Political Realism

In brief

Realism is the oldest and most durable way of thinking about relations between states. Its claim is simple and unsettling: because there is no world government, no sovereign standing above nations to enforce agreements or punish aggression, each state is finally responsible for its own survival, and must look to its own power to secure it. In that condition, the behavior of states is driven less by ideals, treaties, or the character of their rulers than by the distribution of power and the pursuit of interest. Realists do not celebrate this. They claim to describe it. A statesman who acts as though the world were governed by law and goodwill, they argue, will be outmaneuvered by one who understands that it is not, and the cost will fall on his own people.

The tradition has a long spine. Thucydides diagnosed it in the fifth century BCE; Machiavelli gave it a manual in the sixteenth; Hobbes supplied its logic in the seventeenth; and in the twentieth century E. H. Carr and Hans Morgenthau made it a named academic school. Later realists built more formal versions of the argument, but the core remained: in a world without a ruler, states pursue power to survive.

The full treatment

The problem it answers

Every political order inside a state rests, ultimately, on a monopoly of legitimate force. Courts settle disputes; police enforce judgments; a sovereign has the last word. Realism begins by noticing that between states, none of this exists. There is no global sheriff. Treaties are promises with no enforcer above the parties. International institutions have no army of their own and no power to compel a great state that refuses to comply. This condition is what realists mean by anarchy: not chaos or disorder, but the simple absence of a higher authority.

The question realism answers is what follows from that absence. Its answer is that states are thrown back on self-help. If no one will guarantee your security, you must guarantee it yourself, which means accumulating power and watching the power of others. The pursuit is not greed but prudence. Even a state that wants nothing but to be left alone cannot be sure its neighbor is equally content, and cannot afford to be wrong, so it arms, allies, and hedges. This is the logic later realists would name the security dilemma: measures one state takes for its own safety look like threats to another, which responds in kind, and both end up less secure though neither wanted a fight. (See the-security-dilemma.)

How it works: states, survival, power

Classical realism rests on a picture of the state and a picture of human nature. The state is treated as a unitary actor: whatever its internal quarrels, it faces the outside world as a single agent with a single overriding interest, which is to survive. It is also treated as broadly rational: it weighs costs and benefits and pursues its interest defined as power. And it operates in a system where the only thing that reliably restrains a state is the countervailing power of other states.

From these premises realism derives its characteristic moves. It expects alliances to form against whoever grows too strong, because states fear concentrated power more than they trust the intentions behind it. It expects the strong to do what they can and the weak to suffer what they must. It expects that the ambitions of statesmen will be checked less by conscience than by capability. Power here is not only armies and economies but the capacity to make others do what they otherwise would not, and to resist the same pressure oneself. (See power.) The balance of power, the recurring tendency of states to coalesce against a would-be dominator, is realism's central mechanism and its nearest thing to a law. (See the-balance-of-power.)

The key text: the Melian Dialogue

Realism's founding scene is a conversation Thucydides reconstructs in his History of the Peloponnesian War. In 416 BCE, during the long war between Athens and Sparta, the powerful Athenians demanded that the small, neutral island of Melos submit and pay tribute. The Melians appealed to justice, to the gods, to their right to remain neutral, to the hope that Sparta would come to their aid. The Athenian envoys swept all of it aside with a single sentence that has echoed through the tradition ever since: the strong do what they have the power to do, and the weak accept what they have to accept. Justice, they said, is only a question between equals in power; between the strong and the weak, the strong rule and the weak give way. The Melians refused to submit. Athens besieged the island, killed the men of military age, and sold the women and children into slavery.

Thucydides does not editorialize, and that restraint is part of why the passage endures. He lets the outcome speak. Realists read the Melian Dialogue as the clearest statement of their case: appeals to right that are not backed by power are not answered, they are ignored, and a people that stakes its survival on the goodness of the strong may not survive. Critics read the same passage as a warning rather than a lesson, and note that Athens, drunk on its own strength, went on to overreach and lose the war. Thucydides leaves room for both readings, which is why he is claimed by realists and quoted against them in the same breath.

Distinctions that matter

Realism is a family, not a doctrine, and its branches disagree sharply. The oldest split is over where the pressure to seek power comes from. Classical realists such as Morgenthau located it partly in human nature: an ineradicable drive to dominate, the animus dominandi, that shows up in individuals and is magnified in states. Structural realists, following Kenneth Waltz, rejected this. For them the cause is not human nature at all but the structure of the system: even states run by saints would compete for power, because anarchy alone forces them to. Strip out human nature and the argument still goes through. This structural turn, sometimes called neorealism, is treated in its own entry. (See structural-realism.)

A second split runs through the structural camp itself, over how much power a state needs. Defensive realists argue that states seek only enough power to be secure, that seeking more provokes the balancing that undoes them, so the sensible aim is a comfortable sufficiency. Offensive realists, most prominently John Mearsheimer, argue that because no state can ever be certain of another's future intentions, the only safe amount of power is as much as possible, ideally regional dominance, so great powers are pushed to expand whenever they can. The disagreement is not academic: it produces opposite predictions about whether a rising power will be satisfied or relentless.

Finally, realism should not be confused with cynicism or with warmongering. Its leading figures were often the most cautious voices in their societies. Morgenthau opposed the Vietnam War; Kenneth Waltz warned against imperial overreach; and it was a group of prominent realist scholars who publicly argued in 2002 that invading Iraq was strategically unwise. Realism counsels the disciplined pursuit of the national interest and a wary respect for the limits of power. That often means restraint, not adventure.

Lineage

Realism claims the longest pedigree of any tradition in the study of politics. Its origin is Thucydides (c. 460 to c. 400 BCE), whose account of the Peloponnesian War treats fear, honor, and interest as the perennial drivers of state behavior. Its Renaissance voice is Niccolo Machiavelli (1469 to 1527), whose The Prince (1532) judged rulers by whether they preserved the state, not by whether they kept the conventional virtues, and who insisted that a prince who wishes to survive must learn how not to be good.

The tradition's decisive philosophical foundation is Thomas Hobbes (1588 to 1679). Hobbes argued that individuals in a state of nature, with no common power over them, live in a war of all against all, and he noted in Leviathan (1651) that sovereigns stand toward one another in exactly this posture: there is no Leviathan above the Leviathans. That observation is the direct ancestor of the anarchy premise, and realism descends from it more than from any other single source. (See thomas-hobbes.)

Realism became a self-conscious school only in the twentieth century, in reaction to the aftermath of the First World War. E. H. Carr (1892 to 1982), in The Twenty Years' Crisis (1939), attacked what he called the "utopianism" of those who believed the League of Nations and international law could abolish power politics, and argued that their neglect of power had helped bring on the catastrophe unfolding around him. Hans Morgenthau (1904 to 1980), a German-Jewish emigre to the United States, then wrote Politics Among Nations (1948), the textbook that taught a generation of American scholars and diplomats to see the world in terms of interest defined as power. The line continues through Reinhold Niebuhr's theology of human sinfulness in politics, through the diplomatic realism of George Kennan, and into the structural reformulation of Kenneth Waltz's Theory of International Politics (1979), which recast the whole tradition on a new and more austere foundation.

The strongest case for it

Realism's first strength is that it predicts the recurring patterns of history better than its rivals hoped to. States with very different ideologies, religions, and constitutions have behaved in strikingly similar ways when placed in similar strategic positions. Alliances form against the strong; balances re-emerge after they are broken; rising powers and declining ones tend to collide. The pattern repeats across millennia and across cultures, which is what one would expect if it were driven by the structure of the situation rather than by anyone's ideals. Realism explains why democracies have conquered and tyrannies have kept the peace, why allies of yesterday become rivals tomorrow, and why the same states that sign treaties break them when the balance shifts.

Its second strength is honesty about the stakes. Realists insist that in a world without an enforcer, a leader's first duty is to keep his people safe, and that a moralism which ignores power can be not just naive but lethal. Carr's charge against interwar idealism landed hard precisely because the decade that followed proved it. A theory that reminds statesmen that hope is not a strategy, and that the wolf does not respect the sheep's appeal to justice, has earned a permanent place at the table.

Its third strength is analytic economy. Structural realism in particular makes few assumptions, applies across every era, and yields testable expectations about balancing, alliance, and the behavior of great powers. It does not need to know what is in a leader's heart to say something useful about what his state is likely to do. That parsimony is why realism remains the baseline that other theories must beat.

The strongest case against it

The objections are serious and come from every direction.

The liberal tradition argues that realism systematically underrates everything that dampens conflict. Trade binds states together and makes war costly; international institutions lower the price of cooperation, share information, and let states make credible commitments; and the internal character of regimes matters, since democracies have almost never gone to war with one another, a regularity realism cannot explain and that liberals treat as a genuine finding. Robert Keohane's work on institutions and the broad literature on the democratic peace press this case hard. (See liberalism-in-international-relations.) Realists reply that trade has not stopped wars before (the great powers of 1914 were deeply interlinked) and that institutions reflect power rather than constrain it, but the anomalies remain.

Constructivists mount a deeper challenge: they deny that anarchy has any fixed meaning at all. Alexander Wendt's famous formulation, "anarchy is what states make of it," holds that whether a rival is treated as an enemy, a competitor, or a friend is a matter of shared ideas and identities, not of structure. The same distribution of power produced deadly fear between the United States and the Soviet Union and easy trust between the United States and Britain. If the response to power depends on what states believe about one another, then realism has mistaken a cultural artifact for a law of nature. (See constructivism-in-international-relations.)

There is a historical objection too. Realism's own predictions have failed at crucial moments. It largely did not foresee the peaceful end of the Cold War, in which a superpower dismantled its own empire without being defeated; Waltz's structural theory expected the balance to persist. And it struggles to explain the dense, rule-bound cooperation of the European Union or the long democratic peace among the industrial democracies.

Finally, critics charge realism with a moral evasion dressed as clear sight. To say the strong do what they can and the weak suffer what they must is, they argue, not a neutral description but a self-fulfilling one: treat the world as a jungle and you help make it a jungle. The just-war tradition and much of international law insist that even between states, some acts remain wrong whatever the balance of power, and that the realist's shrug at the fate of Melos is a choice, not a discovery.

Where it stands now

Realism remains the tradition every other school of international relations argues with, which is itself a measure of its standing. It never became the only game, and its structural version took real damage from its failure to anticipate the end of the Cold War and from the constructivist attack on its core premise. Liberal institutionalism and constructivism grew up in part as answers to it, and in the academy realism is now one paradigm among several rather than the reigning orthodoxy it was in Morgenthau's day.

Yet it has proven impossible to retire. The return of great-power rivalry, above all the tension between the United States and a rising China, has revived exactly the questions realists have always asked: whether a dominant power and a rising one can avoid collision, how alliances will re-form, whether interdependence will restrain or merely raise the cost of conflict. Offensive realists in particular read the present as confirmation of their long-standing warnings. Whether they are right is contested, but the vocabulary is theirs. When statesmen and analysts reach for the ideas of balance, deterrence, and the national interest, they are reaching, whether they know it or not, into a tradition that runs back to a conversation on a doomed island twenty-four centuries ago.

Test yourself

Think of a recent confrontation between two countries that you followed closely. Ask first what a realist would say: how did the distribution of power, and each side's need to secure itself, shape what happened, regardless of the leaders' stated ideals? Then ask what the realist account leaves out: did trade, institutions, domestic politics, or simply what each side believed about the other change the outcome in a way pure power cannot explain? Notice which account felt more true to you before you started reasoning, and whether that was evidence or temperament.