The Rarity of Realpolitik: What Bismarck's Rationality Reveals about International Politics

Realpolitik, the pursuit of vital state interests in a dangerous world that constrains state behavior, is at the heart of realist theory. All realists assume that states act in such a manner or, at the very least, are highly incentivized to do so by the structure of the international system, whether it be its anarchic character or the presence of other similarly self-interested states. Often overlooked, however, is that Realpolitik has important psychological preconditions. Classical realists note that Realpolitik presupposes rational thinking, which, they argue, should not be taken for granted. Some leaders act more rationally than others because they think more rationally than others. Hans Morgenthau, perhaps the most famous classical realist of all, goes as far as to suggest that rationality, and therefore Realpolitik, is the exception rather than the rule.¹ Realpolitik is rare, which is why classical realists devote as much attention to prescribing as they do to explaining foreign policy.

Is Realpolitik actually rare empirically, and if so, what are the implications for scholars' and practitioners' understanding of foreign policy and the nature of international relations more generally? The necessity of a particular psychology for Realpolitik, one based on rational thinking, has never been explicitly tested. Realists such as Morgenthau typically rely on sweeping and unverified assumptions, and the relative frequency of realist leaders is difficult to establish empirically.

In this article, I show that research in cognitive psychology provides a strong foundation for the classical realist claim that rationality is a demanding cognitive standard that few leaders meet. Rational thinking requires objectivity and deliberation. Human beings, however, tend to see the world through a subjective lens and use decisionmaking shortcuts rather than engage in careful analysis. Cognitive psychology research also shows that rational thinking varies across individuals. Some are more objective and deliberative than others. If Realpolitik depends on rational thinking, then it should not be taken for granted. Rationality will be confined to a relatively small set of leaders with a particular set of individual psychological characteristics.

To support my argument that rationality is rare and Realpolitik the exception in foreign policy, I consider a case in which Realpolitik should be particularly common among foreign policy practitioners: Prussia before German unification. The weakest of the great powers at the time, it was surrounded by potential enemies and geographically vulnerable. In other words, Prussia's external environment highly incentivized rationalist thinking and rational behavior.

Guiding Prussian foreign policy in this period was Otto von Bismarck, perhaps the most famous realist practitioner of all time. Rather than sharing the views of his conservative peers, however, Bismarck was an outlier in his own country, distinguished largely by his cognitive psychological style. Bismarck was highly objective and deliberative. Even though other leaders faced the same international pressures and constraints, support for Realpolitik, rather than pervasive, was exceedingly rare. Indeed, virtually no major figure in either Prussian or, after unification, German politics shared Bismarck's views on foreign affairs, even fellow conservatives.

The conclusion is that the greatest realist statesman of his era, perhaps world history, was a historical anomaly. When explaining how international politics works, realist scholars often make reference to the great realist practitioners, such as Bismarck, and their successes.² But in so doing, they inadvertently highlight the relative infrequency of Realpolitik. The “great men” (which of course could just as easily include women) are great because of their exceptionality. This observation has profound implications both theoretically and prescriptively. By one logic, if realist claims about the nature of international politics are accurate, then the practice of Realpolitik should be common. If Realpolitik is more exceptional than commonplace, however, scholars and practitioners might think very differently about international relations. Realist predictions of foreign policy practice should be limited to those instances in which state leaders possess the psychological attributes conducive to Realpolitik: a commitment to objectivity and deliberation.

In the sections that follow, I first develop a working definition of Realpolitik based on a review of both classical and structural realist scholarship. Realist theory rarely explicitly defines the construct. Nevertheless, I argue that broad agreement exists, at least implicitly, that Realpolitik is the pursuit of egoistic (i.e., exclusively self-interested) state interests in light of largely material structural constraints. In other words, Realpolitik is what is referred to in the academic literature as “instrumental” rationality—that is, doing the best one can for one's country in a given situation. All realists seem to agree that the nature of international politics incentivizes such rationality, although they might disagree about how much the international environment constrains state action, and therefore how much Realpolitik to expect.³

Drawing on classical realist scholarship, I then argue that Realpolitik requires “procedural” rationality, the process of rational thinking, whose main hallmark is a commitment to objectivity and deliberation. Classical realists have long claimed that the pursuit of Realpolitik requires a particular psychology, one that should not be taken for granted. Scholars often forget the intensely cognitive and prescriptive nature of classical realist thought—only those who think rationally will act like realists; many do not and more should.

The third section connects these traditional insights to the literature on cognitive psychology, which confirms that rationality varies across individuals and that rational thought is a particularly demanding normative benchmark that only few approach. Some individuals have more “epistemic motivation,” a commitment to rational thought. This psychological literature therefore provides a stronger empirical basis for classical realist claims about rationality. Combined with an egoistic orientation, rational thinkers are likely to behave as realists expect: maximizing state interests in light of constraints. If leaders do not objectively observe their environment and deliberate over its nature, they cannot respond to it. And if they are not pursuing egoistic gains for their states, they do not have the incentive to do so. As rationality is a matter of degree, however, few leaders meet those exacting standards. I identify how self-interest and rational thinking combine to generate familiar foreign policy tendencies such as strategic understanding and long-term orientations.

In the fourth section, I explain why the Bismarck case is so informative. If Realpolitik is prevalent where systemic constraints are the greatest, then nineteenth-century Prussia should have been overflowing with realists. I then outline Bismarck's realism. Bismarck was both egoistically Prussian and a rational thinker with high levels of epistemic motivation, which in turn made him highly consequentialist and instrumentally rational in his foreign policy approach. Although Bismarck's realism is well known, I show that it was predicated on a psychological commitment to objectivity and deliberation.

I then contrast Bismarck with his conservative allies, who were both less egoistic and less epistemically motivated. In bringing about unification, Bismarck had to fight against so-called romantic conservatives, who were willing to sacrifice Prussian interests to transnational legitimist solidarity in the fight against liberalism. They had a less exclusively self-interested approach to foreign policy. Most important, they resisted war against the Austrian Empire, which Bismarck viewed as necessary to exclude the Habsburgs from the Germanic sphere and create a new unified German state. Even when conservatives shared his goals, however, their very different cognitive styles led them to radically different conclusions about the proper course to pursue. A rational and therefore consequentialist thinker, Bismarck was willing to accept certain lesser evils that other conservatives would not—in particular, distasteful alliances with ideological foes such as revolutionary France and German liberal nationalists. He was a rarity in Prussian politics.

Bismarck drove Prussia into a war with Austria over the initial objections of his conservative patrons. Following Prussia's early victories, however, Bismarck had to struggle to contain these same conservatives' efforts to pursue aggrandizement against the Habsburgs, which Bismarck believed would ultimately weaken rather than strengthen Prussia. He advocated a policy of strategic restraint, pragmatically accepting the more limited gains that would lay the foundation for a unified Germany and set the scene for the eventual incorporation of all the smaller German states. This episode shows that the difference between Bismarck and his colleagues does not reduce to alternative conceptions of Prussian interests. Bismarck's efforts to restrain Prussia's king, Wilhelm I, demonstrate a contrast between a deliberate, careful, and sober (in other words, rational) statesman and an impulsive, shortsighted, and emotional sovereign. Bismarck was both more and less expansionist than his compatriots, depending on the situation. As a more rational thinker, he adjusted Prussian aims to the constraints of the moment in a way they did not.

I conclude with the implications of my argument for international relations theory and foreign policy. If I am correct, the ability of realists to offer explanations of foreign policy based on instrumental rationality is severely limited, given that most leaders lack the required state egoism and cognitive style. The argument suggests that neoclassical realism is a more fruitful avenue of academic pursuit. Realpolitik is most likely to mark the foreign policy of rational leaders, and those who practice Realpolitik will be rewarded by the system in a way that less rational thinkers are not. The argument's consequences for realism as a theory of international relations outcomes, as opposed to foreign policy, are less obvious. Is it theoretically possible that the international system can operate on the basis assumed by systemic realists even without instrumentally rational states—that is, without Realpolitik? I argue that a world composed of largely egoistic but nonrational states would be particularly dangerous and constraining, thus making the pursuit of Realpolitik all the more important.

Prescriptively, the argument implies that policymakers should not assume that their counterparts abroad are rational. Realist prescription must take into account the degree to which rational thinking prevails among state leaders. Moreover, policy advocates must recognize that the intended audience for their advice is not necessarily rational and therefore is not predisposed to persuasion by deliberative arguments.

To establish whether Realpolitik is commonplace, we first need a working definition. If Realpolitik is defined too narrowly, then noting its relative infrequency is no feat at all and says little about foreign policy or international relations. The definition should be elastic enough to be uncontroversial, making it acceptable to those working within the many different strains of realism, but also expansive enough to serve as a difficult test for my argument. In particular, we are looking for a conception that is consistent with both classical and structural realism, a common distinction in the literature. While both schools of realism agree that international relations take place in a dangerous environment in which states might need to resort to violence to achieve their objectives, proponents of both schools base this belief on assumptions at different levels of analysis. Classical realists ground their approach in what they see as humans' quest for power; structural realists ground their approach in the uniquely anarchic nature of the system in which nation-states interact.

Conceivably, I could simply look for how prominent realists have defined Realpolitik in their writings and find a common denominator. But although there have been many efforts to define the principles of realism, I find virtually no mention of what constitutes Realpolitik. The historian John Bew concludes that “few satisfactory definitions exist, largely because international-relations theorists have remained uninterested in its historical origins.”⁴ He does not, however, offer his own definition, noting only that understanding of the concept has changed over time so as to suit different political and ideological agendas.

Realpolitik is a German term, first used in the 1850s, whose etymology suggests a way forward.⁵ Crudely translated, Realpolitik means “realistic policy.” So, what policies do realists think that states follow, or, at least, should follow? For the purposes of this article, I define Realpolitik as the egoistic pursuit of the national interest under largely material structural constraints. The definition seems unobjectionable, perhaps even trivial. However, from this spare and simple premise—that states think only of themselves but must operate in a largely unregulated environment where others are doing the same—can be deduced all the other phenomena that have come to be identified with realism, of which two are perhaps most important. First, power is indispensable, and the ultima ratio of military force always lurks in the background.⁶ This does not mean, as is often maintained, that realism is equivalent to militarism or a trigger-happy resort to violence.⁷ Realism is about the smart application of power, which can be (literally) a double-edged sword.⁸ Second, the moral rules of international conduct are different from those that might apply domestically or in interpersonal relations. The dangerous nature of international politics is such that states must look out for themselves first, and this requires that they do things—most notably, use violence—that would be morally unacceptable in other political contexts. It is not that realists have no commitment to principles. On the contrary. Realpolitik is based on an “ethic of responsibility” judged by its outcomes.⁹ Realist ethical judgments are utilitarian and pragmatic, rather than deontological (in which certain rules of conduct are binding regardless of their consequences). Realists therefore expect that states either do not or should not apply typical liberal ethical norms, such as the nonviolent resolution of conflicts, to their international conduct.

There is considerable debate among realists about what constitutes egoistic behavior. Do states seek to maximize power or security?¹⁰ Do they strive to become the dominant power of the system or merely to preserve a modicum of peace? Are they perhaps even driven by other goals, such as honor and status? Despite these differences, realist scholars agree that states are largely self-regarding.¹¹ Some see states as engaging in self-aggrandizement; others see states as engaging only in self-preservation. Regardless, foreign policy is self-centered. Even motivations such as pride are self-regarding. This commonality explains realist resistance to claims that national interests can be constrained by international norms or international organizations.¹²

Claims of state egoism are most common in classical realism, which makes sense given its grounding in assumptions about human nature. Reinhold Niebuhr writes of the “natural egoistic impulse with which all life is endowed.”¹³ Friedrich Meinecke argues, “The well-being of the State and of its population is held to be the ultimate value and the goal.” He continues, “National egoism, the impulse to power and towards self-preservation, that is to say State interest, is timeless and general.”¹⁴ As A.J.H. Murray writes, states cannot consider “cosmopolitan” (i.e., non-egoistic) interests, but must concern themselves only with “national” goals.¹⁵ Nevertheless, assumptions of egoistic state behavior permeate structural realism as well.¹⁶ Survival, generally recognized as the cornerstone of neorealism, is the preservation of the self.

In this way, structural realists do not offer an exclusively systemic theory of international relations, because their arguments rest on generally explicit assumptions about the wants of states. There is no security competition if states are not self-regarding, and the more expansive their egoistic impulses, the more dangerous the international environment.¹⁷ Using as an example the operation of a market, Kenneth Waltz famously argued that systems operate independently of the character of the units.¹⁸ A world of nonprofit providers of goods and services would generate different system dynamics, however. In other words, self-interest on the part of states, an attribute of units, is necessary to generate the systemic pressures of anarchy. As Alexander Wendt has illuminated conceptually, a state system comprising other-regarding units would not generate the dynamics that realists presuppose.¹⁹

Just as all realists assume that states are egoistic, they also make reference to the importance of structural constraints. Unlike neorealists, classical realists refer not to “anarchy,” but to “necessity.”²⁰ Meinecke writes, “Too often … a choice is out of the question … Raison d'état thus takes on the profound and serious character of national necessity.”²¹ He writes of “the environment of the State … This is a situation of constraint in which the State finds itself, in the face of threats either from within or without, and which forces it to adopt defensive and offensive means of a quite specific kind. Today one usually says in such cases that its behavior is ‘constrained.'”²² Similarly, according to E.H. Carr, “The realist analyses a predetermined course of development which he is powerless to change.”²³ Realism “tends to emphasize the irresistible strength of existing forces and the inevitable character of existing tendencies.”²⁴ Morgenthau states, “The realist parts company with other schools of thought before the all-important question of how the contemporary world is to be transformed. The realist is persuaded that this transformation can be achieved only through the workmanlike manipulation of the perennial forces that have shaped the past as they will the future.”²⁵

For many classical realists, the structural constraint was the egoism of other states rather than the absence of a supranational coercive authority.²⁶ Egoism itself, however, cannot logically lead to the power political outcomes that realists believe are ubiquitous without the permissive factor of anarchy.²⁷ A society composed of knaves with a really good police force might be completely peaceful.

The most important constraint in international relations is, of course, the distribution of power. For structural realists, power is called “capability.”²⁸ The term itself is etymologically derivative of “ability,” which implies what can, as opposed to what cannot, be done. Joseph Parent and Joshua Baron observe that for classical realists, just like their contemporary cousins, “structure ruled … behavior was proportionate to power, and … interacting states had various appetites, but appetite was more a function of capability than taste.”²⁹

Thus, for all the important distinctions between the classical and structural realist traditions, each needs the insights of the other to make its approach whole. Classical realism relies (implicitly and sometimes even explicitly) on the permissive cause of anarchy to generate power political dynamics, and structural realism relies (again often implicitly) on an egoistic theory of state motivation rooted in assumptions about the units. Realpolitik brings them together.

The pursuit of egoistic interests in light of structural constraints is the very definition of instrumental rationality.³⁰ States in realist theory behave (or should behave) as consequentialists that weigh costs against benefits, recognizing that one cannot have it all.³¹ They adjust goals in light of the distribution of power and the likely responses of other states. As mentioned before, realism rests on a utilitarian moral logic in which the ends justify the means. Therefore, instrumental rationality, exercised on behalf of the state's interest, is part of the essence of Realpolitik.

The status of the rationality assumption in realist theory is contested, however, dividing structural realists in particular.³² Whereas Waltz argues that his systemic theory does not rest on any assumption of rationally behaving states, other structural realists—most prominently, John Mearsheimer—make rationality an essential element of their structural realist theories and criticize Waltz for failing to do so.³³ The difference, as Mearsheimer himself notes, lies in Waltz's use of an evolutionary model of selection.³⁴ Systems do not determine state policy but rather provide feedback, punishing those that stray from its dictates and rewarding those that act in line with them.³⁵ Systems cannot pull the trigger, literally or figuratively.

In using this systemic logic, Waltz is arguing that the international environment incentivizes instrumental rationality, even if it cannot compel it. As Colin Elman writes, “In the final analysis … Waltz appears to depend on assumptions of rational choice, asserting that statesmen are ‘sensitive to costs' and are likely to respond efficiently to changing international conditions and incentives.”³⁶ Mearsheimer agrees, arguing that for Waltz, “The cost of pursuing misguided policies creates powerful incentives for states to act rationally … Waltz's theory has a baseline embedded in it that explains how states would act if they were rational agents.”³⁷ Therefore, the difference among structural realists concerning instrumental rationality can be overstated. All neorealists agree on the incentives for states to act in an instrumentally rational manner (i.e., practice Realpolitik); differences among them likely can be reduced to the extent that they conceptualize the scarcity of security in the system.³⁸ Offensive realists regard the world as even more dangerous than do defensive realists such as Waltz and, accordingly, adopt tighter assumptions concerning rationality. Threat focuses the mind.

Classical realists seem to be more unified than structural realists concerning the necessity of instrumental rationality in Realpolitik. As Morgenthau writes, “Prudence—the weighing of the consequences of alternative political actions” is “the supreme virtue in politics.”³⁹ Classical realists, however, probe deeper. They claim, implicitly, that instrumental rationality presupposes what Herbert Simon has called “procedural” rationality.⁴⁰ Whereas instrumental rationality is making the best choice possible given the constraints at the time, procedural rationality comprises all of those cognitive processes associated with rational decisionmaking—most importantly, the unbiased analysis of information and careful deliberation. This is rational thought or reason and does not need to be applied to securing egoistic ends, or any ends at all. Scientists study the stars using procedural rationality simply to understand them, not to outmaneuver them in a bargaining setting. But, when procedural rationality is combined with egoism, the result is the strategic and calculating thinking that is essential to Realpolitik. Realists are not telling leaders just what to think; they are telling them how to think.

As mentioned, rational thought has two core components—objectivity and deliberation. Structural constraints have to be perceived, which requires an accurate evaluation of the environment. This is the “real” in real-ism. Alternative courses of action must be considered and judged according to an estimation of their consequences, which requires active deliberation. Realist arguments are as much about cognitive style as they are about empirical substance. Meinecke writes, “For raison d'état demands first and foremost a high degree of rationality and expediency in political conduct.”⁴¹ Morgenthau advises, “In order to eliminate from the political sphere not power politics—which is beyond the ability of any political philosophy or system—but the destructiveness of power politics, rational faculties are needed.”⁴² Jonathan Haslam agrees that “the key goal of the realists in formulating Reason of State was to introduce and enforce the dictates of rationality in decision-making.”⁴³

Objectivity is central. “Political realism wants the photographic picture of the political world to resemble as much as possible its painted portrait,” writes Morgenthau.⁴⁴ Similarly, Carr writes that the realist “will embark on that hard ruthless analysis of reality, which is the hallmark of science.”⁴⁵ Such rationality, however, is not without its problems, nor is it a given, because it requires admitting the painful truth that one cannot have it all. To promote one's interests, one might have to sacrifice one's principles, for instance. The statesman must also separate vital interests from peripheral ones and jettison the latter.⁴⁶ The ends justify the means. One chooses the lesser evil. Morgenthau writes that realism “believes … in the possibility of distinguishing in politics between truth and opinion—between what is true objectively and rationally, supported by evidence and illuminated by reason, and what is only a subjective judgment, divorced from the facts as they are and informed by prejudice and wishful thinking.”⁴⁷ Similarly, Carr writes, “The impact of thinking upon wishing … is commonly called realism. Representing a reaction against the wish dreams … realism is liable to assume a critical and somewhat cynical aspect. In the field of thought, it places its emphasis on the acceptance of facts” that one is “powerless to influence or alter.”⁴⁸

Rational thinking is cold and unemotional.⁴⁹ Realists caution against the passions, as they impede the cognition necessary for Realpolitik. Meinecke writes that the realist “should rule himself strictly that he should suppress his emotions and his personal inclinations and aversions, and completely lose himself in the practical task of securing the common good. He should also seek, quite coolly and rationally, to ascertain the practical interest of the State, and to separate these from any emotional overtones—for hatred and revenge … are bad counsellors in politics.”⁵⁰ Meinecke cautions that “raison d'état demands … an ice-cold temperature.”⁵¹

The realist focus on objectivity and deliberation is deeply psychological. Thinking is a core aspect of Realpolitik, as is evident from the syntax of classical realist texts. “The insight and the wisdom of the statesman gauge accurately the distribution and relative strength of opposing forces and anticipate, however tentatively, the emerging pattern of new constellations,” opines Morgenthau.⁵² Carr distinguishes the “imagination” of the utopian from the realist who operates through “intellectual effort.”⁵³ The “function of thinking is to study a sequence of events which it [one] is powerless to influence or to alter … The highest wisdom lies in accepting and adapting oneself to these forces and these tendencies.”⁵⁴ This is all another way of describing rationality. Carr's Twenty Years' Crisis, perhaps the book most responsible for defining the realist and his antithesis in early international relations theory, was at its heart a book about the cognitive failings of the utopians, for whom Carr claims “wishing prevails over thinking, generalization over observation, and in which little attempt is made at a critical analysis of existing facts or available means … Thought has been at a discount.”⁵⁵

As the above passages indicate, classical realism also has a distinctly normative and prescriptive character.⁵⁶ Not only does Realpolitik require rational thinking, but this cannot be taken for granted. As Morgenthau observes, “Political realism contains not only a theoretical but also a normative element.”⁵⁷ He continues, “Political realism considers a rational foreign policy to be good foreign policy; for only a rational foreign policy minimizes risks and maximizes benefits and hence complies both with the moral precept of prudence and the political requirement of success.”⁵⁸ David Zarnett writes, “Realism is a project that aims to raise awareness of what its proponents see as the ‘reality’ of international politics and to shape state behavior in accordance with that reality. This reality is not comprised of what individuals and states actually do out there but rather of the forces that determine what types of policies will be successful and what types of policies will fail.”⁵⁹ In keeping with this theme, Marc Trachtenberg observes that it is when statesmen act most like realists, “rational in power political terms,” that the international system is most stable.⁶⁰ This outcome, however, is not foreordained, honored oftentimes in the breach and not the observance because of how (and how much) leaders think.

This normative character of realism reveals that realists do not expect Realpolitik at all times. Rather, Realpolitik depends on the dispositional qualities of the state leader. “We cannot conclude from the good intentions of a statesman that his foreign policy will be either morally praiseworthy or politically successful … It stands to reason that not all foreign policies have always followed so rational, objective and unemotional a course. The contingent elements of personality, prejudice and subjective preference, and of all the weaknesses of intellect and will which flesh is heir to, are bound to deflect foreign policies from their rational course,” states Morgenthau.⁶¹ For Meinecke, “the ‘intelligence’ of the State consists in arriving at a proper understanding both of itself and its environment … The statesman must, if he is convinced of the accuracy of his understanding of the situation, act in accordance with it in order to reach his goal … The statesman in power tries hard to discern this course.”⁶² The clear implication is that Realpolitik is a function of the psychology of the leader. Reviews of classical realism concur.⁶³

Morgenthau goes as far as to argue that Realpolitik might even be the exception rather than the rule: “Political realism presents the theoretical construct of a rational foreign policy which experience can never completely achieve.”⁶⁴ He is aware that “actual foreign policy does not or cannot live up to” realist demands.⁶⁵ Indeed, Realpolitik is exceptionally hard given the intense psychological demands of rationality. The statesman has to objectively look those difficult truths in the face.

It is the nature of things that a theory of politics which is based upon such principles will not meet with unanimous approval—nor does, for that matter, such a foreign policy … The human mind in its day-by-day operations cannot bear to look the truth of politics straight in the face. It must disguise, distort, belittle, and embellish the truth—the more so, the more the individual is actively involved in the processes of politics, and particularly in those of international politics … Thus it is inevitable that a theory which tries to understand politics as it actually is and as it ought to be in view of its intrinsic nature, rather than as people would like to see it, must overcome a psychological resistance that most other branches of learning need not face.⁶⁶

In Morgenthau's view, the gap between what is normatively required of statesmen and what they actually do empirically was “further evidence of human irrationality.”⁶⁷

Are the classical realists right? Is rational thinking a precondition for Realpolitik? Is Realpolitik therefore a function of the psychology of state leaders? And is rationality, and therefore Realpolitik, as rare as Morgenthau suggests? Classical realist assumptions are based on sweeping generalizations with no real attention to substantiation. Cognitive psychologists, however, have reached strikingly similar conclusions. Rational thought is rare, as we rely primarily on cognitive systems that are unconscious, intuitive, and emotional.⁶⁸ Additionally, rationality is a trait that varies across individuals. Some are more objective and deliberative than others.

It has become commonplace in psychology to differentiate broadly between two decisionmaking “systems.”⁶⁹ In this “dual-processing” account of judgment, there is “System I” processing, which is automatic, intuitive, unconscious, reflexive, rapid, and impulsive. This is thought to be the system that guides most of our daily lives, only infrequently overridden by System II processing. The latter is deliberative, effortful, reflective, systematic, analytic, conscious, and explicit. System I is a “hot” system, often emotional in character, which induces individuals to act, quickly, without explicit thinking based on their “gut feelings.” System II is a “cold” system that proceeds slowly as individuals carefully consider their beliefs and choices. It is what one generally thinks of as procedurally rational in nature. Every individual utilizes both systems. Both are part of our neural architecture as human beings. System II processing is sometimes called in to check on and override our System I judgments. It is generally thought, however, that most tasks in our lives involve little such conscious and deliberate thinking.

Procedural rationality is marked by both greater objectivity and deliberation, the same attributes of rational thought stressed by classical realists. Not coincidentally, these elements are the opposites of, or at least opposed to, the two phenomena of which critics of rational choice make such frequent use—biases and heuristics.⁷⁰ The rational thinker tries to develop the most accurate understanding possible of the world around him or her. Keith Stanovich writes that “rationality concerns how well beliefs map onto the actual structure of the world.”⁷¹ Objectivity of this kind requires fighting the ever-present temptation to believe what one wants to believe, his or her “my-side” bias.⁷² Psychologists call this tendency “motivated bias,” motivated in the sense that we are willing our lack of objectivity; it is not a problem of cognitive limitations. The truth is often painful. Therefore, it is not surprising that psychologists have consistently uncovered ways in which individuals, even those in their field of expertise, choose to believe their own subjective truths despite evidence to the contrary.⁷³

Procedural rationality is also deliberative.⁷⁴ Instead of relying on intuitions, rational thinking requires analysis. As opposed to impulsively and reflexively made choices, rational thinking necessitates considered and therefore more time-consuming scrutiny. Rational thinkers are “reflective,” “engaged,” and “active.”⁷⁵ Rational thought, however, is relatively rare. For objective analysis, we substitute biased views. For deliberation, we substitute heuristics that simplify our decisionmaking tasks.

Rational thinking, it should be stressed, is not something judged by its success. That would be akin to ascribing irrationality to the gambler who bets on black when the roulette ball falls on red. Whether rational thinking yields better outcomes is an open empirical question. Rationality is something we assess based on its inputs, not its outputs—that is, by the cognitive style that guides our decisionmaking.

Psychological research also shows that individuals differ in the degree to which rational thought guides their decisionmaking. In other words, commitment to procedural rationality is a dispositional variable. Researchers find among individuals different levels of “epistemic motivation,” a commitment to think rationally, that is not reducible to other factors such as intelligence. Those with greater epistemic motivation deliberate harder and are more committed to developing an objective understanding of their environment. They continue to collect and process information after making judgments, remaining open-minded. Consequently, they do not fall prey as easily to the heuristics and biases that psychologists have used to undermine the rationality assumption in economics.⁷⁶ Rationality is a particular cognitive style. How we think is as important as what we think.

There is significant evidence that those who have greater epistemic motivation are more likely to behave in an instrumentally rational fashion. One cannot act in a calculating, strategic, instrumentally rational manner if he or she does not consciously consider the environment and deliberate in an objective way. Stanovich and colleagues have shown that those with higher epistemic motivation, captured largely with measures of cognitive closure and need for cognition, fall prey less frequently in laboratory experiments to the heuristics and biases so common to others.⁷⁷ In a recent laboratory experiment conducted with Joshua Kertzer and Mark Paradis, I find that the combination of egoism and commitment to rational thought leads participants in a bargaining game to better adjust to changes in the distribution of power.⁷⁸

Psychological research therefore offers reason to believe that rational thought, combined with an egoistic foreign policy orientation, is a precondition for Realpolitik, but also that Realpolitik will be rare because rationality is as well. Procedural rationality—most importantly, the commitment to objectivity and deliberation—will be associated with instrumental rationality presuming that statesmen are primarily interested in securing gains for their own countries, rather than for others (which is not always true, as the empirical case below shows). Rational thought is necessary for at least four instrumentally rational behaviors familiar to international relations theorists, although this list is not exhaustive. Below I describe each behavior, explain how it presupposes objectivity and deliberation, and note its historical association with realist thought.

utility maximization. If decisionmakers are optimizing given constraints, they must consider the pluses and minuses of different courses of action in securing their goals. Rationalist thinkers should exhibit what Philip Tetlock and his collaborators have called “cognitive” and “integrative” complexity, taking into account all of the relevant considerations and weighing them against one another.⁷⁹ Cognitive complexity measures the number of dimensions along which we consider a decision (sometimes also called “differentiation”); integrative complexity measures our ability to make compensating trade-offs across them when they conflict. Decisionmakers are also often forced to make choices between goals themselves. While a particular decision might sacrifice one aim, it might nevertheless be the right choice in terms of overall benefits. Jon Elster calls this “global maximization,”⁸⁰ which is equivalent to the realist stress on securing vital interests and compromising on matters of secondary importance.⁸¹

This type of behavior requires objectivity and deliberation. Statesmen must be honest with themselves, seeing things as they are, not as they wish them to be. One cannot have it all. Rather than a cognitively and integratively complex process, we often use simple evaluative rules—for instance, maximizing on one dimension rather than making trade-offs across several, or deontological thinking in which we consider only one factor regardless of the consequences.⁸² Decisionmakers might even deny that they are making any trade-offs, engaging in what Jervis calls “belief system overkill.”⁸³ In these cases, he or she judges that his or her choice is the most cost-efficient, the most likely, and the most ethical, the best along every dimension. Decisionmakers might have identical preferences. But if they have different cognitive styles, they might nevertheless make different choices.

situational judgments. Instrumentally rational statecraft guided by objective and deliberative thinking is situational. One does what is best given the circumstances, which are constantly changing.⁸⁴ A situational focus emerges naturally from rational thinking, which avoids simplifying heuristics that provide general guidelines, thereby reducing deliberation. Rationalists are “data driven” rather than “theory driven.”⁸⁵ Adapting to structural situations is another consistent theme in realist scholarship. The statesman, Morgenthau writes, “has a number of circumstances … to take into consideration. Circumstances are infinite, are infinitely combined; are variable and transient; he who does not take them into consideration is not erroneous, but stark mad … A statesman … is to be guided by circumstances; and judging contrary to the exigencies of the moment, he may ruin his country forever.”⁸⁶ Realists judge each problem on its merits and eschew the formulation of universal principles or solutions.⁸⁷

long-term thinking. Instrumental rationality is “characterized by the capacity to relate to the future,” as Elster writes.⁸⁸ This requires epistemic motivation, a commitment to procedural rationality. Only by evaluating the situation coolly and dispassionately, seeing it as it truly is, can one make the choice that is best for oneself in the long term. The very term “consequentialism” implies that we think forward to the consequences of our actions, rather than acting impulsively and automatically, envisioning the likely results of alternative paths of behavior. Long-term thinking is a consistent theme in realist scholarship.⁸⁹ In realism, writes Michael Smith, “What distinguishes the responsible from the merely well-intentioned statesman is the former's ability to foresee as far as possible the consequences of his actions.”⁹⁰

Playing the long game is not easy, however. Long-term thinking often requires restraint and short-term sacrifices for long-term gains.⁹¹ Monetary investments, for instance, require individuals to set aside the immediate pleasure of spending their earnings for the greater purpose of growing their nest egg to purchase more later. Stanovich distinguishes between “wants” and “wantons,” the latter being the impulsive and unthinking pursuit of that which gives us pleasure without reflection or consideration of future consequences.⁹² This again suggests that instrumentally rational behavior requires a particularly rational cognitive style.⁹³

strategic understanding. Instrumental rationality in situations of interdependence requires judging and anticipating the actions of others. Morgenthau formulates as a rule of good statecraft that “diplomacy must look at the political scene from the point of view of other nations.”⁹⁴ In addition to the complicated deliberations this requires, it necessitates an objective understanding of the others' motivations, which can be difficult if not impossible.⁹⁵ In interactions with adversaries, decisionmakers often proceed on the basis of the “inherent bad faith” model, in which they “know” that the other means them harm.⁹⁶ Rationality requires that foreign policy-makers think hard and honestly about how others view them, not how they want to be viewed. It necessitates that they recognize that others' behavior might be a product of a situation, not an inherent disposition, the latter being the cognitively easier and emotionally more comforting conclusion.⁹⁷ Understanding the perspective of others is the essence of the “security dilemma sensibility.”⁹⁸

How can scholars test my claim, inspired by classical realist insights and modern cognitive psychology, that rational thought is necessary for Realpolitik and that both are rare elements in foreign policy? A systematic inventory of all state leaders and their psychological attributes is prohibitively time-consuming and arguably impossible. Data sets of individual leader attributes are generally limited to easily identifiable characteristics such as age in office, profession, or military background.⁹⁹ Assessing psychology is much harder.

My solution is to focus on a historical example that should prove a hard case for my argument and an easy one for the ubiquity of realism. By the logic of structural realism, even the claims of those such as Waltz who do not believe that the system can predict foreign policy behavior, Realpolitik should be most prevalent and likely in situations in which countries face significant external threats and are particularly physically and militarily vulnerable.¹⁰⁰ Additionally, one can identify cases in which the normative and economic environments are more conducive to Realpolitik—most importantly, instances of state behavior before the modern liberal era marked by concern for human rights, strong state sovereignty norms, ethical prohibitions on the use of force, and economic interdependence. One should also select a non-American example, given that the United States is argued to have an exceptional foreign policy and political culture hostile to realism, perhaps as the result of having two oceans as borders.¹⁰¹

I choose the case of Prussia before and during the period of German unification. Prussia was the weakest of the five great powers, militarily exposed on multiple sides with no natural geographic features to protect it. Indeed, the German historian Otto Hintze long ago argued that Prussia's environmental constraints were reflected in its domestic institutions. Authoritarian government was necessary for Prussia to respond quickly to external threats.¹⁰² In the mid-nineteenth century, the second industrial revolution was in its infancy and had not yet made Prussia economically interdependent with its neighbors. The norms of the Concert of Europe that had softened the edges of power politics had deteriorated with the onset of the Crimean War in 1854.¹⁰³ Henri Dunant, the founder of the Red Cross, was only beginning to consider the idea of ethical limitations on military conduct.¹⁰⁴

The most important political figure in this period was Otto von Bismarck, who served as a loyal adviser to his Prussian king, Wilhelm I, for decades. As is well known, Bismarck was a political realist. I demonstrate how his realism owed to his rational thinking (a psychological variable) and distinguished him from his political peers and allies. The contrast with his domestic counterparts is particularly important, as it allows me to more precisely identify the effect of individual-level characteristics while controlling for other variables. Were I to compare Bismarck to an international contemporary such as Napoleon III or a German successor such as Gustav Stresemann, other features of the external situation would change, making it impossible to identify the precise effect of Bismarck's epistemic motivation or the uniqueness of Bismarck's Realpolitik. Even though leaders such as Wilhelm I faced the same severe international structural constraints (perhaps even greater ones given his ultimate responsibility), only Bismarck responded to them in a realist fashion.

The empirical portion of this article relies heavily on primary sources, captured in Bismarck's private letters and memoranda (complied after his death in the gesammelte Werke, or “collected works”) to reveal his cognitive style.¹⁰⁵ It is not meant so much to offer new historical interpretations of specific episodes, but rather to highlight the internal contestation over the direction of Prussian foreign policy and the implications for international relations theory, which I emphasize again in the conclusion.

Bismarck was one of the world's great realist statesmen. He embraced many of the substantive views associated with the realist theoretical tradition. Consistent with realist theory, he believed that power was the most decisive factor in international politics, writing: “Whichever finds itself in the combination that is weaker in the event of war is inclined to be more yielding; whichever completely isolates itself renounces influence, especially if it be the weakest among the Great Powers.”¹⁰⁶ He expressed at times a belief in classical realist tenets, such as the inherently self-interested quality of human nature.¹⁰⁷ Perhaps most famously, Bismarck prognosticated in his very first speech as Prussia's minister-president that German unification “will not be settled by speeches and majority decisions—that was the great mistake of 1848 and 1849—but by blood and iron.”¹⁰⁸

Yet, these traditional realist views do not do justice to the sophistication of Bismarck's Realpolitik, missing in particular the rational quality of his cognitive style—that is, his epistemic motivation. This section explores Bismarck's foreign policy egoism, his commitment to objectivity and deliberation, and shows how this combination led naturally to an instrumentally rational foreign policy approach that scholars call Realpolitik.

Bismarck was a Prussian, not a German, egoist.¹⁰⁹ He declared, “My country is Prussia, and I have never left my country and I shall never leave it.”¹¹⁰ Bismarck felt no identification with other countries: “I do not borrow the standard of my conduct towards foreign governments from stagnating antipathies, but only from the harm or good that I judge them capable of doing to Prussia.”¹¹¹ He wrote to a colleague in 1860, “In regards to domestic Prussian policy I am, not merely out of custom, but rather out of conviction and utilitarian grounds so conservative,” and will be loyal “even for a king, whose policies do not appeal to me; but only for my king. In regards to the circumstances of all other lands, I recognize no kind of principled commitment for the policy of a Prussian. I regard policy solely by the measure of its usefulness for Prussian goals. In my view, the duty of a Prussian monarchy is limited to the borders of the Prussian empire drawn by God.”¹¹²

It would be sloppy, however, to call Bismarck a Prussian “nationalist,” because his loyalty was to the Prussian state and its monarchy, which for him were one and the same. Bismarck asked rhetorically, “For why, if not by divine decree—why should I bow down to these Hohenzollerns?¹¹³ They are a Swabian family no better than my own and absolutely no concern of mine.”¹¹⁴ A nationalist at the time was one who identified with the self-determination claims of the German people—in other words, a liberal proponent of democracy. Bismarck instead had strong conservative political principles; he was a genuine believer in a God-given hierarchical order of divine right, monarchical rule, and aristocratic privilege. These principles were under threat in his time, a threat brought home by the democratic revolutions that swept Europe and, in 1848, led to the grudging promulgation of a constitution in Prussia.¹¹⁵

Almost all observers of Bismarck comment on his epistemic motivation.¹¹⁶ Bismarck was committed to seeing things as they were—objectively and realist-ically. Bismarck frequently compared himself to a “natural scientist.”¹¹⁷ He wrote a colleague, “I take great care in all my official tasks to see them with the greatest possible objectivity and correctness.”¹¹⁸ Bismarck was highly deliberative: “After his scientific manner,” he took “action only after extensive analyses and experiments” and would “proceed carefully.”¹¹⁹ Bismarck selfconsciously strove to avoid allowing passion and emotion to overcome his judgment.¹²⁰ He proclaimed, “Not even the king himself has the right to subordinate the interests of the fatherland to personal feelings of love or hatred toward foreigners.”¹²¹

Bismarck's foreign affairs egoism and epistemic motivation led him to adopt naturally to a utilitarian, consequentialist, instrumentally rational approach to politics. Prussia must do its best in light of the structural circumstances it faced. As Bismarck stated, “One has to reckon with a series of probabilities and improbabilities and base one's plans upon this reckoning.”¹²² Albrecht von Roon, who served as Prussia's minister of war during the 1860s and worked with Bismarck closely, observed his decisionmaking process: “To construct the parallelogram of forces correctly and from the diagonal, that is to say, that which has already happened, then assess the nature and weight of the effective forces, which one cannot know precisely, that is the work of the historic genius who confirms that by combining it all.”¹²³ Clemens Theodor Perthes, a prominent professor of law of the period, wrote how Bismarck “calculates so coldly” and “prepares so cunningly.”¹²⁴ One notes here that, in the views of his peers, Bismarck's rationality set him apart. His Realpolitik was rare. Historians agree.¹²⁵

As politics (and life in general) was full of obstacles and constraints, Bismarck stressed the necessity of navigating them as best possible. This is the definition of instrumental rationality. Politicians must be content with what was possible and not overplay their hand in the pursuit of the ideal. Bismarck's favorite Latin proverb was “unda fert nec regiture” (“One cannot make a wave, only ride it”).¹²⁶ In other words, Bismarck's realism was realistic. Bismarck said after his retirement, “Positive undertakings in politics are extraordinarily difficult, and when they succeed, one should thank God that they led to a boon and not find fault with trivialities … but rather accept the situation.”¹²⁷ As I show below, Bismarck's pragmatism often made him an advocate of restraint. He would advise others, “When we have arrived at a safe harbor we should be satisfied and care for and maintain what we have won.” This was a general rule of politics for him “in confessional as well as in social relations … We want to carefully hold on to what we have, also with the concern that we will lose it if we do not value it.”¹²⁸

In Bismarck, one sees all of the four manifestations of instrumentally rational foreign policy mentioned above: utility maximization, situational judgments, long-term thinking, and strategic understanding. Bismarck consistently emphasized the importance of adapting to each situation.¹²⁹ Circumstances were constantly changing. The statesman “has to expect random disturbances like the farmer does with weather conditions. Even after the greatest success one cannot say with certainty: ‘Now I have succeeded, I am finished’ and look back at what was achieved with satisfaction.”¹³⁰ Therefore, there was no one-size-fits-all answer. Circumstances mattered: “To demand first and foremost ‘consistency’ of a statesman means giving him the freedom to decide based on the changing requirements of states, the changed situation abroad … He must always be directed by the prevailing circumstances at the time; he cannot command the facts before him and the currents of the time, but rather cleverly use them for his purposes. He must observe or seek out every favorable opportunity to implement what seems to him correct and appropriate for the fatherland's interests … A governing program that applies to all times cannot exist because the times change.”¹³¹

Bismarck distinguished his situational approach against one in which there were inviolable principles of conduct: “One can only recognize a principle as generally applicable if it applies to all circumstances and all times.”¹³² Later in his career, he complained, “Already many have spoken of my political principles. The professors and their imitators in the newspapers constantly decry the fact that I have not revealed a set of principles by which I directed my policies. Because they have as yet scarcely outgrown the political nursery, the Germans cannot accustom themselves to regard political affairs as a study of the possible.”¹³³

The goals and strategies of opponents were key elements of the situation with which leaders had to contend. As an egoist pursuing only Prussia's interest, Bismarck saw his country as engaged in strategic interaction with others. “In politics,” he argued, “no one does anything for another, unless he also finds it in his own interest to do so.”¹³⁴ At another point, he stressed: “My belief is that no one does anything for us, unless he can at the same time serve his own interests.”¹³⁵ It was instrumentally important to understand opponents' motivations, to see things as they saw them. “Correct evaluation of the opponent is … indispensable to success,” he observed.¹³⁶

Bismarck's structural understanding of politics and foreign policy led him to stress the importance of seizing opportunities when the circumstances were favorable, given that these could not easily be re-created. He stated, “History with its great events … does not roll on like a railway train at an even speed. No, it advances by fits and starts, but with irresistible force when it does. One must just be permanently on the look-out and, when one sees God striding through history, leap in and catch hold of his coat-tail and be dragged along as far as may be.”¹³⁷

Seizing opportunities required farsightedness and the acceptance of short-term costs for long-term gains.¹³⁸ Bismarck wrote, “The statesman must see things coming ahead of time and be prepared for them … An indispensable prerequisite is patience. He must be able to wait until the right moment has come and must precipitate nothing, no matter how great the temptation.”¹³⁹ Patience was not easy. The statesman “must be able to wait until the correct moment has arrived and not rush, even when the incentive is so great. If man takes the most beautiful pastry out of the fire too early, it collapses.”¹⁴⁰

In the previous section, I argued that Bismarck's psychology was a precondition for his Realpolitik. This instrumentally rational type of foreign policy is predicated on both egoism and epistemic motivation. Below I show that this combination and its foreign policy consequences differentiated Bismarck from others in his country, even from those with whom he shared similar political interests. His conservative peers and allies objected to his narrowly Prussian focus. In addition, they exhibited a different, less rational cognitive style that led them to different conclusions even when they all shared common goals.

It was as a strident conservative opponent of the liberal opposition in the late 1840s that Bismarck made a name for himself in Prussian politics. Bismarck's interventions attracted the attention of his political patrons—most notably, the Gerlach brothers, Leopold and Ludwig, who formed the “Christian-Germanic circle” to promote their conservative political ideas. The Gerlachs also brought Bismarck into the “camarilla,” a shadow group of advisers to the king seeking to rid Prussia of liberal ideas after 1848. Bismarck was also active within the Kreuzzeitung Party, named after the newspaper that served as a mouthpiece for reactionary and conservative ideas. Owing to these activities, in 1852 Bismarck became the Prussian envoy to the German Bund, a somewhat shocking appointment for a political novice, as it put him at the center of German affairs and interaction with Prussia's rival—Austria.¹⁴¹ The Bund was a federation of dozens of German states erected in the wake of the Napoleonic Wars, dominated by Austria and Prussia.

Bismarck owed his early political opportunities to the domestic views he shared with conservatives, but foreign policy would drive a wedge between him and his conservative friends. Stationed in Frankfurt, Bismarck developed his belief that Austria was Prussia's primary competitor and its primary obstacle in reaching Prussia's potential as a great power. In his memoirs, he complained that at the time, “Prussia was nominally a Great Power, at any rate the fifth.”¹⁴² Of Austria he wrote, “My period of office here, nearly seven years of it, has … been one continuous struggle against encroachments of all kinds, against the incessant attempts that have been made to exploit the Confederation as an instrument for the exaltation of Austria and the diminution of Prussia.”¹⁴³ Austria was Prussia's main adversary because it interfered the most in Prussia's immediate sphere of interest, that of the German states. War was not necessarily foreordained, but for Bismarck, the only other possibility was an agreement on zones of influence. There could be a “political or geographical line of demarcation,” most likely the Main River.¹⁴⁴

The other obstacle to Prussia's aims of greater influence in Germany, particularly Bismarck's desire for Prussia to be the cornerstone of a unified German state excluding Austria, were the smaller German states. The medium-sized monarchies of Baden, Bavaria, Saxony, and Württemberg, in particular, feared that any consolidation would cost them their influence and perhaps even their crowns. These forces of what Bismarck called “particularlism” had long stymied efforts to unify the German states. Bismarck wrote that the “key to German politics was to be found in princes and dynasties, not in publicists, whether in parliament and the press or on the barricades … With the promotion of German unity there was a prospect of the diminution of their independence in favour of the central authority or the popular representative body.”¹⁴⁵ As sovereign states in the Bund, the medium-sized German states could play Austria and Prussia against each other. The smaller German states were, in Bismarck's words, “using our federal relationship as a pedestal to play the European power.”¹⁴⁶ With the Habsburgs, they could always outvote Prussia in the Bund.

Bismarck's views on Austria and Germany caused severe frictions and ultimately destroyed his relationships with his conservative patrons. Austria, as well as Russia, were fellow members of the Holy Alliance, dedicated to the preservation of monarchical rule and the repression of democracy and liberalism since 1815. It was a “league against revolution.”¹⁴⁷ The governments of all three powers were unified in their belief in the legitimacy of absolutist rule and their contempt for government by the masses—even dictatorships such as Napoleon III's, given that his right to rule was conferred by the “general will” of the French people rather than aristocratic lineage. Bismarck's political allies were “romantic conservatives” who felt a kinship with Austria.¹⁴⁸ They believed in conservative solidarity, a prosocial, interstate bond across the countries that also extended to the German princes and kings. The fear of liberal revolution and the forces of nationalism persisted well past 1848, given liberal and nationalist movements in France and Italy, among others.

Bismarck's realism put him at odds with the camarilla and the Kreuzzeitung because of both its egoism and its deliberative quality, something Bismarck frequently acknowledged and lamented.¹⁴⁹ Bismarck was egoistically focused on Prussian interests. He explicitly denigrated romanticism as a guide for foreign policy, a term into which he “lumped everything that did not directly serve to uphold and extend the power of the [Prussian] state.”¹⁵⁰ In one of his most famous speeches, he proclaimed, “The only sound basis for a large state is egoism and not romanticism; this is what distinguishes a large state from a small one.”¹⁵¹

Whereas the romantic conservatives were reluctant to interfere with what they regarded as the legitimate rule of fellow monarchical powers, feeling a bond with them that extended past Prussia's borders, Bismarck had no such compunction. He wrote a close friend in 1861, before his appointment as minister-president: “The system of solidarity of the conservative interests of all countries is a dangerous fiction … We arrive at a point where we make the whole unhistorical, godless and lawless sovereignty swindle of the German princes into the darling of the Prussian Conservative Party … Our government is in fact liberal domestically and legitimist in foreign policy. We protect foreign monarchical rights with greater tenacity than our own … to the point of utter blindness to all the dangers to which Prussia's and Germany's independence is exposed as long as the madness of the present federal constitution [the Bund] survives.”¹⁵² A letter to Prussian War Minister von Roon contained the same themes: “No one will thank us for our love in the princely houses from Naples to Hanover, and we practice toward them real evangelical peaceful love at the cost of the security of our own throne. I am loyal to my king to the end, but toward others I feel … not a trace of commitment to lift a finger for them.” He expected no good results for Prussian foreign policy until it was made more “independent from dynastic sympathies.”¹⁵³

Bismarck's issues with his colleagues were not only substantive, reducible to varying degrees of foreign policy egoism. They were also cognitive, owing to a different and more rational way of thinking. The romantic conservatives viewed their alliance against democracy and liberalism as a matter of principle that could not be compromised, regardless of the consequences. The Gerlachs and other romantic conservatives made decisions in a deontological fashion, whereas Bismarck was a utilitarian.

This difference in cognitive style is first evident in Bismarck's personal dispute with Leopold von Gerlach over the Bund envoy's suggestion to invite Napoleon for a state visit to Berlin. Bismarck sought better relations with Napoleon because Prussia's traditional alliance with Austria and hostility to revolutionary France reduced its leverage in pursuing its interests vis-à-vis the Habsburgs, as well as the smaller German states. “As long as each of us is convinced that a portion of the European chess-board will remain closed against us by our own choice, or that we must tie up one arm on principle while everyone else employs both of his to our disadvantage, this sentimentality of ours will be turned to account without fear and without thanks,” Bismarck wrote Gerlach.¹⁵⁴ He did not want an alliance with France, only to create the appearance that one was possible.

Napoleon, however, was an illegitimate ruler and persona non grata to Prussian conservatives, so even such a parlay was wholly unacceptable.¹⁵⁵ Gerlach wrote that “it depresses me that … you have allowed yourself to be diverted from the simple choice between Right and Revolution. You play with the idea of an alliance with France and Piedmont, a possibility, a thought, that for me lies far away as it should be, dear Bismarck, for you.”¹⁵⁶ No pragmatic compromises could be made. “If a principle like that of opposition to the Revolution is correct,” Gerlach continued, “then we must also constantly stick to it in practice.”¹⁵⁷ He had before cautioned Bismarck, on an entirely different matter, “of the apostle's warning against doing evil that good may come.”¹⁵⁸

Even though Bismarck and Gerlach shared a set of ethical concerns—namely, a commitment to conservative, anti-revolutionary principles—they preferred different policies as a result of their different degrees of rational thinking. For Bismarck, using France as a tool was distasteful for ideological reasons, but something Prussia must nevertheless be willing to do given the larger overall goals: “I am convinced that it would be a great misfortune for Prussia if her government should enter into an alliance with France, but, even if we make no use of it, we ought never to remove from the consideration of our allies the possibility that under certain conditions we might choose this evil as the lesser of the two,” he wrote.¹⁵⁹ This was yet another instance of the pragmatic “art of the possible.” Bismarck had “no desire to make an apology for persons and conditions in France; I have no predilection for the former and regard the latter as a misfortune for that country; I only desire to explain … that it is neither sinful nor dishonourable to enter into closer connexion, should the course of politics render it necessary … That this connexion is in itself desirable I do not say, but only that all other chances are worse, and that we must, in order to improve them, go through with the reality or the appearance of closer relations with France.”¹⁶⁰ Bismarck remarked, “As a romanticist, I may shed a tear over” the deposed French monarch's fate, “but as I am, France counts for me, without regard to the person at its head for the time being, merely as a piece, though an unavoidable one, in the game of political chess—a game in which I am called upon to serve only my own king and my own country.”¹⁶¹ Gerlach also seemed to acknowledge the cognitive nature of their disagreement when he penned, “I want to acknowledge willingly the practical side of your view.”¹⁶²

Although for the moment, Bismarck continued to count the conservatives as his political allies, his realism left him without a political home. His anti-revolutionary ideals angered liberals; his foreign policy views were anathema to conservatives. It is striking that the great foreign policy realist had no real consistent political allies. Bismarck's Realpolitik was rare, despite the severe international constraints under which his country was operating. All historians seem to agree on this point. Lothar Gall writes that “the anti-idealist sobriety and the often cynical skepticism that Bismarck exhibited in his politics very early on and continued to profess more and more outspokenly constituted an extraordinary challenge to his time. They cut him off from the various political groups and their respective ideals and convictions … It turned him, in other words, even in the years of his greatest success, into a lone wolf.”¹⁶³ Jonathan Steinberg writes, “No crowds followed him and no party acknowledged him as leader.”¹⁶⁴ Bismarck cared little, writing, “I am also as indifferent to ‘revolutionary’ or ‘Conservative’ as I am to all phrases.”¹⁶⁵ Feuchtwanger argues that Bismarck was “not a typical reactionary Junker, that aristocratic class of which he was a member, but he was not a liberal either.”¹⁶⁶ “Neither liberals nor conservatives could regard him as one of theirs,” observes Edgar Feuchtwanger.¹⁶⁷ His unique way of thinking made him a “man between the fronts in ‘no man's land,'” writes Gall. “Hardly anyone had occasion to identify with him personally or see him as symbolizing a specific political direction and a set of convictions.”¹⁶⁸ “Among all these Hohenzollern there is not one who supported him,” writes Emil Ludwig. “There is no real confidence between Bismarck and any of the ministers, generals, courtiers, or leaders of parties. Fundamentally he has no party.”¹⁶⁹ Realpolitik, rather than being the natural approach of any statesman in the high circles of Prussian foreign policy, actually separated Bismarck from almost everyone else.

At every point during the 1850s, Bismarck seemed to be alone in his views. During the Crimean and Franco-Austrian wars, he advocated taking advantage of Austrian preoccupations. In 1854, he wrote, “Great crises make the weather favourable to Prussia's expansion, if we exploit them fearlessly and perhaps ruthlessly; if we want to go on growing, then we must not be afraid to stand alone with 400,000 soldiers, especially as long as the others are fighting.”¹⁷⁰ King Friedrich Wilhelm IV, however, could not countenance such a move against a fellow monarchical power, contrasting his approach with that of the perceived illegitimate ruler Bonaparte. He told Bismarck, “A man of Napoleon's sort can commit such acts of violence, but not I.”¹⁷¹ Instead, Prussia signed a defensive alliance with Austria. Bismarck remembered, “I could not … avoid a feeling of shame, of bitterness, when I saw how, in the face of the demands of Austria, not even presented in courteous form, we sacrificed all our own policy and every independent view.”¹⁷² Similarly, when Austria was held down in Italy in 1859 in a war with France, he advised, “The current situation yet again holds the jackpot for us if we just let Austria's war with France really bite and then move south with all our armies, carrying the border posts with us in our knapsacks and banging them in again either at the Lake of Constance or wherever the Protestant confession ceases to predominate.”¹⁷³ His ideas were ignored.

As explained above, if Realpolitik is the norm rather than the exception in foreign policy, then one should rarely see an isolated and lonely realist in practice. Bismarck, however, was not the norm, even in a geopolitical context that should have structurally favored his approach. Prussia was surrounded by hostile powers and a consistent rival of Austria in German affairs, something that Bismarck constantly pointed out, to no avail. Importantly, Bismarck's complaints were made to those in similar structural positions, responsible for the safeguarding of Prussian interests and security and therefore susceptible to the same systemic pressures.

Bismarck's Realpolitik continued to distinguish and isolate him when he became the minister-president of Prussia in 1862, the most important political position in the country other than the crown. It was a surprising appointment, one that King Wilhelm I made only because of his intense and intractable conflict with the Prussian parliament (the Landtag). Bismarck was brought in as a Konfliktminister because of his reputation as a heavy-hitting arch-conservative in domestic affairs. Bismarck's ability to deal forcefully with the Landtag was deemed more important than his unorthodox foreign policy views, which were a disadvantage.¹⁷⁴ In terms of the latter, he was regarded as a Bonapartist, to which he responded: “If I am to be falsely described as a devil, at least let it be as a Teutonic and not as a Gallic one!”¹⁷⁵ These views had earlier cost him the post of foreign minister.¹⁷⁶ Under Bismarck, the crown muzzled the press, in addition to other anti-democratic measures.¹⁷⁷

Bismarck continued to resist the legitimist sympathies of colleagues who did not share his narrow foreign policy egoism, sinking an effort by the Habsburgs to unify Germany on Austrian terms. In the summer of 1863, Emperor Franz Josef II proposed a reform of the Bund as a preparatory stage to a voluntary union that would privilege Austria. The Bund would have a new executive organ, a federal directorate in which the Prussians might be outvoted, as well as a chamber of deputies whose members were to be chosen by parliaments of member states (rather than direct elections).¹⁷⁸

The Austrians invited the German monarchs to a “Congress of Princes” to discuss the issue. All the sovereigns quickly accepted the offer, and Wilhelm I felt an obligation to go as well. The Saxon king had visited him personally to urge him to attend. “Thirty reigning princes, and a King to take their messages!” he famously said.¹⁷⁹ This was another case of the attachment felt by the king to other sovereigns, which for Bismarck distracted from Prussia's egoistic interests. Wilhelm “favoured the Austrian proposal because it contained an element of royal solidarity in the struggle against parliamentary Liberalism,” Bismarck believed.¹⁸⁰

The minister-president's effort to convince the king not to participate led to a severe fight. To prevail, Bismarck had to threaten to resign, a threat to which he frequently resorted.¹⁸¹ This decision was tremendously important for the subsequent direction of German unification, however. Bismarck later argued, “Had I dropped my resistance to the King's efforts to go to Frankfort, and, according to his wish, accompanied him thither in order, during the congress, to convert the rivalry of Austria and Prussia into a common warfare against revolution and constitutionalism, [it] would have closed the road to German nationality.”¹⁸² Historians agree. Steinberg calls it the “most important achievement of Bismarck's entire career.¹⁸³

Bismarck faced similar resistance to any attempt at Prussian expansion that threatened legitimist solidarity during the Schleswig-Holstein conflict. The crisis erupted in March 1863, when the Danish king, Frederick VII, in violation of the London Protocols of 1854, attempted to impose a new constitution on the two duchies, which had majority German populations. The Danish action elicited nationalist outrage, especially in the smaller German states, on behalf of the embattled and oppressed Germans, who they believed deserved the right of self-determination.

Bismarck instead wanted to use the opportunity to annex the two provinces. “For me annexation by Prussia is not the highest and most necessary aim but it would be the most agreeable result,” he wrote at the time.¹⁸⁴ His conservative colleagues, however, were again opposed to his policies on non-egoistic grounds. In a crown council meeting in February 1864, everyone else remained silent except the crown prince, who “raised his hands to heaven as if he doubted my sanity.”¹⁸⁵ The king's romantic commitment to the principle of legitimacy and conservative solidarity led him to reject his minister-president's plan. He repeatedly rebuffed Bismarck with the answer that he had no rightful claim to the duchies.¹⁸⁶ Bismarck's suggestions were so controversial that the king had them stricken from the minutes of the meeting; Wilhelm believed that Bismarck would not want this recorded. The minister-president was not embarrassed. He had them reinserted.¹⁸⁷

Despite this opposition, with skillful manipulation by Bismarck, the conflict ended with the Habsburgs and Hohenzollerns gaining joint administration over the territories in a process colorfully captured by Stacie Goddard.¹⁸⁸ In a meeting at Bad Gastein, the two monarchs divided power, with Austria getting Holstein, Prussia controlling Schleswig, and a smaller area called Lauenberg to be sold to Prussia. What is most interesting for the purposes here, however, is the domestic opposition to Bismarck's plans, which indicates again how rare his Realpolitik made him in Prussian affairs.

Frictions with the Austrians over the disposition of Schleswig and Holstein provided Bismarck with the spark he needed to incite a final showdown with Austria in the hopes of expelling the Habsburgs from German affairs forever. This was an uphill struggle, however, as his colleagues opposed his Realpolitik approach. Bismarck continued to press the king and others in the crown council for annexation of both provinces, with little initial success. A military officer recounted a meeting in February 1866: “Bismarck gave hints that the war must decisively achieve the rounding off of Prussian territory … The King answered angrily, that there is no question of war yet and still less of deposing German princes.”¹⁸⁹ The minister-president described himself at the time as “exasperatingly using spurs, so that the old, noble racer” would act. He had to overcome the “conservative disposition of the king.”¹⁹⁰

Matters reached a crisis point in June 1866, when the Austrians violated the terms of the Gastein Convention by allowing the Holstein parliament to meet. Wilhelm responded wrathfully, “Austria follows up perfidy with falsehood, and falsehood with a breach of faith.”¹⁹¹ He was ready to fight for Prussian honor, the emotional spark that Bismarck needed to convince the king of his course. Bismarck finally had the war he wanted, but he had had to drag his colleagues into it largely against their will, mainly because they lacked Bismarck's foreign policy egoism.

The previous sections laid out the persistent differences between Bismarck and other conservative Prussians on foreign policy in which the minister-president consistently advocated a more aggressive approach vis-à-vis Austria. Do the foreign policy divisions between Bismarck and his colleagues not simply amount to differing conceptions of Prussian interests? Could one not simply say that Bismarck had more expansionist aims and leave it at that? If that is the case, then psychology and rational thinking have little to say about this period in history. The dynamics of the Austro-Prussian War of 1866 show that this is not the case. In the wake of Prussian victories, Bismarck had to constrain colleagues who wanted to push Prussian gains further than he thought advisable. The difference can be attributed to how Bismarck's thinking differed from that of others—in particular, his king.

The interesting element of the Austro-Prussian War of 1866 is less about how it began and how it was fought, and more about how it ended. It was not much of a contest. The “Fraternal War” (Brüderkrieg) was also known as the “Seven Weeks' War.” The Prussians decisively defeated the Austrians at the Battle of Königgratz, ending any chance of Austrian victory. The question was how far the Prussians would push their mastery of the Habsburgs. The episode shows all the manifestations of an instrumentally rational foreign policy: the careful ranking of preferences and trade-offs in light of constraints, an understanding of the strategic situation, a consideration for long-term consequences, and a situational approach to foreign policy based on the needs of the moment.

Bismarck's Realpolitik guided him not to exploit the Prussian success, as a crude understanding of realism might expect, but rather to engage in strategic restraint. This restraint looked like “retreat in the very moment of victory,” writes Daniel Ziblatt.¹⁹² As noted, however, Realpolitik is marked by a global understanding of one's position. It involves a consideration of not just the short term but also the long term, not just the particular adversary one is facing at the time but also how one's actions are viewed in the broader environment.

Both of these considerations led Bismarck to conclude that the Prussians should seek a negotiated peace that left the Austrian Empire intact, with no loss in territory. He advised, “His Majesty to make peace on the basis of the territorial integrity of Austria.”¹⁹³ Ludwig writes, “As a liegeman of the king of Prussia … his [Bismarck's] only concern was with the expansion of Prussia; and he would much rather, after the manner of earlier centuries, have conquered German princes in order to enlarge Prussia, than have troubled himself about the problems of the German Federation … But his sinister intelligence … and his clear view of reality, overpowered these wishes … He kept his eyes fixed on what was attainable, ignored what was merely desirable.”¹⁹⁴ One expects more rational thinkers to be able to distinguish between what is preferred and what is feasible. They engage in utility maximization and trade-offs across multiple goals.

Bismarck wanted to limit Prussian war aims to the expulsion of Austria from northern German affairs and the creation of a new, but small, unified German state in northern Germany, which could be added to gradually, not all at once. This had been Bismarck's position even before the war began. He wrote Helmuth von Moltke, the head of the Prussian army, in March 1866: “The goal … is the agreement of Austria to the new German constitution we are striving for. Limiting our ambitions to northern Germany also offers the … possibility of an understanding with Bavaria.” He cautioned against the “occupation of Elbe duchies,” because this would led to a “new range of continuous conflicts and unabated burdens.”¹⁹⁵ He would later recount that “a quick peace was very surprising for some,” but that he pragmatically “thought it the best that could be done.”¹⁹⁶ It was a “mistake to place the entire result in question in order to win a few more square miles of territorial concessions or a few million more reparations from Austria,” he advised the king.¹⁹⁷ At another point, he wrote a colleague, “As far as I am concerned the difference between a successful reform of the German federation and the direct acquisition of some countries is not practically high enough to risk the future of the monarchy. Our political requirements are limited to the disposition of the powers of northern Germany in some form.”¹⁹⁸ Prussia should not go south of the Main River, a limit to which France indicated its acquiescence and support.¹⁹⁹

Bismarck demonstrated a combination of strategic understanding and long-term thinking in his views about Austria. He recounted, “It was my object, in view of our subsequent relations with Austria, as far as possible to avoid cause for mortifying reminiscences, as it could be managed without prejudice to our German policy. A triumphant entry of the Prussian army into the hostile capital would naturally have been a gratifying recollection for our soldiers, but it was not necessary to our policy. It would have left behind it, as also any surrender of ancient possessions to us must have done, a wound to the pride of Austria, without being a pressing necessity for us, would have unnecessarily increased the difficulty of our future mutual relations.”²⁰⁰ He continued, “If Austria were severely injured, she would become the ally of France and of every other opponent of ours; she would even sacrifice her anti-Russian interests for the sake of revenge on Prussia.”²⁰¹ The same was true of the lesser German states.²⁰² This observation was mentioned by Bismarck in his private conversations as well:²⁰³ Austria “must be made into a friend, and as a friend it could not be completely powerless.”²⁰⁴

Bismarck was also concerned about the broader European environment, demonstrating the security dilemma sensibility of the rationally thinking realist and the ability to maximize benefits across multiple dimensions (i.e., cognitive complexity). Disturbing the equilibrium any further would create fear in London, Paris, and Moscow and invite outside intervention, particularly if Prussia pushed the fight into Hungary and left itself exposed.²⁰⁵ Bismarck was particularly worried about Napoleon and therefore pushed for a quick peace. After the Königgratz victory, he believed “we could not lose a fortnight without bringing at least the danger of French interference very much nearer than it otherwise would be.”²⁰⁶ He wrote to King Wilhelm that Napoleon had consented to adding 4 million northern German inhabitants, “but one could not count on support of anything more far-reaching or calculate even how these Prussian demands would be received by the other great powers.”²⁰⁷ He complained to his wife that he had the responsibility of “reminding people that we do not live alone in Europe but with three other powers, who hate and envy us.”²⁰⁸ His preoccupation with the appearance of Prussian motives was also evident before the war. Bismarck argued, “We cannot allow to be seen, in conflict with Europe, as committed in advance to a wanton war of aggression.”²⁰⁹ The Austrians had to be seen in Europe to be hindering natural German national aspirations.²¹⁰ Bismarck, of course, ultimately had aims on the southern German states. In a meeting with the crown prince, he described his limited aims in northern Germany as a “step toward greater unification.”²¹¹ Only a patient, long-term, stepwise process would allow for success, however.²¹²

The king and the military, however, had different plans. They wanted to continue the fight, seizing Vienna and even potentially going on to Hungary, as well as demand significant territorial concessions. In addition to Austria's expulsion from any new federation, Wilhelm proposed a striking list of his desired territorial annexations from Austria and its allies—Ansbach-Bayreuth, Austrian Silesia, Bohemia, East Friesland, Hanover, and part of Saxony, in addition to Schleswig-Holstein.²¹³ These would have meant an expansion of Prussia past the Main River. The Prussian ambassadors in Paris and Munich complained that Bismarck did not want to complete the unification of Germany.²¹⁴

These divisions show that the divide separating Bismarck and his political allies was not simply one of reluctant romantics and a revisionist realist, but rather reduced to fundamentally different styles of thinking. Bismarck could be both expansionist and forgiving, depending on what he believed the strategic situation dictated based on a cold, objective analysis. The king, on the other hand, had by all accounts been emotionally aroused by the conflict, leading him to violate a central tenet of even the most basic rationalist assumptions—consistent preferences. Bismarck had had to push Wilhelm I into the conflict. Now he had to restrain him. “My greatest difficulty was first to get the king into Bohemia and then to get him out again,” was Bismarck's pithy memory of the divide. “The trial of wills Bismarck had over this with his master were among the most serious of their long relationship,” writes Feuchtganger.²¹⁵

In their fights about how and when to end the war, Bismarck was all sober and deliberative thinking, the king all deontological indignation and impulse. The minister-president wrote to his wife, “If we do not exaggerate our claims and do not believe that we have conquered the world, we can arrive at a peace worth the effort. But we are as quickly intoxicated as discouraged, and I have the thankless task of pouring water into the effervescent wine.”²¹⁶ Wilhelm's thinking was more oriented toward the short term and was less instrumental and utilitarian. According to Bismarck, the king, in a stormy session, “said that the chief culprit could not be allowed to escape unpunished, and that justice once satisfied, we could let the misguided partners off more easily, and he insisted on the cessions of territory from Austria.”²¹⁷ Bismarck's position was the same in regards to the smaller German powers.²¹⁸ A senior military officer wrote, “The peace negotiations are going well and the peace would have been signed if the King had not made difficulties. He insists that Austria surrender territory to us … It looks as if this point of honour is the stumbling block.”²¹⁹ Bismarck summarized that the “king and the military party … were very proud of the great victory of Prussian weapons and believed that such a great success demanded a greater reward.”²²⁰

This was not a case of a leader adjusting his aims in light of military successes, as a rationalist model would suggest.²²¹ As seen before, Wilhelm's initial resistance to fighting Austria had never been based on power considerations; it was principled in character. The king would not countenance a break in conservative solidarity. Now, however, after the conflict had started, he wanted retribution. A.J.P. Taylor writes that this was not a matter of consequentialist judgment for Wilhelm. There is no evidence that the king and others who wanted to push Prussian gains were trying to demonstrate credibility or were driven by some other instrumentalist motivation: “The king … had been dragged reluctantly into war … Now he regarded them [the Austrians] as wicked and insisted that they be punished. For him, as for many lesser mortals, war was a matter of moral judgment, not an instrument of power.”²²²

This reaction makes sense given Wilhelm's lower level of rational thought. The king was highly emotional during this period. He was not thinking clearly, Bismarck believed, intoxicated by military success. “The strong need he [the king] felt of pursuing the hitherto dazzling course of victory perhaps influenced him more than political and diplomatic considerations.”²²³ This view is shared by historians as well.²²⁴ There was a long-standing stylistic difference between the king and Bismarck. Ludwig observes, “The king had, as a rule, the equable pulses of an heir; but he would become excited at critical moments, and give way to furious passion.” His impulsiveness was the opposite of the measured approach of Bismarck, who “in moments of crisis … was ice-cold and clear-sighted.”²²⁵ Bismarck treated Wilhelm as a father “whose fits of temper and caprices must be accepted.”²²⁶

Bismarck described his efforts to convince the king to listen to reason. He explained that Prussia must be dispassionate at this moment. He “regarded the principle of retaliation as no sound basis for our policy, since even where our feelings had been injured, it ought to be guided, not by our own irritation, but by consideration of its object.”²²⁷ He also demonstrated objectivity: “Austria's conflict in rivalry with us was no more culpable than ours with her.”²²⁸ Bismarck's objectivity allowed him to avoid the temptation of “my-side bias” in which Prussian interests were held to be more ethically justified than those of Austria, a demonstration of epistemic motivation. His position was based explicitly on instrumental rationality, one that weighed costs and benefits and focused on securing vital interests first. Bismarck told the king, “We were not there to sit in judgment, but to pursue the German policy … Our task was the establishment or initiation of a German national unity under the leadership of the King of Prussia.”²²⁹ He told the sovereign that punishment was counterproductive and shortsighted: “I tried to make clear to him that one could hardly fatally wound those with whom later one would want and indeed have to live.”²³⁰

Following Bismarck's threats of resignation, the king relented after his son, the crown prince, intervened. Wilhelm sent a note to the minister-president whose exact wording is not known. Bismarck paraphrased it as reading, “Inasmuch as my Minister-President has left me in the lurch in the face of the enemy, and here I am not in a position to supply his place … I find myself reluctantly compelled, after such brilliant victories on the part of the army, to bite this sour apple and accept so disgraceful a peace.”²³¹ Bismarck had convinced the king to be a realist. Apples cannot always be sweet. This was the lesser evil in fruit form.

In the end, Prussia confined its annexation to the area north of the Main River, in northern Germany, the most important territories being Hanover, Saxony, and Schleswig-Holstein. The three large southern states—Baden, Bavaria, and Württemberg—retained their independence but were made to sign treaties of alliance. Upon hearing the generous terms, the Bavarian minister with whom Bismarck was negotiating embraced him and wept.²³² Even with Bismarck's strategic restraint, however, Prussia had added 4 million habitants and now was a truly great power of 30 million.

The case of Bismarck reveals a number of important insights about foreign policy and, potentially, international relations. First, Realpolitik is predicated on both foreign policy egoism and rational thought. It has a set of psychological preconditions. Where rational thinking is not present, one cannot expect to see Realpolitik. Bismarck's epistemic motivation led him to fundamentally different conclusions about proper Prussian foreign policy, even where he shared the aims of his conservative patrons and allies in his own country. Whether it be the willingness to consider distasteful allies or the need to contain ambitions in the face of victory, his rationality was decisive. Second, Realpolitik is rare even where it should be the most prevalent. Bismarck departed from almost all of his colleagues not only in defining Prussian interests egoistically, but also in pursuing those egoistic interests through deliberation and objectivity. (Table 1 summarizes the findings of the empirical section.) Nevertheless, two main potential objections must be considered.

One objection to the account above might be its use of Bismarck's own recollections and thoughts about his thinking style and rationality. It might be argued, however, that everyone understands themselves in this light, what is known in psychology as “naïve realism.”²³³ Bismarck describes himself as objective and deliberative, but does not everyone? This is particularly concerning when we utilize retrospective judgments such as memoirs. Sources capturing thought processes at the moment of decision suffer from less such bias. Using the latter method, however, runs the risk of judging a more general dispositional characteristic from decisionmaking in a few contexts. My solution is to rely on both. Assessments of an individual's overall thinking style are necessary to establish epistemic motivation as a general, dispositional trait independent of behavior that leads to instrumentally rational behavior. We see the same tendencies at play in specific instances, however. I have also tried to mitigate these problems by relying on the perspective of others, both Bismarck's contemporaries and later historians, in judging his rational thinking.

One might dispute the findings of the case, casting doubt on Bismarck's rationality. After all, Bismarck did not demonstrate much strategic restraint after the defeat of Napoleonic France that brought about the final step in German unification. He annexed Alsace and Lorraine and pushed for King Wilhelm to be crowned emperor of the new Reich in France's own Hall of Mirrors at the Palace of Versailles, setting the stage for a war of revenge in 1914 that would kill more than any war in history to that date, with little gain for either side. Historians have also noted that Bismarck had a fierce temper. Many historians maintain that he was an emotional hothead who struggled to keep his feelings in check and was prone to depression.²³⁴ This, however, is completely consistent with the argument offered here—that rationality is hard, that it is therefore a matter of degree, and that it should not be assumed to be the standard (perhaps it is not even common) in international relations.

What distinguished Bismarck from those with whom he did battle, both at home and abroad, was his self-conscious understanding of his own emotions and his efforts to control them, even if not always with success.²³⁵ Recall that rational thinking is thought to be a check on emotional impulses and preconscious intuitions that everyone has. Some, however, seem to be better at what is called “emotion regulation,” which is the ability to explore how individuals work to control “which emotions they have, when they have them, and how they experience and express these emotions.”²³⁶ Even so, Bismarck's behavior was likely not always rational. But if Bismarck was not rational, then who is? We are led to the same conclusion. It is unreasonable to assume Realpolitik and rationality as standard behavior among foreign policy leaders.

I have demonstrated that Bismarck was in many ways sui generis.²³⁷ Despite his successes, he never had a true following of those who thought like him. Many basked in his triumphs after the fact, but they were not like-minded. What if someone who does most things right in realists' estimation is profoundly rare, as his case suggests? What can one man tell us about realist theory? At lot if that man is Bismarck, seeing as he comes as close to a pure realist practitioner as perhaps anyone else in world history. It is precisely his status in foreign affairs that makes his uniqueness so momentous for realist theory.

The implications of Bismarck for international relations depend in part on whether realism is understood as a theory of foreign policy or one of international relations, a source of contention between realists and others but also among realists themselves.²³⁸ Many structural realist scholars have offered realist theories of foreign policy, arguing that neorealism should be capable of making predictions of behavior at lower levels of abstraction than the international system.²³⁹ If there are indeed constraints of anarchy and power pushing and shoving foreign policy-makers, rewarding them for successes and punishing them for failures, then Bismarck should not be the exception in foreign policy practice; he should be the rule. Realist theory suffers in predictive ability if there are few realists in practice. If structural realism can generate a broadly universal theory of foreign policy, then Bismarck, who was eventually awarded the title of prince, should be just another man. This is not true of course. He was a Machiavellian prince among men. Classical realism is implicated, too. As seen above, even as classical realists complain of the lack of rationality and realism in leaders, they simultaneously claim the universal applicability of their arguments, a tension that a number of scholars have noted.²⁴⁰ As a theory of foreign policy, therefore, realism would need to confine its scope to a limited set of instances in which leaders think rationally and conceive of their interests egoistically. Even if systemic forces are present, only rational, objective, and deliberative leaders will assess the structural constraints faced by their states and act accordingly. Rational thinking, based on objectivity and deliberation, is a necessary condition for Realpolitik.

My argument is, however, potentially compatible with neoclassical realist theories of foreign policy. As I have argued elsewhere, neoclassical realism can be understood as a theoretically coherent and logical extension of neorealism that allows for more precise expectations about foreign policy practice.²⁴¹ Neoclassical realists make less generalizable and universal assumptions about foreign policy, offering a more contingent approach drawing on variables from the state-society level of analysis, including culture and domestic institutions.²⁴² States that act as unitary actors with leaders who see the environment free of ideological bias will behave in a more instrumentally rational manner. For this, they will be rewarded by the system. On the other hand, states in which domestic politics allows rent-seeking groups to intrude into the policy-making process and “hijack” the state or in which leaders are biased against an accurate assessment of their environment and interests by ideological blinders such as the “myths of empire” should pursue less instrumentally rational behaviors and be punished by the system.²⁴³

My argument about Realpolitik could be seen as an effort consistent with the neoclassical realist project, one that grounds potential departures from or compliance with the dictates of the system in a lower level of analysis. Realpolitik, as I have argued, identifies the national interest in egoistic terms, which is another way of saying that the entire country is served, rather than some narrow portion thereof. It also presumes an absence of ideological bias, which is truer of some statesmen than others. The implication is clear and testable. Those who possess a rational thinking style and a statist approach to defining their country's interest will be more successful in international politics. Epistemic motivation varies along a continuum. All else equal, it should be associated with achievement, although in an environment of incomplete information, luck always plays a role.

The implication of my argument for an understanding of realism, particularly structural realism, as a theory of international relations (as opposed to foreign policy) is less clear. Waltz famously quips that his neorealist approach cannot explain any particular instance of foreign policy-making and, by implication, the degree of Realpolitik of any statesman. It focuses on broad patterns of international outcomes and the nature of the international system. In the most extreme variant of this argument, neorealism does not presuppose any Realpolitik practice at all. It only expects that states foolish enough not to act egoistically and rationally will suffer the consequences. The system warned you. My argument that rationality is an imposing cognitive standard serves this account in the sense that a lack of objectivity and deliberation could impede learning the lessons provided by the system's feedback. This would be a realist world without realists, close to what Mearsheimer accuses Waltz of providing.²⁴⁴ Although this formulation might seem implausible, there are reasons to think that a world composed of powerful, egoistic states led by decidedly nonrational individuals would be even more dangerous than one composed of rationally led states. Seemingly paradoxically, such an environment would both highly incentivize and highly reward Realpolitik.

My argument about the rarity of Realpolitik also has important implications for scholars' prescriptive efforts. Most obviously, it cautions leaders not to overstate the rationality of the adversaries or others with whom they are interacting. Although this advice seems trivial, it is constantly violated. Even as observers insist that North Korean President Kim Jong-un, or other U.S. rivals, are irrational, they simultaneously assume that these same adversaries will respond in a highly utilitarian manner to U.S. costly signals and back down following a credible signal of U.S. resolve and force. It is an open question whether President Kim or others are in fact rational leaders, but good policy requires a well-considered judgment on the matter and an appropriately matched policy. Realist advocates of restraint understand this, at least implicitly, cautioning U.S. policymakers, for instance, not to overstate the ability of the United States to secure its most favored outcome, given the powerful emotional force of nationalism in countries that are otherwise no match for American power.²⁴⁵

Scholars' policy prescriptions generally target their own leaders, whose thinking might also depart in significant ways from rationality. It is common for realist scholars, even those whose theories expect foreign policy of a Realpolitik variety, to lament the irrationality of U.S. foreign policy and offer rational, realistic alternatives. Their prospects of success seem particularly low in light of the argument offered here. Nonrational U.S. foreign policy might be a function of distorted domestic politics such as capture by domestic lobbying groups or the prevailing liberal ideology guiding this foreign policy.²⁴⁶ It might also reflect the nonrational psychology of leaders, however. To the degree that this is true, one should not expect to persuade leaders easily by recourse to rational means such as reasoned debate and information updating.

No one knew all of this better than Bismarck, who should serve as a model for any modern-day realist. When he wanted to push Wilhelm I in his direction, he did not appeal to strategic necessity but rather to the king's sense of honor, as he knew this guided the king. Bismarck was also keenly aware of the role that emotion played in the decisions of his counterparts abroad, and he sought to manipulate those emotions to get what he wanted, such as by provoking France into a final showdown in 1870.²⁴⁷ He made not just use of material power, but exploited prevailing norms at the time.²⁴⁸ He avoided emotional provocations when they would be detrimental to Prussian interests, such as when he deliberatively avoided generating animosity and hatred following Austria's defeat in 1866 by exercising strategic restraint. In this way, the best realist is a rationalist who understands the power of nonrational impulses.

The author would like to thank the Center for International Studies at the University of Southern California and the DAAD (Deutscher Akademischer Austauschdienst) for supporting this project. He is also grateful for comments from audiences at the University of Birmingham, Dartmouth College, and the University of Oxford. Nina Srinivasan Rathbun also provided extensive and invaluable feedback.