John J. Mearsheimer and Sebastian Rosato’s How States Think: The Rationality of Foreign Policy (2023) presents a rigorous defense of realism in international relations, arguing that states, regardless of their internal politics or ideological preferences, behave rationally to maximize their security and power.
How States Think: The Rationality of Foreign Policy seeks to counter the perception that states frequently act irrationally due to domestic politics, ideological fanaticism, or leadership mistakes. Instead, the authors claim that states generally pursue a calculated approach to foreign policy based on strategic considerations.
Structural Realism and Power Politics
Mearsheimer and Rosato argue that states, even those perceived as reckless or irrational, tend to act rationally when dealing with international affairs. Leaders make decisions based on a cost-benefit analysis of their security and interests rather than personal ideologies or short-term political gains.
The book reinforces the core tenets of Mearsheimer’s offensive realism: the international system is anarchic, states cannot fully trust each other, and thus they must prioritize survival through power maximization. This power-seeking behavior is not due to greed or ideology but arises from the fundamental structure of international politics.
Contrary to theories that emphasize ideological motivations or the influence of domestic political factions, How States Think asserts that foreign policy is shaped by external pressures rather than internal beliefs. While domestic actors may try to steer a country’s foreign policy, strategic necessity ultimately constrains their options.
Rational Germany in WW1
John J. Mearsheimer and Sebastian Rosato analyze Germany’s decision-making in the First World War through the lens of rational state behavior. They argue that, despite the catastrophic outcome, Germany’s leaders acted rationally given the geopolitical constraints and pressures they faced. Their analysis challenges the notion that Germany was recklessly expansionist or blindly militaristic, instead portraying its decisions as strategic responses to external threats. Germany’s primary security concern before 1914 was encirclement by rival powers, particularly France and Russia, who had formed the Franco-Russian alliance in 1894. The growing military and economic strength of these countries created a long-term threat to Germany’s security. Germany’s leadership rationally calculated that if war was inevitable, it would be better to fight sooner rather than later, while Germany still had a relative military advantage. This aligns with the logic of Preventive War — a key theme in Mearsheimer’s realism.
The German war strategy—the Schlieffen Plan—was designed to avoid a prolonged two-front war by quickly defeating France before turning east to fight Russia. Although the plan ultimately failed, the authors argue that it was not irrational. Given the military and logistical constraints, Germany had limited options and sought to win the war as efficiently as possible. The alternative—fighting a prolonged war on two fronts—was seen as a greater risk, making the plan a rational, if ultimately flawed, strategy.
Germany’s backing of Austria-Hungary in its confrontation with Serbia (after the assassination of Archduke Franz Ferdinand) is often seen as a reckless move that escalated the conflict. However, How States Think argues that Germany had rational reasons to support its ally. If Germany abandoned Austria-Hungary, it risked losing its only strong ally in Europe. Given the rising power of Russia and France, maintaining Austria-Hungary as a counterweight was a strategic necessity.
One of Germany’s most significant mistakes was underestimating Britain’s willingness to intervene. German leaders assumed that Britain would remain neutral or enter the war too late to change its outcome. While this was a miscalculation, the book suggests that it was not irrational—Germany’s leaders based their assumptions on Britain’s past reluctance to commit ground troops to continental wars. They also believed that Britain had no direct territorial stake in the crisis.
In 1917, Germany resumed unrestricted submarine warfare, knowing it would likely provoke U.S. intervention. This decision has been criticized as irrational because it brought a powerful new adversary into the war. However, How States Think presents this as a rational gamble. Germany was desperate to break the British naval blockade, which was crippling its economy and food supplies. German leaders believed they could force Britain to surrender before the U.S. could fully mobilize—another case of rational strategy based on faulty assumptions.
Underestimating, Not Irrational
The book illustrates its arguments using various other historical examples, demonstrating how even seemingly irrational decisions – such as Nazi Germany’s attack on the Soviet Union or the Soviet invasion of Afghanistan – had a strategic logic behind them, even if they ultimately failed. States generally try to act in their best interests but can be led astray by flawed assumptions, intelligence failures, or overconfidence. The authors do find a couple of exceptions to the rule, such as Britain’s failed soft approach against Germany in 1938 and the UK’s misinformed decision to enter the Iraqi War in 2003.
However, when Nazi Germany declared war on the U.S. after Pearl Harbor, it was not compelled to do so under the Axis alliance with Japan. The U.S. had focused its war effort against Japan, and Hitler’s decision ensured that Germany would face a two-front war. This decision is often considered irrational because it greatly accelerated Germany’s downfall. Even if Hitler believed the U.S. would eventually intervene in Europe, he underestimated America’s military and industrial capacity, making this an unnecessary strategic blunder.
The Argentine military junta launched an invasion of the Falklands (Malvinas) in 1982, a British-controlled territory, expecting that the UK would not mount a major military response. However, Britain swiftly deployed a task force and defeated Argentina.
In 1990, Iraq’s Saddam Hussein miscalculated the likelihood of Western intervention and assumed he could annex Kuwait without serious repercussions. His reasoning was based on faulty intelligence and diplomatic misinterpretations. The USSR’s decision to invade Afghanistan led to a prolonged conflict that drained Soviet resources, contributed to internal dissent, and accelerated the decline of the Soviet Union. The Soviets sought to prop up a friendly communist government, but they underestimated the resistance they would face and overestimated their ability to impose stability.
Is Mearsheimer Pro-Moscow?
Mearsheimer has been a controversial figure in international relations debates, particularly for his views on the Ukraine war. He has argued that NATO expansion and Western policies provoked Russia, a stance that critics claim echoes Kremlin talking points. However, his arguments are rooted in the realist tradition rather than ideological sympathy for Moscow.
His perspective on Ukraine is consistent with his broader worldview: major powers seek to maintain spheres of influence, and security concerns drive their actions. From this perspective, Russia’s aggression is not justified but is seen as a predictable reaction to Western policies. This does not necessarily make Mearsheimer “pro-Moscow,” but rather reflective of his longstanding realist framework, which downplays the role of morality and values in international relations. However, one can argue that his rigid focus on structural realism leads to an overly deterministic view, minimizing the agency of smaller states like Ukraine. Furthermore, his assessments often downplay internal Russian decision-making factors, such as Putin’s authoritarianism and ideological motives, which also shape Russian foreign policy.
Too Rational?
How States Think is a thought-provoking and intellectually rigorous book that defends the rationality of state behavior in an unpredictable world. While its arguments are compelling, they can also appear overly deterministic, underestimating the role of ideology, domestic politics, and miscalculation.
Mearsheimer’s work continues to generate debate, particularly in light of current geopolitical conflicts. Whether one agrees or disagrees with his views, How States Think offers a valuable lens for understanding how states navigate the complex arena of international politics.
