International relations refer to the relationships between actors that engage in international politics, such as nation-states, nongovernmental organizations, multinational corporations, and international organizations. The field of scientific and philosophical studies of these relations is, most often, also called international relations, while it is also known as international studies, international politics, or international affairs. International relations is a complex and multifaceted field. In European academia, international relations is considered an independent interdisciplinary field, while in the US it is regarded as a part of political science.

Many approaches to international relations differ in their epistemological, methodological, theoretical, philosophical, and ideological perspectives. In terms of epistemological perspective, approaches can be divided into positivist, interpretivist, and post-positivist approaches. Methods used in international relations can be quantitative and qualitative. The most important distinction between approaches to international relations is in their theoretical perspectives.

     Theoretical Approaches to International Relations

Realism is one of the oldest and most influential theories in international relations. It is grounded in the belief that the international system is anarchic, meaning there is no overarching authority above states. According to realists, states are rational, self-interested actors that prioritize survival and power. They operate in a zero-sum world where gains for one often mean losses for another. Classical Realism, rooted in the works of thinkers like Thucydides and Machiavelli, emphasizes human nature as inherently power-seeking. Neorealism or Structural Realism, developed by Kenneth Waltz, shifts the focus from human nature to the anarchic structure of the international system, which compels states to compete for power and security. Most notable representatives of realism are  Hans Morgenthau, John Herz, Raymond Aron, Edward H. Carr, Anthony Lang, Richard Ned Lebow, Michael C. Williams, Robert Gilpin, Henry Kissinger, Susan Strange, and Kenneth Waltz.

Liberalism Liberalism presents a more optimistic view of international relations. It argues that cooperation is not only possible but common, as self-interest most often leads to cooperation, not conflict, and it can be fostered through democratic governance, economic interdependence, and international institutions. Liberal theorists who focus on politics emphasize the role of international organizations, international law, and human rights, as they improve cooperation and transparency and reduce uncertainties. The main idea is that the democratization of countries leads to peace, as democracies are less likely to go to war with each other. Liberal theorists who focus on the economic side of international cooperation argue that free trade among countries brings more economic prosperity than wars and conflicts. Modern liberal theories include Neoliberal Institutionalism, which focuses on how institutions like the UN and WTO help mitigate anarchy by fostering cooperation and reducing transaction costs. Some of the most influential liberal theorists are Norman Angell, Charles Beitz, Michael Doyle, Francis Fukuyama, David Held, John Hobson, Stanley Hoffmann, Richard Rosecrance, Woodrow Wilson, and Alfred Zimmern.

English School (Grotian or International Society) bridges the gap between realism and liberalism by emphasizing the concept of an “international society.” It argues that despite the anarchic nature of the international system, states form a society bound by common interests, norms, and institutions. Scholars like Hedley Bull advocate for a “middle way” that acknowledges both the realities of power politics and the role of shared values in maintaining order. Other notable theorists who are proponents of this school include  Herbert Butterfield, Adam Watson, John Vincent, Martin Wight, Barry Buzan, Timothy Dunne, Robert Jackson, Nicholas Wheeler, Terry Nardin, Michael Walzer, and Barak Mendelsohn.

Constructivism offers a sociological and ideational perspective, asserting that international relations are not only shaped by material forces but also by intersubjectively shared ideas, identities, norms, rules, discourse, and social interactions. Constructivists such as Alexander Wendt argue that “anarchy is what states make of it,” meaning that states tend to do more than just survive in an anarchical system, and that the structure of the international system depends on how states perceive and interact within it. Constructivism emphasizes the importance of culture, historical context, and language in shaping state behavior and international outcomes. Unlike realism and liberalism, it does not assume fixed national interests but sees them as socially constructed and subject to change. In addition to Wendt, other influential proponents of constructivism are Martha Finnemore, Michael Barnett, Nicholas Onuf, and Friedrich Kratochwil.

Neorealism and Neoliberalism - these two approaches combine tenets of classical realism and liberalism with the goal of developing causal scientific theories of international politics. The starting viewpoint of both theories is that states conduct themselves rationally in an anarchical global system, and that rational action allows building causal hypotheses that can be tested and developed into a nomothetic science. Keneth Waltz is the main proponent of neorealism, while Robert Keohane and Joseph Nye are the most important bellwethers of neoliberalism.

Foreign Policy Analysis focuses its research on a small group (political leaders and elites) of foreign policy decision makers in each country. These decision makers use their imperfect rational capabilities to interpret important information and thus often make wrong or disastrous policies. Authors who influenced this approach include Harold and Margaret Sprout, Richard Snyder, James Rosenau, Stephen Walker, Margaret Hermann, Charles Hermann, Richard Herrmann, and Martha Cottam.

Critical Theory seeks to understand and critically examine how the theories and viewpoints of traditional approaches to international relations were originally formed, and how they might influence negative outcomes in the international system. Most notable exponents of critical theory are John Burton, Robert Cox, Richard A. Falk, André Gunder Frank, Johan Galtung, Vladimir I. Lenin, and Andrew Linklater.

Poststructuralism bases its perspective on theories of authors such as Jacques Derrida and Michel Foucault to understand the subtle, localized, and fragmented use of power. Authors who contributed to this approach include Richard Ashley, Robert B. J. Walker, David Campbell, and James Der Derian.

Neo-Marxist Theory - dependency theory and World-systems theory applied Marxist concepts of exploitation and domination on a global scale – similar to relations between the capitalist class and proletariat, powerful countries and empires are exploiting and dominating other countries or their colonies within the international economic system. Gramscian perspectives, inspired by the work of Antonio Gramsci and introduced by authors like Robert Cox and Stephen Gill, focus on the ideological indoctrination of exploited and dominated countries by the powerful countries.

Feminist international relations theories challenge the masculine assumptions of wars and aggression that form the basis of mainstream theories of international relations. This approach is championed by authors such as Jean Bethke Elshtain, J. Ann Tickner, Elizabeth Hutchings, Spike Peterson, Christine Sylvester, and Cynthia Enloe.

International organization authors like Karl Deutsch, David Mitrany, Ernst Haas, John Ruggie, and Robert Keohane study how organisations and practices of co-operation regulate relations among states.

Some of the scientific subfields of international relations are: security studies (international security), Civil society studies, international ethics, international political economy, and international law.

References:

Albrow. The Global Age: State and Society Beyond Modernity (1996);

       -     Global Civil Society (2011);

       -     Globality and the Absence of Justice (2011);

Ang. Cultural Diplomacy: Beyond the National Interest? (2016);  

Aron. Peace and War: A Theory of International Relations (1966, in French 1962);

Chase-Dunn. BRICS and the New American Imperialism: Global Rivalry and Resistance (2020);

Comte. System of Positive Polity, 2 vols. (2018, in French 1851-1854);  

Held. Democracy and the Global Order: from the Modern State to Cosmopolitan Governance (1995);

       -     Cosmopolitan Democracy: an Agenda for a New World Order (1995);

       -     Global Covenant (2004);

       -     Global Policy: Power, Governance and Accountabillity (2014);

Myrdal A. The Game of Disarmament: How the United States and Russia Run the Arms Race (1977); 

       -     Dynamics of European Nuclear Disarmament (1981);

Offe. Europe Entrapped (2015).