Classical Realism and Neorealism in International Relations: Conceptual Dissonances and Theoretical Continuities
Realism, as one of the oldest and most enduring traditions in the study of International Relations (IR), offers a coherent framework for understanding the anarchic nature of the international system and the primacy of power in state behavior. Within this broader school, however, critical internal divergences have emerged—most notably between classical realism, rooted in normative-philosophical traditions, and neorealism, or structural realism, which seeks to provide a more scientific and systemic account of international politics.
This essay critically examines the major points of contention between classical and modern (structural/neorealist) variants of realism, while also assessing the conceptual continuities that persist despite these divergences. It contends that while the two paradigms differ sharply in ontological priorities, explanatory mechanisms, and methodological orientation, they remain conceptually tethered by shared assumptions regarding anarchy, self-help, statism, and the centrality of power in shaping international outcomes.
I. Ontological and Epistemological Divergences
A. Human Nature vs. System Structure
A defining point of divergence lies in the respective sources of conflict and power-seeking behavior. Classical realism—exemplified by Hans J. Morgenthau—locates the origins of international conflict in human nature, particularly the inherently self-interested and power-maximizing impulses of political leaders. Morgenthau’s dictum that “international politics, like all politics, is a struggle for power” is grounded in a tragic view of human nature, drawing from thinkers like Thucydides, Hobbes, and Machiavelli.
In contrast, Kenneth Waltz, the progenitor of neorealism in Theory of International Politics (1979), displaces human nature as an explanatory variable and instead attributes the recurrence of conflict to the anarchic structure of the international system. States are compelled to behave in certain ways not because of innate aggression, but because systemic imperatives—such as the absence of central authority and the distribution of capabilities—push them toward self-help and power accumulation for survival.
B. Scientific Rigor vs. Normative Insight
Another major distinction lies in the methodological orientation of each school. Classical realists adopt a philosophical and normative approach, often blending historical interpretation, ethical reflection, and prudential judgment. Their method is largely interpretivist, emphasizing contextual nuance, statecraft, and moral ambiguity.
Neorealists, in contrast, pursue scientific parsimony and predictive power, aligning with positivist epistemology. Waltz aimed to construct a theory with law-like regularities, modeled after microeconomic theories, where states are seen as rational, unitary actors whose behavior can be generalized through systemic analysis. This shift marks a clear departure from the classical emphasis on agential variance and moral complexity.
II. Conceptual and Theoretical Disagreements
A. Balance of Power: Practice vs. Mechanism
Both traditions emphasize the balance of power as a central feature of international politics, but they conceptualize it differently.
Classical realists view balancing as a prudential act of statesmanship—a contingent process mediated by decision-makers, diplomatic acumen, and moral judgment. For Morgenthau, effective balancing depends on political wisdom and the capacity to accommodate shifting interests without provoking systemic collapse.
Neorealists, by contrast, treat balancing as a systemic outcome—an impersonal process that arises mechanically from the pressures of anarchy. States do not necessarily “choose” to balance; rather, they are compelled to do so to preserve their relative position and ensure survival. Waltzian structural realism thus tends to abstract away from foreign policy and agency, focusing instead on system-wide regularities.
B. Role of Ethics and Political Morality
Classical realists incorporate ethical considerations within the realpolitik framework. While deeply skeptical of utopianism, they argue that prudence and moderation are essential to political order. Morgenthau, for instance, insisted that while power is central, its pursuit must be tempered by an awareness of political responsibility and the tragic limitations of human action.
Structural realism, however, is ethically agnostic. Its emphasis on system constraints leaves little room for normative reasoning or moral judgment. Waltz famously argued that the theory of international politics is not concerned with what ought to be but with what is, thereby excluding ethical variables from its analytical schema.
C. State Behavior and Foreign Policy
For classical realists, domestic politics, leadership traits, and national character play a critical role in shaping foreign policy. Thucydides’ analysis of Athens and Sparta, or Morgenthau’s engagement with Weimar Germany and the Versailles Treaty, underscores the importance of historical specificity and political psychology.
Neorealists, by contrast, view states as black boxes—functionally similar units responding to structural incentives. Internal characteristics are largely irrelevant in explaining behavior under anarchy. This renders neorealism poorly equipped to analyze foreign policy variation, a criticism advanced by scholars like Robert Jervis and Fareed Zakaria, who developed neoclassical realism as a synthesis of systemic and unit-level analysis.
III. Conceptual Continuities and Enduring Realist Premises
Despite the aforementioned divergences, classical and neorealist traditions exhibit significant conceptual continuity, which sustains their collective identity under the realist umbrella.
A. Anarchy and the Self-Help System
Both classical realists and neorealists begin from the assumption of anarchy—the absence of a central authority in the international system. This condition generates insecurity, compelling states to rely on self-help mechanisms for survival. Whether derived from human aggression or systemic necessity, both traditions converge on the idea that power competition and conflict are endemic to the international system.
B. Statism and Rational Calculation
Realists across both traditions view the state as the primary actor in international politics. While classical realists attend more to the moral burdens and domestic attributes of states, both camps ultimately treat them as rational actors pursuing national interest—typically defined in terms of power, security, or survival.
C. Skepticism Toward Liberal Norms
Both classical and structural realists exhibit profound skepticism toward liberal institutionalism, idealism, and cosmopolitan visions of perpetual peace. They reject the notion that international institutions or moral norms can fundamentally alter the logic of competition under anarchy, emphasizing instead the recurrence of war, the fragility of alliances, and the limitations of international law.
IV. Synthesis and Contemporary Relevance
In contemporary IR scholarship, the distinctions between classical and structural realism remain significant, particularly in debates over agency vs. structure, ethics vs. scientific neutrality, and the unit-level vs. systemic causation.
However, recent developments have prompted hybrid approaches, such as:
- Neoclassical realism, which reincorporates domestic politics and leadership analysis within a structural framework.
- Constructivist realism, which examines how realist assumptions are socially constructed and historically contingent.
Moreover, realists of all stripes continue to engage with contemporary challenges—from power transitions and multipolarity to the resurgence of great power competition—reaffirming the durability of realism as a pluralist and adaptive tradition in IR theory.
Conclusion
The internal fissures between classical realism and neorealism reflect deeper tensions between humanistic interpretation and scientific abstraction, between moral prudence and structural determinism. While neorealism reorients realism toward systemic explanation, it does so at the cost of normative depth and empirical richness. Classical realism, by contrast, retains a more holistic vision of politics, grounded in history, ethics, and judgment.
Yet, their shared commitment to power, anarchy, and the primacy of the state sustains their coherence as realist paradigms. The tension between them is less a disjuncture than a productive dialectic—one that continues to shape realist thought and its capacity to interpret the ever-evolving landscape of international relations.
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