John Mearsheimer

Mearsheimer's master claim in *The Tragedy of Great Power Politics* (Mearsheimer 2001; DOI 10.5860/choice.39-5464; reissued/updated editions) is that the international system's structure compels great powers to pursue power maximization, not mere security sufficiency. Five bedrock assumptions - anarchy (no night-watchman above states), states possess offensive military capability, intentions can never be known with certainty, survival is the primary goal, and states are rational actors - combine to make the *only* rational posture the relentless accumulation of relative power. Unlike defensive realists, who argue that states seek an "appropriate amount" of power, Mearsheimer holds that the system rewards the strong and punishes the weak, so a prudent great power keeps maximizing until it achieves hegemony (Toft 2005, "John J. Mearsheimer: an offensive realist between geopolitics and power," DOI 10.1057/palgrave.jird.1800065).

Because oceans make global conquest impossible to sustain, Mearsheimer argues the achievable strategic goal is *regional* hegemony, after which a state acts as an "offshore balancer" to prevent peer competitors from dominating other regions. The United States is his paradigmatic regional hegemon. The argument is developed historically in his account of America's continental rise (Layne and related offensive-realist extensions, e.g. "Extending Offensive Realism: The Louisiana Purchase and America's Rise to Regional Hegemony," 2004, DOI 10.1017/s0003055404041358).

The "tragedy" in Mearsheimer's title is that even status-quo states cannot escape competition: because intentions are unknowable and capability is observable, one state's defensive build-up reads as another's threat, producing arms racing and conflict that nobody strictly wants. Cooperation is possible but thin and always shadowed by relative-gains concerns and the fear of cheating.

In "The False Promise of International Institutions" and the surrounding corpus (Mearsheimer's enduring critique; see also "The Politics, Power, and Pathologies of International Organizations," 1999, DOI 10.1162/002081899551048, which formalizes why IOs are agents of state power rather than autonomous constrainers), institutions are epiphenomenal: they reflect the distribution of power and the self-interested calculations of the most powerful states, and cannot by themselves cause peace or override the security imperative. Where realism and liberal-institutionalism diverge, Mearsheimer bets that power, not rules, predicts outcomes.

Mearsheimer's applied corollary - most visible in his China writings and his "can China rise peacefully?" thesis - is that a rising China will seek regional hegemony in Asia exactly as the US did in the Western Hemisphere, and the US will balance hard against it, making intense security competition (and risk of war) the default expectation. The framework is explicitly predictive and is repeatedly tested in the power-transition literature (recent extensions: "Great power competition, offensive realism, and the new debates on US grand strategy," 2025, DOI 10.1080/01495933.2024.2445492; "Power Transition, Offensive Realism and the Emerging U.S.-China rivalry," 2026, DOI 10.36948/ijfmr.2026.v08i02.75825).

orbit is a near-pure test case for offensive realism. It is anarchic (no enforcer), capability is dual-use and offensively potent (any maneuverable satellite or ground laser is a latent weapon), intentions are radically opaque (you cannot read a satellite's purpose from its orbit), survival of critical space infrastructure is existential for modern militaries and economies, and the actors - the US, China, Russia - are exactly the great powers Mearsheimer models. His frameworks predict where space cooperation will fail, why an arms race is structurally likely, and why institutional fixes (treaties, codes of conduct) will track the power balance rather than constrain it.