Approaches to the Study of International Relations

Every IR theory is an answer to one question: what does anarchy make states do? Realists say compete, liberals say cooperate under the right institutions, Marxists say the question is wrongly posed, and constructivists say anarchy is whatever states make of it.

This is chapter 39 of the PSIR Optional Notes, from the part on International Relations in the Paper II syllabus. The complete book is a free download.

Idealism

The 2024 paper asked for the facets of the idealist approach and its contemporary relevance.

Its philosophical roots are Kantian: Perpetual Peace (1795) argues that republican constitutions, a federation of free states and cosmopolitan right together make peace possible, which is the ancestor of democratic peace theory. Its immediate context is the First World War and the conviction that the balance of power had failed.

Core tenets. Human nature is not fixed and is capable of improvement through education and institutions. War arises from misunderstanding, secret diplomacy, arms races and undemocratic government, all of which are remediable. There is a harmony of interests: the true interests of states do not fundamentally conflict. International law and organisation can substitute for the balance of power. Public opinion, once informed, is a force for peace. Self-determination removes a principal cause of war.

Programme. Wilson’s Fourteen Points (1918); the League of Nations with collective security; the Permanent Court of International Justice; the Kellogg-Briand Pact of 1928 renouncing war as an instrument of national policy; and disarmament conferences.

The realist critique. E.H. Carr‘s The Twenty Years’ Crisis (1939) is the decisive text: idealism is utopian because it mistakes aspiration for analysis, and the harmony of interests is an ideology of satisfied powers, since those who benefit from the status quo naturally believe that everyone’s interest lies in preserving it. The League’s failure over Manchuria in 1931 and Abyssinia in 1935 supplied the evidence.

Contemporary relevance. Substantial, and the answer should say why rather than merely asserting it. The United Nations, the international human rights regime, the International Criminal Court, the laws of armed conflict, arms-control treaties and climate agreements are all idealist in lineage. Democratic peace theory, that liberal democracies do not fight one another, is the most robust empirical generalisation in the field. Neoliberal institutionalism is idealism rebuilt on realist foundations. The qualification: the record of collective security remains poor, the Security Council’s veto reflects power rather than law, and enforcement remains selective, which is why the tradition is better described as a persistent aspiration with real institutional residue than as a description of how the system works.

Realism

Classical realism

Hans Morgenthau‘s Politics Among Nations (1948) states the six principles: politics is governed by objective laws rooted in human nature; the main signpost is interest defined in terms of power; interest is a universal category but its content varies with circumstance; universal moral principles cannot be applied to state action in their abstract formulation; the moral aspirations of a particular nation are not the moral laws of the universe; and the political sphere is autonomous from the economic, legal and moral.

Its lineage: Thucydides on the Melian dialogue, Machiavelli in Chapter 11, Hobbes’s state of nature in the same chapter, and Carr.

Neorealism

Kenneth Waltz‘s Theory of International Politics (1979) relocates the explanation. Human nature cannot explain variation, since it is constant. What explains state behaviour is the structure of the international system, defined by three elements: its ordering principle, which is anarchy, meaning the absence of a common government rather than chaos; the absence of functional differentiation among units, since all states must perform the same basic functions; and the distribution of capabilities, which is the only variable that changes.

From this follow: the security dilemma, in which measures one state takes for its own security reduce the security of others; the self-help imperative; relative gains concerns, since a state must care not only whether it gains but whether it gains less than a rival; and balancing as the recurrent behaviour of the system. Waltz’s controversial corollary is that bipolarity is more stable than multipolarity, since there are fewer dyads and less miscalculation.

Offensive and defensive realism

The 2023 paper asked for this distinction directly.

Mearsheimer’s additional claim, the stopping power of water, is that oceans prevent global hegemony, so states aim at regional hegemony and at preventing any other state achieving it elsewhere. This is the standard theoretical frame for reading United States policy toward China, and it is what the 2024 question about NATO as an instrument of American hegemony is testing.

Neoclassical realism

The recent variant, in Rose, Zakaria and Schweller, restores domestic variables: systemic pressures are the independent variable, but they are translated into policy through the intervening variables of leaders’ perceptions, state strength relative to society, and domestic coalitions. It is the most useful realist frame for explaining why two states facing similar structural conditions behave differently.

Marxist approaches

The premise is that the state-centric question is wrongly posed: the primary units are classes and the primary structure is the world capitalist economy.

• Classical imperialism. Lenin‘s Imperialism, the Highest Stage of Capitalism (1916): monopoly capital, the fusion of bank and industrial capital into finance capital, the export of capital rather than goods, the territorial division of the world among trusts, and war as the mechanism of redivision. Hobson’s earlier underconsumptionist account supplied the economic argument without the revolutionary conclusion.
• Dependency. Underdevelopment as a product rather than a stage, treated in Chapter 35.
• World-systems. Wallerstein’s core, semi-periphery and periphery, also Chapter 35.
• Neo-Gramscian. Robert Cox‘s formulation is the one to quote: theory is always for someone and for some purpose. He distinguishes problem-solving theory, which takes the world as given and makes it work better, from critical theory, which asks how the order came about and whether it can change. Hegemony at the world level is a fit between material capabilities, ideas and institutions.

Functionalism and systems theory

Functionalism

David Mitrany‘s A Working Peace System (1943) argues that peace should be built not by constitution-making but by form following function: cooperation should begin in technical, non-controversial areas where needs are shared, postal services, health, transport, and the resulting agencies should be organised around the task rather than around territory. Success in one area generates the habit and the demand for cooperation in others, so loyalty gradually transfers from the state to functional bodies. His slogan is peace by pieces.

Ernst Haas converts this into neofunctionalism to explain European integration. The key mechanism is spillover: functional, when integration in one sector creates pressures in adjacent ones; political, when interest groups and elites reorient their expectations and activities toward the new centre; and cultivated, when supranational institutions themselves push integration forward. The difference from Mitrany is that Haas expects, and welcomes, political integration rather than treating it as unnecessary.

The critiques: functionalism underestimates how political apparently technical questions are; spillover has repeatedly stalled, which produced Haas’s own later admission that the theory was obsolescent; intergovernmentalists such as Hoffmann and Moravcsik argue that integration proceeds only as far as the largest member states’ preferences allow.

Systems theory

Morton Kaplan‘s System and Process in International Politics (1957) models six system types with rules of behaviour attached: the balance of power system, loose bipolar, tight bipolar, universal, hierarchical and unit veto. Its value is that it makes explicit what behaviour each structure requires; its weakness is that only two of the six have ever existed.

Waltz’s structural realism is itself a systems theory, and the more durable one, because it uses structure to explain rather than to classify.

Constructivism

Not in the syllabus list, but examinable and increasingly expected. Alexander Wendt‘s “Anarchy Is What States Make of It” (1992) and Social Theory of International Politics (1999) make three claims: structures are constituted by shared ideas rather than by material forces alone; identities and interests are constructed by those shared ideas rather than given by nature; and agents and structures constitute each other.

The illustrative point to use: five hundred British nuclear weapons are less threatening to the United States than five North Korean ones, which no purely material theory can explain. Wendt’s three cultures of anarchy, Hobbesian where others are enemies, Lockean where they are rivals, and Kantian where they are friends, show that anarchy has no single logic.

Read the rest. This chapter is one of 58 in the complete PSIR Optional Notes, covering Paper I and Paper II in full — free to download.

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