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International Relations (IR) as a subfield of political science has been shaped by a persistent tension: does world politics ultimately turn on the struggle for power, on the possibility of cooperation, or on deeper structures of inequality and identity? Each major framework emerged to address this question, often by challenging the assumptions of its predecessors. The result is a field that has moved from a narrow, Eurocentric debate between two camps to a pluralistic landscape where multiple traditions coexist, compete, and sometimes borrow from one another.
IR’s first self-conscious framework was Liberalism, which after World War I placed its faith in international law, democratic governance, and institutions such as the League of Nations. Liberals argued that states could overcome the security dilemma through trade, diplomacy, and shared norms. This optimistic vision was soon challenged by Classical Realism, which superseded Liberalism in the aftermath of World War II. Thinkers like Hans Morgenthau insisted that politics is governed by objective laws rooted in human nature; states pursue power because it is in their nature to do so. For realists, the anarchic international system makes conflict inevitable and cooperation fragile.
Between these poles, the English School carved out a middle ground. It accepted realism’s emphasis on anarchy but argued that states also form an international society bound by shared rules and institutions—diplomacy, international law, the balance of power. This framework coexisted with both Liberalism and Classical Realism, offering a more sociological account of state interaction.
Meanwhile, a radical challenge came from the Global South. Dependency Theory, derived from Marxism, rejected the state-centric focus of both Liberalism and Realism. It argued that underdevelopment in the periphery is a direct result of exploitation by the core capitalist states. Dependency theorists shifted attention to economic structures and North–South inequality, a move that mainstream IR largely ignored at the time.
By the 1970s, the Cold War’s bipolar stability prompted a new generation of realists to formalize their assumptions. Neorealism, or structural realism, superseded Classical Realism by locating the cause of state behavior not in human nature but in the anarchic structure of the international system. Kenneth Waltz’s theory treated states as functionally similar units compelled to seek security. Neorealism narrowed realism’s scope, making it more parsimonious and scientific.
At the same time, Neoliberal Institutionalism emerged as a competitor. While accepting neorealism’s assumption of anarchy and rational states, neoliberal institutionalists argued that institutions could reduce uncertainty and facilitate cooperation—even among rivals. The resulting “neo-neo debate” dominated IR in the 1980s. Despite their rivalry, both frameworks shared a rationalist, state-centric ontology and a commitment to positivist methods. They formed a synthesis that defined the mainstream.
Outside this mainstream, Marxism continued as a living tradition, focusing on class conflict and capitalist imperialism. World-Systems Theory, derived from Marxism, broadened the analysis to a single capitalist world-economy divided into core, semi-periphery, and periphery. Immanuel Wallerstein’s framework challenged the state-centrism of both neorealism and neoliberalism by treating the world-system as the primary unit of analysis.
By the late 1980s, dissatisfaction with rationalist frameworks gave rise to a wave of “reflectivist” approaches. Critical Theory, drawing on the Frankfurt School and Antonio Gramsci, reacted against neorealism’s assumption that the existing order is natural. Critical theorists like Robert Cox argued that theory is always for someone and for some purpose; they sought to uncover how power and ideology sustain global inequality and to open space for emancipation.
Poststructuralism went further, rejecting the very possibility of a neutral, objective science of IR. Drawing on Foucault and Derrida, poststructuralists examined how language and discourse construct the realities of sovereignty, anarchy, and security. They deconstructed binary oppositions—inside/outside, self/other—that underpin realist and liberal thought. Where Critical Theory aimed to reform, Poststructuralism aimed to unsettle.
Constructivism offered a more moderate alternative. Reacting against neorealism’s materialism, constructivists like Alexander Wendt argued that anarchy is what states make of it: the identities and interests of states are socially constructed through interaction. Norms, culture, and shared knowledge matter as much as material power. Constructivism absorbed insights from both Critical Theory and Poststructuralism but remained committed to empirical research and dialogue with mainstream IR.
Feminist International Relations emerged in the late 1980s as a distinct critique. Feminists argued that IR’s core concepts—security, sovereignty, the state—are gendered. They exposed how women’s experiences are marginalized and how gender hierarchies shape war, peace, and global political economy. Feminist IR overlapped with Critical Theory and Poststructuralism but maintained its own focus on gender as a category of analysis.
Normative IR Theory also took shape during this period. While Liberalism had always contained normative commitments, normative IR theory explicitly addressed ethical questions about global justice, human rights, and the moral standing of states. It drew on liberal political philosophy but extended it to the international realm, engaging with issues such as humanitarian intervention and global distributive justice.
Since the 1990s, IR has become increasingly pluralistic. Green Theory emerged from environmental movements and ecological thought, challenging the anthropocentrism of all previous frameworks. It argues that environmental degradation and climate change are security issues that cannot be addressed within a state-centric or growth-oriented logic. Green Theory overlaps with Critical Theory and Poststructuralism but insists on the intrinsic value of non-human nature.
Postcolonial International Relations developed as a sustained critique of the Eurocentrism embedded in mainstream IR. Drawing on dependency theory, postcolonial studies, and subaltern perspectives, postcolonial IR scholars argue that the discipline’s concepts—sovereignty, anarchy, development—are products of colonial history. They call for recovering the voices and experiences of the Global South.
Securitization Theory, rooted in the Copenhagen School and influenced by Critical Theory and Poststructuralism, reframed security as a speech act. An issue becomes a security threat not because of objective danger but because a securitizing actor successfully presents it as an existential threat requiring extraordinary measures. This framework shifted attention from material capabilities to the discursive construction of threats.
Global IR is the most recent framework, emerging in 2014 as a call to transform the discipline. It critiques the Western-centric nature of IR theory and advocates for a more inclusive field that draws on non-Western histories, philosophies, and experiences. Global IR does not replace existing frameworks but demands that they be provincialized and supplemented.
Today, no single framework dominates IR. The leading approaches—Neorealism, Neoliberal Institutionalism, Constructivism, Critical Theory, Poststructuralism, Feminist IR, Postcolonial IR, and others—coexist in a state of productive tension. They agree that theory matters and that the world is complex, but they disagree sharply on ontology (material vs. ideational), epistemology (positivist vs. post-positivist), and normative purpose (explanation vs. critique vs. emancipation). The field’s pluralism is itself a subject of debate: some see it as a sign of intellectual vitality, others as fragmentation that hinders cumulative knowledge. What is clear is that IR has moved far beyond its early binary between power and cooperation, and that the frameworks of the future will likely continue to multiply and hybridize.