Major Debates in International Relations

The discipline of international relations has developed since the early twentieth century as a field enabling the understanding of global politics, continuously evolving in both its academic and practical dimensions evolution. During this process, the fundamental theoretical cleavages and methodological approaches within discipline have over time crystallized into four major debates that have defined the framework of international relations theory.

These debates have offered different perspectives on how to understand the nature of the international system, the roles of actors, and the interactions between states on. First, the Idealism-Realism debate focused on how peace could be achieved and what the fundamental motivations of states were. This was followed by the Behavioralism-Traditionalism debate, which highlighted a methodological divide by raising the question of how far scientific methods could be applied to the discipline.

The Neorealism-Neoliberalism debate centered on state-centric analysis, mutual interdependence, and the role of international regimes. Finally, the Positivism-Postpositivism debate expressed a fundamental division over how knowledge should be acquired in international relations studies and on what epistemological and methodological foundations the discipline should be built.

These debates have been more than mere intellectual divisions within academia; they have also been decisive in shaping states’ foreign policies and understanding the international order. The discipline’s core theoretical orientations and methodological cleavages have deepened international relations scholarship and contributed to the multidimensional analysis of global politics.

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World War, the discipline of international relations began seeking answers to questions about why wars broke out and how they could be prevented. Pre-war idealism was grounded in the belief that human nature was inherently good and that peace could be sustained through cooperation among states and mechanisms of international law. However, the devastation unleashed by the war demonstrated the inadequacy of idealist approaches in international politics. Escalating crises in world politics from the 1930s, the rise of authoritarian regimes, and the failure of the League of Nations accelerated the collapse of idealism and paved the way for the rise of realism.

Idealist Arguments

Idealists prioritized moral values and the supremacy of law in international relations, focusing on how the world ought to be. They argued that states should not merely be actors pursuing their own interests but should also be structures promoting peace and cooperation. The works of Grotius, Locke, and Kant, along with Woodrow Wilson’s discourses, formed the foundational pillars of idealism.

According to idealists, war is an accidental condition and peace can be achieved through instruments such as strengthening international law, institutionalization, trade, open diplomacy, self-determination, and disarmament like. Events such as the creation of the League of Nations, the Locarno Era, the Briand-Kellogg Pact, and the London and Washington Sea Disarmament Treaties were seen as steps supporting these idealist views.

Human Nature and the Source of Conflict

At the heart of idealism lies the belief that humans are inherently good. It was argued that individuals are not inherently malicious and that war and conflict arise not from human nature but from environmental factors. Humans are more inclined toward cooperation and mutual aid, but states’ exploitation of individuals as a vehicle to maximize their own interests leads to war.

Preventing War and Abolishing Secret Diplomacy

According to idealists, the first step to prevent war is the abolition of secret diplomacy. Negotiations conducted behind closed doors create an atmosphere of mistrust and deepen international crises. Therefore, open diplomacy and transparent international relations must be encouraged.

Multilateral Cooperation and Collective Security

Idealists argue that states should not act alone to ensure security but should engage in collective and multilateral cooperation. Instead of bilateral agreements, broad-based international organizations should be established, and disputes among states should be resolved through diplomatic and mediation mechanisms.

Self-Determination and Strengthening Democratic Institutions

The principle of self-determination, recognized as the right of peoples to determine their own destiny, is a factor contributing to international peace. Its widespread adoption would encourage the development of democratic institutions and prevent authoritarian regimes from pursuing warlike policies. The proliferation of democratic governance has been viewed as one of the foundational pillars of a safer and more stable international system.

Authoritarian Regimes and Their Tendency Toward War

Idealists argue that non-democratic regimes are more prone to war. The absence of accountability mechanisms and the disregard for the public’s peaceful demands lead authoritarian regimes to adopt more aggressive foreign politics strategies.

Strengthening International Law and Institutions

According to idealism, strengthening international law mechanisms will play a preventive role against war. The principle of the rule of law will make it possible to resolve interstate conflicts without resorting to armed struggle. The establishment of the Permanent Court of International Justice (1921) and the signing of the Briand-Kellogg Pact (1928) are important examples of these efforts. However, such initiatives failed in practice to prevent wars.

Realist Criticisms and the Rise of Realism

Realists criticized idealists for viewing states as actors guided by moral norms, asserting that the fundamental dynamic of the international system is power and the struggle for interests. States, they argued, should prioritize securing their security and enhancing their power over adhering to moral principles. To them, the international law and diplomatic norms advocated by idealists proved inadequate against states’ calculations of interest.

In this transformation process, thinkers such as Reinhold Niebuhr, E. H. Carr, and Hans Morgenthau played a crucial place in theoretically shaping realism. Niebuhr argued that while individuals could be moral, states were actors that prioritized their interests. In his view, moral ideals alone could not determine outcomes in international relations, and states should turn to policies of balance of power. In his 1932 work Moral Man and Immoral Society, he emphasized that preventing war required attention not only to moral values but also to the struggle for power.

Similarly, E. H. Carr labeled idealists as “utopians” and defended the foundational principles of realism, arguing that moral and legal norms could not be decisive in international relations. In his work The Twenty Years’ Crisis, he criticized the fundamental assumptions of idealist thought. According to Carr, moral and intellectual theories are not universal principles but products of specific historical conditions and struggles for interest. The moral and legal norms advocated by idealists, he claimed, were in fact discourses designed to protect the interests of powerful states.

Carr opposed the idealist notion of a “harmony of interests” (common) among all states, arguing that this understanding merely disguised powerful states’ own interests as “universal interests.” For him, international peace could only be sustained as long as it served the interests of powerful states. Peace, he argued, was not the result of a universal moral order but of the balance of power, and major powers used this peace discourse to reinforce their own dominance.

Hans Morgenthau systematized realism and laid the foundation for the discipline of international relations. In his 1948 work Politics Among Nations, he demonstrated that international politics is “directed by interests” and that “power is the most important variable.” According to him, states are rational actors whose primary goal is to ensure national security and protect their interests. Morgenthau placed the concept of balance of power at the forefront, arguing that wars could be prevented not only by moral appeals but also by a credible deterrent strategy.

In conclusion, idealism’s optimistic approach to peace was rapidly criticized from the 1930s onward, and realism came to be accepted as the fundamental determinant of international politics. Niebuhr’s interpretation of human nature, Carr’s critiques of idealism’s failures, and Morgenthau’s power- and interest-centered analysis ensured realism’s enduring place in the discipline of international relations. The competitive struggle of states based on power and the anarchic nature of the international system became the core arguments of realism.

Second Great Debate: Traditionalism – Behavioralism (1950–1970)

From the 1950s onward, the discipline of international relations entered a new debate centered on scientific methodology method and stage. Following the first debate between realism and idealism, this time traditionalists clashed with those embracing new methodological approaches emerging in the social sciences.

This discussion, rooted in methodological differences between traditionalists and behavioralists, focused on the place of scientific methodology in the discipline of international relations. Traditionalists sought to understand international relations through historical, legal, and philosophical perspectives, while behavioralists argued that quantitative analysis, system models, game theory, and statistical methods used in the natural sciences could be applied to international relations studies.

This debate transformed the nature of the discipline and marked a significant breaking point in its process of scientificization.

Rise of Behavioralism and Its Core Arguments

From the 1950s onward, behavioralism began to influence the discipline of international relations as an extension of the scientific transformation occurring in other areas of the social sciences. Primarily led by American academics, this approach argued that international relations studies needed to be grounded in a more scientific and empirical foundation.

Behavioralists began challenging realism’s claim that the international system consists of states competing for power, arguing that this view was too narrow and restrictive. They questioned the assumption that the state is a unitary and rational actor, emphasizing that international politics could not be explained solely through power struggles. They also contended that the concept of power had been oversimplified and that non-security factors—economic, social, and psychological—had been neglected.

Some academics criticized realist assumptions, noting that systematic evidence supporting them was scarce and that realist arguments were often vague and lacking in precision. Behavioralists claimed to offer a conceptual and methodological alternative to the traditional methodologies used in international relations.

Behavioralist methodology aimed to develop a systematic approach to analyzing international relations within the framework of scientific laws and argued that methods used in the natural sciences could be adapted to the social sciences.

Scientific Method and Empirical Research

Behavioralists argued that international relations should be studied within the framework of scientific laws and claimed that scientific techniques such as observation, measurement, and experimental analysis could be applied to international relations studies. For example, this opinion attempted to correlate states’ foreign policy preferences with variables such as geographic size, GNP, per capita income, population size, and energy consumption.

Questioning the Scientific Validity of Traditional Methods

Behavioralists criticized traditionalists’ methods as unscientific, asserting that such studies remained largely at a philosophical level. While traditional approaches analyzed qualitative data such as historical events, diplomatic documents, and memoirs of statesmen, behavioralists adopted a research approach based on statistics, simulation, and quantitative analysis.

New Methodological Approaches and Models

The behavioralist school developed various approaches attempting to explain international relations through modern social science methodology. These include:

• System Models (Morton Kaplan)
• Decision-Making Approach (Richard Snyder)
• Game Theory
• Simulation Techniques
• Conflict Analysis

Many methodologies used in foreign policy analysis today are based on the work conducted by behavioralists during this period.

Traditionalist Criticisms and Responses

In response to behavioralist claims, traditionalists argued that international relations could not be analyzed solely through quantitative methods and was too complex to be explained by scientific laws. For traditionalists, international relations is a field requiring consideration of human nature, history, and diplomacy.

Traditionalists criticized behavioralists for failing to understand the real nature of international relations and for ignoring the human factor. International relations cannot be reduced to statistics alone; historical context and cultural elements must also be taken into account. For instance, Hedley Bull argued that behavioralists neglected theory, overemphasized models and empirical studies, and thereby distorted the discipline harm.

Another criticism was that behavioralists ignored the most important issues and focused excessively on irrelevant variables. For example, prioritizing variables such as economic size and energy consumption over core elements like power and security was seen as a misdirection from understanding the fundamental nature of international relations.

Impact and Legacy of Behavioralism

Behavioralist methodology introduced scientific methods into the discipline of international relations but failed to generate the expected theoretical innovations.

• Although great emphasis was placed on data collection and analysis, criticism emerged that no new theoretical frameworks emerged from this process.
• Neo-realism, a developed version of realism, continued to dominate the discipline of international relations.

In conclusion, the Traditionalism-Behavioralism debate played a critical role in the methodological transformation of the discipline of international relations and contributed significantly to its scientificization. However, because behavioralism could not resolve all its problems, international relations scholarship has increasingly turned toward new methodologies that integrate both quantitative and qualitative approaches.

Third Great Debate: Neo-Realism and Neo-Liberalism (1970–1990)

From the 1970s onward, while realism’s dominance in the discipline of international relations continued, new approaches emerged due to perceived shortcomings in realism together. During this period, two theories—Neo-Realism and Neo-Liberalism—offered new explanations of how the international system functions and initiated the discipline’s third great debate.

While classical realists such as E. H. Carr, Hans Morgenthau, and Reinhold Niebuhr explained international politics in terms of power and interest competition, neo-realism, developed in the 1970s, constructed a new theory centered on the structural characteristics of the international system.

In contrast, Neo-Liberalism (Institutional Liberalism) argued that economic, social, and institutional cooperation, not power competition, were also decisive in international relations. Thinkers such as Robert Keohane and Joseph Nye contended that the international system was not composed solely of states and that transnational actors, international organizations, and multilateral interdependencies also needed to be considered.

This debate took shape around questions of whether the international system is state-centric or multi-actor and whether cooperation is possible within an anarchic system.

Neo-Realism (Structural Realism)

Introduced by Kenneth Waltz in 1979, Neo-Realism (Structural Realism) departed from classical realism’s state-centric approach by focusing on the structure of the international system. According to Waltz, the fundamental determinant of international relations is not the domestic politics of states but the anarchic nature of the international system itself. The core arguments of neo-realism are as follows:

International System and Anarchy

According to neo-realism, the international system is anarchic and lacks a central authority. States must ensure their own security to survive. This situation leads power balancing and military capacity to become the most important determinants. Kenneth Waltz argued that in an anarchic international system, the primary goal of states is survival, which can only be achieved by maximizing their military power.

States’ Pursuit of Power for Security

Unlike classical realism’s claim that states are inherently aggressive, neo-realism argues that states are not naturally aggressive but are compelled to increase their power due to insecurity in an anarchic system. According to Waltz, state behavior is determined not by domestic politics but by the structure of the system. For example, the rivalry between Cold War and the USSR during the USA era stemmed not from individual state ideologies but from the bipolar structure of the international system.

Hegemony and Cooperation

Neo-Realism argues that international cooperation is possible only when imposed by a hegemonic power. A strong state (hegemon) can compel other states to cooperate and thereby maintain international order.

Example: The United States’ establishment of the Bretton Woods System after World War II to ensure economic stability is an example of the neo-realist hegemony concept.

Neo-Liberalism

Neo-Liberalism, while preserving some assumptions of classical liberalism, challenged neo-realism by arguing that international cooperation is possible even within anarchy. Robert Keohane and Joseph Nye asserted that international relations are shaped not only by power competition but also by economic, social, and institutional interactions. The core arguments of neo-liberalism are as follows:

Interdependence and Transnational Relations

Neo-liberals view international relations as a multi-layered building resembling a spider’s web. They argue that states cannot determine all international processes alone and that actors such as multinational corporations, international organizations, and civil society society organizations are also influential.

Joseph Nye and Robert Keohane argued that as mutual interdependence increases, states become economically dependent on each other, thereby reducing the likelihood of war.

Example: The Europe Union is a strong example of the institutional cooperation model advocated by neo-liberalism.

Anarchy Does Not Prevent Cooperation

According to neo-liberals, even though the international system is anarchic, states can still cooperate. International organizations and agreements can assist states in resolving their security problems.

Robert Keohane’s work After Hegemony demonstrated that international cooperation continues even after the decline of hegemonic power.

Neo-Realism vs. Neo-Liberalism Debate

The debate between neo-realism and neo-liberalism revolved around the question of what constitutes the fundamental determinant of the international system.

• Neo-realists place the anarchic structure of the international system and states’ struggle for power at the center,
• Neo-liberals argue that economic interdependence, institutional structures, and cooperation are also influential in shaping the system.

State-Centrism vs. Multi-Actor System

• Neo-Realism: States are the primary actors in international relations, and security is paramount.
• Neo-Liberalism: In addition to states, multinational corporations, international organizations, and civil society organizations are also decisive actors in international relations.

Possibility of Cooperation

• Neo-Realists: Cooperation is possible only when imposed by a hegemonic power.
• Neo-Liberals: Cooperation is possible through international organizations and economic interdependence.

Impact of the Third Great Debate

The debate between neo-realism and neo-liberalism had a significant impact on the discipline of international relations and increased theoretical diversity.

• Neo-Realism continued to influence analyses of security and power competition,
• Neo-Liberalism emphasized the importance of international organizations, economic relations, and globalization.

As a result of this debate, international relations theories moved beyond being solely state-centric, incorporating economic, social, and institutional factors into their analyses.

Fourth Great Debate: Positivism and Post-Positivism (1990–2016)

The fourth great debate in the discipline of international relations took shape around positivism and post-positivism and began to exert influence from the mid-1980s. The end of the Cold War, the effects of globalization, and transformations in world politics were decisive in its emergence, leading to the necessity of greater discussion within international relations of issues such as Environment problems, human rights, identity, cultural factors, gender, migration, language, information, and power relations. At this point, post-positivism presented a frame that expanded the boundaries of the discipline and developed alternative theoretical approaches.

Positivism and International Relations

Positivism is an approach that considers the scientific method the only valid means of producing knowledge. First used by Saint Simon and later systematized as a philosophical movement by Auguste Comte, positivism was also known as logical positivism and neopositivism in the early twentieth century alongside the Vienna Circle.

The positivist approach in international relations, grounded in Enlightenment thought, argues that knowledge can be produced in an objective and neutral manner. Positivists assert that politics constitutes a distinct structure separate from other fields and that the modern state should be the primary unit of analysis.

Traditional international relations theories such as realism, liberalism, behavioralism, and Marxism are considered positivist approaches. Neorealism and neoliberalism, as rationalist theories, argue that positivist knowledge should serve as the foundation of international relations studies. The core assumptions of positivism are as follows:

• Reality is objective and independent: Reality consists of observable and measurable phenomena.
• The scientific method is the only valid means of knowledge production: Scientific knowledge is based on hypotheses tested through experimentation and observation.
• The state is the primary actor: The state must be accepted as the unit of analysis in international relations, and it must be assumed to be a rational actor.
• Generalization and law formation: Specific laws can be developed in international relations and used to explain events.

Positivist understanding, alongside behavioralism, facilitated the widespread adoption of quantitative methods (statistical analysis, data modeling, game theory, etc.) in international relations. However, criticisms of positivism from the 1980s onward laid the groundwork for the rise of post-positivist theories.

Post-Positivism and the Rise of Critical Theories

Post-positivist approaches, challenging positivism, argue that the discipline of international relations cannot be studied solely through state-centric and quantitative methods. Post-positivist theories encompass a broad framework incorporating various intellectual currents such as critical theory, poststructuralism, postcolonialism, feminism, green politics, and post-modernism.

Post-positivists expanded the scope of the discipline by developing new methods and concepts for analyzing international relations. Concepts such as Discourse analysis, deconstruction, genealogy, power-knowledge relations have increasingly gained prominence in the study of international relations. Post-positivists argue that state-centered narratives, the modern subject concept, European moral codes, and Western lifestyles have been granted privileged positions and must be critically examined.

Main Features of the Positivism–Post-Positivism Debate

The fundamental differences between positivism and post-positivism can be summarized as follows:

Within this framework, positivist approaches use rational actor models and system-level analysis to study international relations, while post-positivist approaches analyze international relations through discourse, identity, and cultural dynamics.

Post-Positivist Approaches

Post-positivist theories have introduced new perspectives to the discipline of international relations:

• Critical Theory: Influenced by the Frankfurt School, it emphasized the repressive structures within the international system. Jürgen Habermas’s normative theory made significant contributions to this approach.

• Poststructuralism: Drawing on the works of Michel Foucault and Jacques Derrida, it critiqued discourses and power relations in international relations.

• Postcolonialism: Rejected Western-centered understandings of international relations and examined the impact of colonial history on global politics.

• Feminism: Analyzed how gender roles are constructed within the discipline of international relations.

• Green Politics: Addressed global environmental issues within international relations and emphasized ecological sustainability.

New Dimensions of the Debate: Rationalists and Constructivists

With the end of the Cold War, the positivism–post-positivism debate continued along two new axes:

• Rationalists and Constructivists: Rationalists such as neorealists and neoliberalists continued to emphasize states’ interest- and power-driven behavior, while constructivists argued that the international system is socially constructed and that states are shaped by identities and norms.

• Constructivism and Critical Theory: While constructivism shares some ideas with critical theory, it adopts a more measurable and scientific approach, distancing itself from postmodern theories.

The positivism–post-positivism debate is a methodological and epistemological cleavage conducted around critical questions of how knowledge is acquired in international relations, whether the state is the primary actor, and how international relations should be studied. Positivists treat international relations as an empirical and measurable science, while post-positivists have developed alternative analytical methods centered on the subjectivity of knowledge, identities, and discourse.

This debate continues today and remains decisive in addressing new issues such as globalization, climate change, migration, and technology, where differences between positivist and post-positivist approaches remain significant.