John J. Mearsheimer and Sebastian Rosato write in this 2023 book:
* Contrary to what many people think, we cannot equate rationality with success and
nonrationality with failure. Rationality is not about outcomes. Rational actors often fail to achieve their goals, not because of foolish thinking but because of factors they can neither anticipate nor control. There is also a powerful tendency to equate rationality with morality since both qualities are thought to be features of enlightened thinking. But that too is a mistake. Rational policies can violate widely accepted standards of conduct and may even be murderously unjust.
* Rationality is all about making sense of the world for the purpose of navigating it in the pursuit of desired goals… Rational decision makers are theory-driven—they employ credible theories both to understand the situation at hand and to decide the best policies for achieving their objectives. A state is rational if the views of its key decision makers are aggregated through a deliberative process and the final policy is based on a credible theory. Conversely, a state is nonrational if it does not base its strategy on a credible theory, does not deliberate, or both. A careful review of the historical record shows that judged by these criteria, states are regularly rational in their foreign policy.
* Rational policymakers are theory-driven; they are homo theoreticus. They have
credible theories—logical explanations based on realistic assumptions and supported by substantial evidence—about the workings of the international system, and they employ these to understand their situation and determine how best to navigate it. Rational states aggregate the views of key policymakers through a deliberative process, one marked by robust and uninhibited debate. In sum, rational decisions in international politics rest on credible theories about how the world works and emerge from a deliberative decision-making process.
All of this means that Russia’s decision to invade Ukraine was rational.
* Individuals have in their heads different theories—probabilistic statements made up of assumptions, causal logics, and supporting evidence—about various aspects of international politics. Many of these The Rational Actor Assumption theories are credible, which is to say their assumptions are realistic, their causal stories are logically consistent, and their claims find substantial support in the historical record. Some theories, however, are noncredible on suppositional, logical, or empirical grounds (or all three), in which case the policy prescriptions that flow from them are nonrational. So, too, are strategies based on any form of nontheoretical
thinking.
When confronted with the need to make a decision on a particular issue, rational policymakers once again rely on credible theories. Because they explain the way the world works, these theories help policymakers decide the best strategy for dealing with the situation at hand. To be sure, no credible theory applies to all problems,
and even if it applies in one instance, it may not do so later if circumstances change. In other words, rational policymakers are strongly wedded to their theories, but they also assess whether those theories apply in the relevant case, and they are willing to change their minds in the face of powerful new evidence.
* Theories are simplified descriptions of reality that explain how some facet of the world works. They are made up of empirical claims, assumptions, and causal logics. Empirical claims in the international relations literature stipulate a robust, though not absolute, relationship between an independent and a dependent variable.
* Policymakers’ reliance on theories is unsurprising, as it is the only viable way they can do business.
* Binyamin Appelbaum writes in The Economists’ Hour, an account of the relationship between economic theories and American economic policy between 1969 and 2008, that Richard Nixon “was not well versed in economics but, like most Americans of his generation, his basic frame of reference was Keynesianism. He believed the government faced a choice between inflation and unemployment, and he knew what he wanted to order from the menu.” Ronald Reagan, by contrast, was heavily influenced by Milton Friedman’s monetarist theories, going so far as to write a leading journalist that he could not embrace a policy proposal that “one of my favorite people Milton F. opposed.” More generally, Appelbaum makes it clear that the evolution of American
economic policy over the decades he covers was influenced at every turn by competing theories.14
Much like its economic policy, America’s foreign policy since the Cold War has relied on the same theories that populate academia. The United States adopted a policy of liberal hegemony after the superpower competition ended and the world became unipolar.
That policy was based on the “big three” liberal theories of international relations: liberal institutionalism, economic interdependence theory, and democratic peace theory.
* Policymakers’ reliance on theories is unsurprising, as it is the only viable way they can do business. The essence of policymaking is determining the consequences of different strategies.
* Realist theories share the premise that the architecture of the international system is the main driver of state behavior. “Realism,” Kevin Narizny notes, “is a top-down paradigm. Every realist theory must start with a specification of systemic imperatives; only then can it address other factors.”
Liberalism, Narizny writes, “‘rests on a ‘bottom-up’ view of politics in which the demands of individuals and societal groups are treated as analytically prior to politics.’ Every liberal theory must start with a specification of societal actors and their preferences; only then can it address other factors.”
* A rich tradition, with both philosophical and religious roots, mandates that states should aim to avoid killing civilians while waging war. This line of thinking is especially powerful in liberal democracies, where it is widely believed that human rights are inalienable and directly targeting noncombatants is therefore an atrocity.
Yet the historical record shows that when states believe their survival is at stake, they do not hesitate to kill large numbers of civilians if such murderous behavior will help them avoid defeat or massive casualties on the battlefield. Britain and the United States blockaded Germany during World War I in an attempt to starve its civilian population and force the Kaiserreich to surrender. The United States also relentlessly firebombed Japanese cities beginning in March 1945 before dropping atomic weapons on Hiroshima and Nagasaki in August, to bring World War II to an end and minimize American casualties.
