Carr argued that it was necessary to make concessions to unsatisfied powers, to make the international order tolerable for them. For example, he often referred to Nazi Germany as a country like any other, which cannot be appeased simply by principles and institutions. Yet he proposed territorial concessions to the Germans as a way to avoid a Second World War — something that history has proved to have been futile.

Similarly, Carr was harshly critical of the notion of free trade, because, according to him, it favored the countries that had already achieved a high level of development. He believed developing countries had every right to engage in protectionist policies, in order to secure their national interests.

Morgenthau’s Six Principles of Political Realism

Hans Morgenthau was a refugee from Nazi Germany who settled in the United States in 1937, right before the onset of World War II. He was inspired by the thoughts of Thomas Hobbes and Reinhold Niebuhr, a Protestant theologian and political writer. In his book Politics among Nations: The Struggle for Power and Peace, published in 1948, he developed a kind of biological realism, because of his assumption that “social forces are the product of human nature in action”.

According to him, the fundamental aspect of human nature is animus dominandi — the selfish desire for power and domination. Within the realm of international politics, this aspect is the main cause of conflict among states, which are always struggling for power as a way to defend their interests. As a consequence of this, a balance of power arises spontaneously from the deliberate actions of each particular state that is trying to survive in the world.

Morgenthau’s theory is based on the “six principles of political realism”, which he presented in the first chapter of his book. These are prescriptive ideas, intended to systematize Realism within International Relations:

Politics, like society in general, is governed by objective laws that have their roots in human nature: Humans have a natural drive to dominate each other, a general rule that has not changed since it was discovered by the classical philosophers from China, India and Greece. Domestically, the animus dominandi is kept in check by laws, the police and the courts. Internationally, on the other hand, there are no such restraints.
The concept of interest is defined in terms of power: All states act rationally, only taking into consideration their interests when acting in the world. Statesmen should not let their personal morality or preferences stand in the way of pursuing the interests of their respective states. For example, Neville Chamberlain’s appeasement policy likely had a good motive (the attempt to preserve peace), but it ultimately failed. In contrast, Winston Churchill acted in pursuit of national power and was much more successful.
Power and interest are universally defined, but they vary according to the circumstances of time and place: Power is not only military power, but also cultural and economic power, too. The formulation of a country’s foreign policy can be affected by the political, economic and cultural context of said country, influencing the interests that it will have or not.
Universal moral principles cannot be applied to the actions of states: The behaviors of states are contingent upon specific circumstances in which states find themselves. While individuals are free to apply moral principles in their own lives, states should always act in the way that is best for their survival, even if running counter to principles of morality.
The moral aspirations of a particular nation cannot be identified with the moral laws that govern the universe: All nations are tempted to equate their principles and interests with those of the whole universe. However, that is a fallacy. States should guide their political decisions according to their interests while attempting to respect the interests of others. This means that states act in moderation not according to morality, but contemplating the political consequences of their actions.
The political sphere is autonomous: Unlike other schools of thought, Political Realism believes that political interests should only be understood in terms of power, while other interests can be understood in other ways. For instance, economists see interest in terms of wealth, lawyers see it in terms of adhering to norms, and moralists see it in terms of conforming to moral principles. Political realists are aware of economic, legal and moral standards of thought, but are never subordinated to them.

Conclusion

Realism emerged as a response to the failures of Liberalism in the interwar period, deeply rooted in the historical and philosophical insights of figures like Thucydides, Machiavelli, and Hobbes. Authors such as Edward Carr and Hans Morgenthau highlighted the anarchic nature of the international system and the perpetual power struggles among sovereign states. During the Cold War, realist thought gained much prominence, because security issues were prevalent in international politics. Today, Classical Realism, Neorealism, Neoclassical Realism and Critical Realism are the main sources of realist thought in IR. Although they are fundamental for understanding the complexities of international politics, they also face criticism from a series of other theories of international relations.