Realist Theories and Theorists of International Relations

Schematically, we can distinguish two major schools of thought in International Relations, each of which is based on opposite conceptions of the human condition: one is “realist” and the other “idealist.” In both cases, it is an “act of faith” since, beyond their internal logics and their heuristic validations, each one implies a way of seeing man on which a different vision of society is built.

It has become customary to call the international order established at the end of a process whose starting point goes back to the treaties signed by the great powers in 1648 the “Westphalian international system.” The three treaties of Westphalia, whose objective was to stabilize the situation in Europe in the 17th century, are said to be the origin of the basic principles of public international law, namely the equality of sovereign states, the inviolability of borders and non-intervention in the internal affairs of a state. This system, broken under Napoleon I, then restored at the Congress of Vienna (1814-1815), continued thereafter, in spite of everything, until 1914.

In the aftermath of the First World War, the United States felt that the “Westphalian system” ran counter to its vision and interests. The American president, Woodrow Wilson, then proposed an alternative approach to peace that rejected the principle of balance of power in favor of the prevention and resolution of conflicts within the framework of the cooperation of states, within an international organization (the League of Nations created by the Treaty of Versailles in 1919) with a law that would be binding on all. President Wilson, who posited that the interests of states were best served by trade, cooperation, treaties, legal norms, diplomacy, peaceful transactions and international institutions, has since been considered one of the great protagonists of political idealism.

The “realist” tradition is centuries old, but the “idealist” tradition is no less so. It goes back to the debates on the legitimacy of the use of force, on the “just war,” initiated at first by classical authors, such as Thucydides, Plato, Aristotle or Cicero, continued by Saint Augustine and Saint Thomas Aquinas, enriched then considerably by Vitoria and the School of Salamanca, in the 16th century, then, by the Protestants Grotius and Pufendorf, in the 17th century. We find echoes of this today in the work of Michael Walzer. After getting rid of the central dogma of Catholicism, original sin, the idealist tradition developed an ethical-legal reasoning affirming that foreign policy must always promote the Good.

Thus, at the beginning of the twenty-first century, “idealist” theorists and politicians see economic interdependence, democracy and international institutions as essential elements in the construction of peace. But they are not necessarily pacifists; on the contrary, they are often overt or covert warmongers. Let us not forget that the departure of Chancellor Bismarck in 1890 represented the abandonment of Realpolitik in favor of a Weltpolitik, of a nationalist-imperialist type, with an arms race that led to the First World War. Let us not forget either that Jimmy Carter was a peace activist wishing to revitalize the moralizing tradition of the United States, but that Woodrow Wilson, George W. Bush, Hillary Clinton or Barack Obama, to name but a few, did not hesitate to impose their ideas and their institutions by force and war.

The classical realist theory of International Relations was born as a reaction to the belief in the “harmony of interests” shared by the liberal and socialist internationalists of the Western world (including in France, Aristide Briand and Léon Blum) in the 1920s and 1930s. On the eve of World War II, Edward Hallett Carr (The Twenty Years’ Crisis, 1919-1939. An Introduction to the Study of International Relations, 1939), was the first author to use the term “realist” in the analysis of international politics. He criticized the idealism prevalent in academic circles—their normative perspective (“what ought to be”) which does not take into account the real conditions of political practice (“what actually is”).

However, it was after the Second World War that realist theories really took hold in the Anglo-Saxon world. The League of Nations was then widely perceived as the most striking failure of idealist (or even utopian) thinking because it had disdained the importance of nation-state interests and sought to apply democratic principles to an international scene, marked by anarchy and imperialist-type struggles. According to realist authors, the moral approach to international politics had paradoxically encouraged the intensification of conflicts through the discourse of the “just war” to combat the enemies of peace and equity. A “heterothelism” of ends that is deplored in the Bible: “For the good which I will, I do not; but the evil which I will not, that I do” (Romans 7:19).

Criticizing Phantasiepolitik in the name of Realpolitik (a term coined by the liberal Ludwig von Rochau in his 1853 book, Grundsätze der Realpolitik), realist thinking was to dominate during the Cold War. It became the “scientific school” of International Relations, thanks to authors such as Reinhold Niebuhr, Hans Morgenthau, George Kennan, Kenneth Neal Waltz, Nicholas Spykman, Martin Wight, Zbigniew Brzezinski, Henry Kissinger and many others. Hans Morgenthau’s pioneering work, Politics Among Nations: The Struggle for Power and Peace (1948) is particularly worth quoting here (similar postulates can be found in Raymond Aron’s book, Paix et guerre entre les nations, 1962—Peace and War Among Nations). It should be noted that most of these authors had a thorough knowledge of the work of a whole host of “strategists” (theorists and thinkers of war) and not “strategians” (military, actors or practitioners) that are Clausewitz, Sun Tzu, Sun Bin, Vegetius, Machiavelli, Montecuccoli, Schaumburg-Lippe, Guibert, Jomini, Moltke, Grouard, Mahan, Corbett, Douhet, Castex, Rosinski, Fuller, Liddell Hart, Brodie, Beaufre, Coutau-Bégarie, etc.

These “realists” share with the “idealist” authors the conviction that peace or stability is always preferable to war or conflict. But the difference between them lies in the way they conceive the reality of foreign policy and the way the non-war scenario should be implemented. Realism seeks to understand the meaning of foreign policy from an empirical and rational perspective, refusing to judge international political reality through subjective or abstract moral principles. It wants to provide a credible answer to the problem of external instability, arising from periodic global confrontations. The question it intends to answer is: what are the rational and historically identifiable causes that make stability and peace possible?

Realist thinking was hegemonic in academic and political circles until 1990-1991. Thereafter, with the euphoria of the fall of the Berlin Wall and the dislocation of the communist bloc, it experienced a dramatic but short-lived decline. The realism of Samuel Huntington (The Clash of Civilizations, 1996) was quick to respond to the excessive optimism of the admirers of Francis Fukuyama (The End of History, 1992), and the events of 2014-2022 have shaken the certainties of the most confident.

We can identify a sort of small common denominator of realist theories of International Relations and summarize it in the following points:

The major importance of the group and of conflicts between groups. The state remains today the most important human grouping, the main actor on the international scene, and international cooperation has only a limited effect. The state is unitary and rational. It is the only sovereign political unit on its territory and, to ensure its security, it must make the most effective decisions, given its means and the international context. Moreover, the lessons of history must never be neglected or underestimated.
International anarchy: there is no government or world police force that can guarantee respect for international law, and states must therefore rely solely on themselves to defend their interests, ensure their security and sometimes their survival.

The primary motive of states is the pursuit of the national community interest; rational strategic calculation is the tool of collective political actors concerned with defending their interests and obtaining relative (rather than absolute) advantages in comparison with other states. Realism does not deny the existence of irrational conduct, but it focuses on finding elements of rationality. The only truly immoral act for the realist is to act against the interests of the state community. A state has no friends in the political arena; it only has temporary allies.

Power, in relative terms, is the essential criterion of the political game. It is not only the power resulting from all the material means of a state (GDP, demography, military means, capacity to mobilize and manage resources, real and potential allies, internal power structure, ideology and internal and external influence of the elites), but the means it has, compared to those of other states and their interests (the international system). Power is dynamic, not static. International Relations are therefore a perpetual process of negotiation on the distribution and redistribution of scarce or limited resources and goods.

Caution in the use of force: the realist is the opposite of the warmonger; he fears military adventures, he fears ideological blindness, “the spirit of crusade” and generally pleads in favor of wisdom and prudence.

The Centrality of the Notion of Balance in International Relations

Competition and conflict are inherent phenomena in International Relations. Periods of peace are not the consequences of forgetting national interests, but of the balance (bipolar or multipolar) between the forces that shape the international system at a given moment. The participants refrain from upsetting the balance because they are aware of the damaging consequences that an open confrontation could have for them. Any political model is accepted on the condition that its international behavior is moderate, rational, and does not radically and dangerously challenge the international balance prudently established by the great powers.

The realist school does not constitute a monolithic block, and the various authors can sometimes clash or even radically oppose each other. We can distinguish five branches: classical realism (Hans Morgenthau, already mentioned), structural realism or neo-realism (initiated by Kenneth N. Waltz’s work, Theory of International Politics, 1979), offensive realism (with John Mearsheimer, the author of The Tragedy of Great Power Politics, 2001, as its figurehead), defensive realism (systematized after Waltz by the Chinese author Shiping Tang in his book, A Theory of Security Strategy for Our Time. Defensive Realism, 2010) and neoclassical realism (see Gideon Rose’s article, “Neoclassical Realism and Theories of Foreign Policy,” 1998).

Unlike classical realists, for whom man, with his rationality, appetites and passions, is at the center of the international system, neorealists (including Waltz) consider that it is the structure that imposes its conditions on states and their leaders. The neorealist school seeks to constitute a scientific progress (with more theoretical and methodological rigor) compared to classical realism, which does not formulate empirically verifiable propositions. But other realist authors have not failed to criticize the structural or systemic approach, because it denies any ethical dimension of international politics (in opposition to classical realism) and because it proves incapable of explaining the changes and ruptures of the system by revisionist states that challenge the status quo. Other realist theorists have also pointed out that the anarchy of the system should not be exaggerated because some international legal norms nevertheless regulate state action in part. Finally, from a constructivist, clearly anti-realist perspective, some authors have argued that ideas of security and anarchy do not result from the nature of the system, but are the product of social constructs, intersubjective perceptions of states that assume only the worst intentions of other actors.

The critique of structural realism has led to the development of new theories called “offensive realism” and “defensive realism.” Offensive realism asserts that great powers always try to maximize their power to ensure their security. According to Mearsheimer, the only great powers that defend the status quo are those that have achieved a hegemonic position regionally, such as the United States in the Western Hemisphere. As a result, a European Union with genuine strategic autonomy cannot agree with North American interests. Conversely, defensive realism (Waltz, Walt, Shiping Tang) considers that states are content with an appropriate or limited level of power and seek above all to maintain the status quo, the balance within the system. This debate has itself led to the emergence of a theory combining defensive and offensive strategies of states to maximize their security. Finally, neoclassical realism maintains that the scope and ambition of a country’s foreign policy depends primarily on its relative material power and is much less a result of the international structure.

These various realist schools have developed a veritable catalog of strategies and options for responding to a greater or lesser degree of confrontation. These range from aggressive and pre-emptive war, through blackmail, incitement of rivals to enter into a protracted conflict, aiding the one fighting the rival by staying out of the conflict, betting on the likely winner, counterbalancing, appeasement, interference, political destabilization, disinformation, economic coercion, cyberattack, violent action by intelligence services, etc.

One important question divides realist theorists—what kind of balance of power best guarantees peace and stability? The bipolar or the multipolar system? Neorealists favor bipolarity; they believe that multipolarity increases uncertainty and the risk of miscalculation. In contrast, classical realists believe that multipolarity leads to more stability for two reasons: first, the number of actors and the increase in uncertainty leads states to be more cautious; second, the risk of war decreases because states divide their attention and are no longer obsessed with the same rival.

The realist schools have been criticized for their excessive use of a concept considered too polysemous: national interest, which can have a wide range of meanings and justifications. The realist approach to the national interest would ultimately operate more on the basis of a philosophical axiom than on the basis of a scientifically verifiable postulate. Finally, for the most severe critics of the “American empire,” realist theories have only served, since the Cold War, to legitimize American foreign policy. All these criticisms to which the realists are at liberty to reply that no rival paradigm has ever succeeded in presenting in such a complete manner an alternative, descriptive and normative vision of the action of states and the functioning of International Relations.

From the 1990s onwards, many voices announced the decline and exhaustion of the realist school. The end of the Cold War and the decline of inter-state wars convinced many Western international actors that it was appropriate to bury the Westphalian system once again and, conversely, to integrate human rights and the duty to interfere into the international system as a matter of priority. It was, however, an ingenuous refusal to believe that the domination of the West would sooner or later be challenged by the rest of the world. It was to naively believe that political actors in non-Western countries would not perceive that the difference between liberation and invasion lies in who carries out the action; that Sadam Hussein, invader of Kuwait, was a violator of international law, while a similar intervention by the United States in a country holding hydrocarbon and gas reserves was a liberation of an oppressed people.

In 2014, in an article in Foreign Affairs (September-October, 2014) and in a subsequent lecture, University of Chicago professor John Mearsheimer explained, “Why the Ukraine Crisis is the West’s Fault” and predicted the Russian-Ukrainian war. Accused of pro-Putin sympathies, he had in fact tried to expose NATO’s advances and Russia’s security concerns in an objective and dispassionate manner. Less than eight years later, the conflict has become a reality.

Until proven otherwise, the world has become just as “anarchic,” unpredictable and dangerous as it was more than thirty years ago. Realism—and not good feelings—is, today as yesterday, the theoretical approach that best explains the most crucial aspects of the international system.


Arnaud Imatz, a Basque-French political scientist and historian, holds a State Doctorate (DrE) in political science and is a correspondent-member of the Royal Academy of History (Spain), and a former international civil servant at OECDHe is a specialist in the Spanish Civil War, European populism, and the political struggles of the Right and the Left – all subjects on which he has written several books. He has also published numerous articles on the political thought of the founder and theoretician of the Falange, José Antonio Primo de Rivera, as well as the Liberal philosopher, José Ortega y Gasset, and the Catholic traditionalist, Juan Donoso Cortés.


Featured: The Battle of Königgrätz on July 3, 1866, by Georg Bleibtreu; painted ca. 1869.