How do realist theories conceptualize the strategies states must adopt to survive in an anarchical international system?

Realist theories in international relations, rooted in foundational works such as Hans Morgenthau’s Politics Among Nations (1948) and Kenneth Waltz’s Theory of International Politics (1979), conceptualize the international system as fundamentally anarchical, meaning that there is no overarching authority above sovereign states to enforce rules or guarantee security. In this environment, states are the primary actors, and survival — understood as maintaining sovereignty and territorial integrity — becomes the core national interest guiding their behavior. Realist approaches offer a range of conceptualizations regarding the strategies states must adopt to survive under anarchy, though they share key underlying assumptions: the centrality of power, the prevalence of self-help, and the ever-present possibility of conflict.

Structural realists, particularly Waltz, argue that the distribution of material capabilities — or the balance of power — shapes state strategies. According to Waltz’s neorealism, states have no choice but to operate within the constraints imposed by systemic anarchy, where the absence of hierarchy compels them to prioritize relative power over absolute gains. The key strategies emphasized here are balancing and internal development. States may engage in internal balancing by investing in military buildup, technological advancement, and economic resilience to strengthen their position vis-à-vis potential rivals. Alternatively, they may practice external balancing by forming alliances to counterbalance more powerful states or coalitions. Waltz argues that balancing behavior tends to be more stable in a bipolar system, where two dominant powers check each other, than in multipolar systems, where alliance shifts are more fluid and potentially destabilizing.

Offensive realism, advanced by John Mearsheimer in The Tragedy of Great Power Politics (2001), offers a more aggressive interpretation of state behavior. Mearsheimer contends that because states can never be certain of others’ intentions and because power maximization enhances security, the rational strategy for states is to seek regional hegemony and maximize their relative power whenever possible. Rather than merely balancing or deterring, offensive realism envisions a world where great powers continually look for opportunities to expand influence, weaken rivals, and prevent the emergence of peer competitors. This leads to a fundamentally conflictual and competitive strategic environment, where even status quo powers are compelled to act offensively to secure their survival.

Defensive realism, in contrast, emphasizes that overexpansion can provoke counterbalancing and increase insecurity. Scholars like Stephen Walt and Robert Jervis argue that under certain conditions, restraint, status quo maintenance, and defensive postures are more effective for survival. Here, the concept of the security dilemma is central: efforts by one state to increase its security (e.g., military buildup) can inadvertently threaten others, triggering an arms race or escalation spiral, even when no party desires conflict. Defensive realism suggests that careful signaling, defensive military doctrines, and the establishment of credible security guarantees can help mitigate these risks.

Classical realism, rooted in the writings of Morgenthau, emphasizes the role of human nature, prudence, and the ethical dimension of statecraft. While structural realists focus on the impersonal constraints of anarchy, classical realists highlight the importance of wise leadership, diplomatic skill, and political judgment in navigating power politics. For Morgenthau, survival is not merely a mechanical response to systemic pressures but requires the prudent balancing of power and morality, avoiding both reckless adventurism and naïve idealism.

Realist strategies also incorporate alliances, deterrence, and balancing commitments. Alliances are seen as temporary marriages of convenience, shaped by shifting threat perceptions rather than shared values or institutions. Deterrence, especially in the nuclear era, becomes a key strategic practice, relying on credible threats to prevent adversaries from attacking. Realists are generally skeptical of the durability of collective security systems or international institutions, viewing them as secondary to the hard realities of material power and strategic necessity.

In sum, realist theories conceptualize survival strategies as revolving around power maximization, balancing, deterrence, alliance formation, and prudent statecraft, all within a system where uncertainty, insecurity, and competition are permanent features. Whether emphasizing defensive caution or offensive expansion, realists converge on the belief that under anarchy, states must rely primarily on their own capabilities and strategic choices, not on external guarantees or moral appeals, to ensure their continued existence.