In a famous passage in Perpetual Peace, Kant claimed that even a race of devils could live in a stable, peaceful, and law-abiding state, provided it had a constitution that checked each devil's unbridled self-interest by the self-interest of the other devils. As rational calculators, they understand the utility of general laws; as devils, they secretly intend to exempt themselves whenever they can get away with it. Hence the need to pit devil against devil to keep each other in check. This, Kant tells us, is a purely technical problem, and rational devils will solve it.Footnote ¹ To international relations (IR) scholars, Kant's conceit will sound familiar or even obvious. IR realists who model state behavior through rational choice theory treat states as if they are Kantian devils. Balance-of-power politics offers a concrete example of the diabolical solution of keeping the peace by pitting interest against interest. Moral virtue has nothing to do with it, and to IR realists the vocabulary of virtue has no place in political science.

Like IR realists, international lawyers seldom talk about virtue. Virtue-talk sounds soft and squishy and quaint—suitable for press releases and high-sounding preambles, but not for serious work by serious people. “If you want to know the law and nothing else,” Oliver Wendell Holmes famously wrote, “you must look at it as a bad man, who cares only for the material consequences which such knowledge enables him to predict, not as a good one, who finds his reasons for conduct, whether inside the law or outside of it, in the vaguer sanctions of conscience.”Footnote ² Holmes's bad man is a Kantian devil, and lawyers are by and large instinctive Holmesians. Lawyers traffic in legal rules and their material consequences, not in Sunday school lessons on virtue and vice.

But can we really expect a lawful international order from a race of devils or bad men? Kant to the contrary, it seems unlikely. Perpetually policing all the other devils is too costly for a devil to do on his own; even devils need allies to share the burdens, agents to whom they can delegate monitoring and enforcement, and leaders to coordinate the efforts. In short, Devil World needs guardians, but who guards the guardians? If it is other devils, their problem has not been solved; it has only been replicated. Somewhere, somehow, the devils need to find allies, agents, and leaders who are not devils—guardians with virtue. A world without virtue is a world without trust, and a world without trust is doomed.

Lawyers steeped in the “bad man” theory should absorb the same lesson. Even Holmes insisted that practicing law “tends to make good citizens and good men”; if it did not, clients could never trust their lawyers.Footnote ³ Holmes's own ethical system, in judging and in life, extols duty for its own sake. Holmes had quirky ideas of what the virtues are, but he never doubted that the guardians must be virtuous.

Jan Klabbers agrees. Virtue in Global Governance offers a welcome argument that for the “guardians” of global governance—his examples are statesmen, international prosecutors and judges, mediators, and leaders of international organizations—virtue matters. It matters not only for its own sake, but also for succeeding at their jobs. Drawing in part on some of his earlier articles, Klabbers examines global governance through the lens of contemporary virtue ethics, as applied to the men and women who govern. His wide-ranging chapters include a critique of the state-centeredness of legal and IR scholarship, an exposition and defense of virtue ethics, a jurisprudential examination of why even a rule-based order requires intellectual virtues that cannot be captured in rules, and trenchant case studies of the virtues and vices of leaders in action. In every section of his argument, Klabbers displays an impressive command of the relevant literatures—legal, philosophical, and historical—and he draws on his sources judiciously, picking out the ideas that make the most sense and weaving them into a cogent argument. This is, in short, an excellent book.

Early on, Klabbers recognizes that he has an intellectual obstacle to overcome: the state-centrism common to both IR analysts and international lawyers, which ignores the role of individuals and their virtues. Against this dogma, he reminds us that states are abstract artificial entities (p. 66), and that “the centrality of the state is assumed rather than explained and often symbolized in catchwords (‘Westphalia,’ ‘sovereignty,’ ‘territorial state’)”; he warns that “this ontological premise has the result of foreclosing other avenues of research” (p. 59).Footnote ⁴ In particular, it forecloses discussion of virtues and vices, because artificial entities like the state have neither. Klabbers recognizes that some scholars do admit non-state actors into their ontology, but these too are organizations, or in some cases “structures,” rather than individuals. Like states, structures and international organizations have no virtues or vices—no soul to damn or body to kick, as Thurlow said of corporate persons.

Klabbers identifies several reasons for the statist ontological prejudice of IR realists. Individuals are hard to study; states are “a manageable unit of analysis” (p. 62). Furthermore, focusing on individuals may sound like a return to discredited “great man” theories of history, a relic of romanticism. The romantic “hero-in-history model” can generate good stories but not generalizable data (p. 63). To hard-nosed positivists, then, focusing on individuals would take the science out of political science.

As for international lawyers, the “law of nations” is built on the legal fiction of personified states. Klabbers notes that when individual human beings appear in international legal discourse, it is mostly as stylized personae: “the victim of atrocities, the investor, the war criminal” (p. 61). The state remains the central focus. It is a convenient legal fiction, like corporate personhood in domestic law, but a fiction nonetheless that ignores the decision makers who are the actual actors animating the fiction.

Klabbers clearly does not propose returning to “great man” theories, with all their baggage. His working assumption is more modest: “the character of political leadership plays a role in the conduct and management of international affairs” (p. 67). He admits that his assumption is no more provable than state-centrism, but it seems plausible enough.

A critic, however, might complain that Klabbers leaves unsaid how large a role leaders’ character plays in international affairs. Magnitude matters. If his claim is merely that character plays a real but minor role in the conduct of international affairs, few would deny it, but the claim will not persuade state-centric scholars that they have chosen the wrong unit of analysis. If the claim is the strong one that character matters greatly, it needs more evidence than the examples Klabbers offers to motivate his thesis and make it plausible.

To illustrate the problem using one of Klabbers's own examples (pp. 66–67), Barack Obama and Donald Trump have radically different characters. Trump's character no doubt played a role in decisions like withdrawing from the Paris Accords and the World Health Organization, launching a trade war with China, insulting allies, and proposing to buy Greenland. Klabbers invokes the example to show how plausible his assumption is that leaders’ character makes a difference in foreign affairs. But how much did overall U.S. foreign policy change between administrations? Not much, some might say; Trump's was not even the first U.S. effort to buy Greenland, which the foreign policy establishment (“The Blob”) has long recognized as a U.S. strategic interest.Footnote ⁵ Is foreign policy driven by the president, The Blob, or geopolitics? Even accepting that presidential choices matter in foreign policy, are the president's choices driven more by his character, his ideology, or domestic politics? Klabbers does not say enough to answer questions like these. In Trump's case, one might speculate that insulting allies was a matter of character, pulling out of the Paris Accords was ideology, and proposing to buy Greenland was a political stunt to titillate his base.

At the end of his book, Klabbers commits only to the weak claim: “Character may not matter a great deal in global governance and international affairs—but it does matter” (p. 266). I would have preferred that he left open the question of how much character matters, because it is possible that character matters a great deal. For example, authors in a recent anthology on integrity in international justice make a strong case that the character of prosecutors and judges plays a large role in the success or failure of the enterprise.Footnote ⁶

These are minor complaints, however. Klabbers's critique of state-centrism is compelling, and his assumption that character matters is facially far more plausible than the claim that it is irrelevant. Realistically, every theorist begins with assumptions; Klabbers is more forthright than many in admitting it. What matters more is what he does with the assumption. Let us turn, then, to virtue ethics.

The past century's philosophical literature commonly distinguishes three main approaches to ethical theory: deontology, consequentialism, and virtue-based (“aretaic”) theories, each of them with many variations. No doubt the distinction is too pat, but it derives naturally from the structure of human action, which consists of an actor, the act itself, and its consequences. Each family of theories turns its spotlight on one of these elements. Deontological theories focus on the act itself, and evaluate its morality by asking whether it accords with duty and rules. Consequentialist theories judge morality by whether the act's anticipated consequences are better than the alternatives. And virtue ethics evaluates the act by asking if it is what a virtuous actor would do.

The lines between these need not be sharp. Shining a spotlight on one of the elements of action does not require leaving the others in the dark, and Klabbers argues that none of the three approaches is self-standing (pp. 101–04). Intuitively, virtue ethics is at its most compelling in settings where consequences are hard to calculate and duties pull in more than one direction. That is when we count on the actor's prudence, judgment, and uprightness to make the best of a messy situation—and, even more to the point, we often judge that an act is the morally best one because it is the one the prudent and upright actor would choose.

As Klabbers notes, the virtue ethics tradition originated with Aristotle, but in the early twentieth century it was temporarily “snowed under by deontological and consequentialist approaches . . .” until a mid-century revival (p. 95). Today, it is a thriving field in philosophy and psychology, and it has spread beyond the study of ethics: the currently hot field of virtue epistemology investigates the virtues that conduce to knowledge and the vices that defeat it, and theorists such as Lawrence Solum, Colin Farrelly, and Iris van Domselaar have pioneered virtue jurisprudence that focuses on the character of judges—a theme in Klabbers's criticism of U.S. Supreme Court Justice Brett Kavanaugh's performance at his confirmation hearing, in which Klabbers finds a disturbing lack of judicial temperament (pp. 29–33).

Aristotelian virtues and vices are character traits, understood as dispositions to act in certain ways. Thus, for example, the virtue of courage is the disposition to master one's fear and remain steadfast in the face of danger. He classifies some of these traits, like courage and justice, as virtues of character, and others, like practical wisdom (phronēsis), as intellectual virtues. Virtues on Aristotle's account are not static abstractions but functional excellences: “every virtue causes its possessors to be in a good state and to perform their functions well” (N.E. 2.6. 1106a23–24).Footnote ⁷ And, for Aristotle, their overall function is to promote human flourishing (p. 89).

Over the centuries, philosophers have devised many lists of virtues. One can dispute items on some lists. Must we regard chastity as a virtue, as the medievals did? How about Aristotle's “magnificence” (megaloprepaion), a virtue specific to the ultra-rich that requires them to give generously to the public good, but also to live in splendid houses (N.E. 4.2 1123a7)? What about empathy and compassion? As Klabbers notes, scholars disagree over whether empathy is a virtue in leaders or a source of bias (p. 106).

Other candidate virtues are less controversial. Aquinas names four cardinal virtues, all drawn from Aristotle's list: courage, temperance, justice, and prudence (prudentia is Aquinas's Latin translation of phronēsis). Klabbers's own list of four cardinal virtues for those in public life borrows courage, justice, and prudence from Aquinas, but substitutes honesty for temperance (p. 107).

Klabbers devotes primary attention to the intellectual virtue of practical wisdom (prudence, phronēsis), rightly in my view. Aristotle argues that phronēsis is essential to all the other virtues, including the character virtues like courage and justice (N.E. 6.13 1144b15–17). A person might be naturally fearless, but it takes practical wisdom to distinguish genuinely courageous acts from mere foolhardiness or recklessness; so too, someone might have a natural desire to be just, but it takes practical wisdom to discern what justice requires in a particular case.

Importantly, for Aristotle we cultivate the virtues through imitation and habituation, not through theoretical study (N.E. 1.3, 2.4, 10.9). That is true of practical wisdom as well: it is not the same as theoretical knowledge, and Aristotle repeatedly reminds his students that they will not acquire phronēsis or any other virtue by listening to lectures about it. Klabbers takes his version of virtue ethics from Julia Annas (pp. 15–17), whose conception of “intelligent virtue” analogizes the virtues to highly developed skills.Footnote ⁸ Exercising skills is intelligence in action, but it is typically done without thinking about it. As Annas argues, this is not a paradox. A great pianist does not have to think about her fingering and phrasing while performing a sonata, but she is not playing by mere reflex.Footnote ⁹ Through years of practice and rigorous self-critique, the intelligence of her interpretation has, so to speak, gone into her fingers.

The same is true about good judgment, the sine qua non of every successful leader, and the most important component of practical wisdom. Judgment, Klabbers says (quoting from Nannerl Keohane), comes from a combination of experience, intuition, and intelligence (p. 80). Not everyone has it; it is “a talent that can only be honed by practicing it, but cannot be taught” (p. 101). What Klabbers means by the latter point is that judgment cannot be taught mechanically by laying down a system of rules for judgment. We would then need meta-rules for how to apply those rules, and meta-meta rules about how to apply those, in an infinite regress of rules (id.).Footnote ¹⁰ Eventually, we must judge directly, without the mediation of rules. Klabbers should not be read as denying that judgment can be trained the way other skills are trained: by imitation, coaching, practice, trial and error, and habituation.

It is tempting to treat good judgment and practical wisdom as synonyms, as one recent translator of Aristotle's Ethics does, but I think it makes more sense to recognize good judgment as only one component of practical wisdom. To it one should add curiosity, attentiveness to what others are saying, powers of observation, self-control and self-knowledge, reasoning ability, focus, memory, and doubtless other intellectual abilities and dispositions. (Aquinas, for example, includes the ability to take advice from others among the components of prudentia.) Nevertheless, good judgment lies at the heart of phronēsis, and Klabbers is right to give it pride of place.

The concept of judgment plays another vital role in Klabbers's argument, namely his response to the objection that law is about rules, not virtues—a critique that he traces back to Grotius's disavowal of Aristotle's ethics (p. 124).Footnote ¹¹ Klabbers reminds us that even in a system of rules, every stage of rule application requires human judgment that cannot be reduced to rules. For one thing, rules do not apply themselves (p. 38). As Holmes put it in one of his most famous opinions, “General propositions do not decide concrete cases. The decision will depend on a judgment or intuition more subtle than any articulate major premise.”Footnote ¹² The “articulate major premise”—the legal rule—cannot yield a conclusion without a minor premise displaying the particular case as an instance of what the rule regulates.Footnote ¹³ The minor premise is what Holmes calls the “judgment more subtle,” and no rule dictates that judgment, on pain of finding ourselves in an infinite regress of premises.

As Klabbers points out, choosing the right major premise also requires judgment: rules have exceptions, and we must judge whether the case falls under the rule or an exception (pp. 38–40). More generally, rules sometimes conflict, and when they do we must judge which rule is more pertinent (pp. 45–46, 49–51). And, of course, sometimes legal rules incorporate broad standards of reasonableness, or proportionality, or appropriateness, or “public morals,” that require irreducibly discretionary judgments in particular cases (pp. 42–45).Footnote ¹⁴ For that matter, courts sometimes decide cases equitably, rather than by rigidly applying rules (p. 74). It was Aristotle who introduced the conception of equity as “rectification of law insofar as the universality of law makes it deficient” (N.E. 5.10 1137b26). That too requires the good judgment necessary to recognize that in a particular case the letter of the law would lead to an unjust outcome (N.E. 6.11 1143a20–30).

These are all familiar jurisprudential arguments, but Klabbers is not wrong to remind readers of them, and he puts them together in an attractive and intuitive way. His point is that every rule-based legal order rests on a bedrock of particularistic human judgments that do not themselves rest on rules, but rather on the phronēsis of those who tender them.

Klabbers, like all virtue ethicists, emphasizes that what counts as virtuous depends crucially on the context in which the virtue is or is not exercised. Virtue ethics will sound vacuous until we see how it works in particular cases, and Klabbers provides a fascinating mix of case studies, spanning major leadership roles in global governance. Some readers will find these the most rewarding parts of the book: they are imaginatively chosen and very interesting. However, whether they prove the value of virtue ethics is not always obvious.

Consider his first case study, of Risto Ryti, Finland's president at a crucial moment in 1944. At that time, Hitler had 150,000 troops deployed in Finland, which Finland's military leadership thought were essential to ward off Soviet conquest. To keep the German troops there, Ryti gave Hitler his personal word that Finland would not make a separate peace with the USSR without German permission. This was his creative, and perhaps desperate, solution to a conundrum. It was clear by then that Germany would lose the war, so Ryti wanted to avoid committing his government to a pact with Hitler that would damn Finland in the eyes of the victorious Allies. Ryti thought that his personal promise, unlike a treaty, would not bind his successor. He soon stepped down from the presidency, and his successor took Finland out of the war, as Ryti intended. Klabbers believes that Ryti knew he would pay a heavy personal price for his diplomatic shenanigans, which among other twists required him to deceive the Finnish parliament (p. 183). Sure enough, Ryti was tried in Finland after the war and drew a ten-year sentence.

Klabbers credits Ryti with saving his country from Soviet “enslave[ment]” (Klabbers's word) while sparing it from disastrous association with the Axis. He thinks Ryti's act was not only politically savvy, but also displayed the virtues of courage and generosity, “informed perhaps by a considerable dose of patriotism” (p. 182). (“Generosity” is an odd word choice, but perhaps there is no better name for the virtue of being willing to take blame and punishment on oneself for the sake of one's country.) If Klabbers has understood his motives rightly Ryti's maneuver does seem like a courageous and virtuous act. The trouble is that Klabbers tells us too little about Ryti's life and personality to know whether this episode was “in character” or “contra-character.” This matters to the book's overall argument. Klabbers argues that a virtue-based analysis “may help us understand why certain agents acted the way they did” (p. 172). It will not, however, unless we know whether Ryti had the virtues in other contexts and at other times. Virtues, recall, are dispositions to act in certain ways, and most virtue ethicists believe that to count as a disposition a trait must be cross-temporally and cross-situationally robust. Put in other words, Klabbers makes a good case that Ryti's act was virtuous, but not that he had a virtuous character that played a causal role in his decision. The act itself is overloaded with moral murkiness, and as I explained earlier, one of the strengths of virtue ethics is that in murky situations we sometimes judge that a choice is best because we trust the virtue of the person making it. Without knowing the person's character, however, that pathway is closed, and we must judge the act on its own merits—as Klabbers seems to, without noticing that he is no longer using virtue theory to explain why Ryti acted the way he did in this moment of crisis. If Klabbers's point is that the vocabulary of virtue seems like the best one to describe Ryti's conduct, it is hard to disagree; but if virtue theory is meant to explain the conduct as well as describe it, we would need to know that Ryti displayed a courageous, generous character throughout his career.

Consider a second case study, International Criminal Tribunal for the former Yugoslavia (ICTY) prosecutor Carla del Ponte's decision not to investigate alleged North Atlantic Treaty Organization (NATO) war crimes in Kosovo. Prosecutor del Ponte is renowned for her fearlessness in going after powerful miscreants, most famously the Italian Mafia, who assassinated her fellow prosecutor and tried to assassinate her. In an interview, she declared her willingness to go after NATO forces if necessary, much to the displeasure of NATO members.Footnote ¹⁵ The question is why she did not.

Louise Arbour, del Ponte's predecessor as ICTY chief prosecutor, had formed a commission of experts to investigate accusations against NATO, and del Ponte followed their recommendation not to open investigations. The trouble was that it was a deeply suspect recommendation; the commissioners went through contortions to exonerate NATO.Footnote ¹⁶ The commission's standard for investigation set a very low bar: did available information “tend to show that crimes within the jurisdiction of the Tribunal may have been committed by individuals during the NATO bombing campaign?”Footnote ¹⁷ The two most prominent cases involved bombings that killed civilians (pp. 186–87). One was a bomb dropped on a railroad bridge which struck a passenger train that had unexpectedly emerged from a tunnel after the bomb was released—after which, inexplicably, the aircraft circled back to drop a second bomb, which also struck the train (which was obscured by smoke from the first blast). At the very least, the second bomb run was profoundly reckless: the pilot and weapons officer knew that the wounded train must be somewhere on the bridge. The other bombing destroyed a civilian radio-television station (RTS); NATO claimed it was dual use, but British Prime Minister Tony Blair had publicly stated that the real reason for taking out the RTS building was that it was broadcasting propaganda without giving Western media equal time.Footnote ¹⁸ If the latter, the commission concluded with masterly timidity, the bombing's “legality might well be questioned by some experts in the field of international humanitarian law.”Footnote ¹⁹ Whether or not these incidents were war crimes, they clearly warranted investigation under the commission's professed standard. Yet del Ponte did not investigate.

Klabbers's explanation rings true: she was concerned that if she investigated NATO countries, their support for the ICTY might weaken, with potentially fatal results for its mission (pp. 188–89). His conclusion: “The virtue ethicist might, all things considered, come to just about praise del Ponte's decisions”; she displayed practical wisdom, even if “she acted with less political courage than perhaps is desirable” (p. 189). Notably, though, he also observes that a consequentialist might reach the same decision. Perhaps his point is that practical wisdom requires attention to consequences, which is certainly true. But one might also conclude that virtue theory plays little or no explanatory role in this case study, since del Ponte's well-known courage is precisely what she did not exercise.

One other case study raises a different, and fascinatingly complex, set of issues. Klabbers makes no secret of his dislike of the International Monetary Fund (IMF)—“a global loan shark and agent of economic coercion” (p. 82); and his case study of IMF directors dwells on the fact that “three recent incumbents have all faced criminal prosecution in their home countries, albeit for different reasons” (p. 215). Klabbers diagnoses a set of vices shared to greater or lesser extent by all three: arrogance and entitlement, ruthlessness, and a certain louche attitude toward conflicts of interest. He conjectures that better leadership might help restore the IMF to the “public good conception” that its “original mandate was supposed to achieve” (p. 83). The complex issue is that “some positions in global governance might attract people with particular personalities: alpha (fe)males with strong drives and fierce ambition” (p. 223). Indeed, those qualities might be essential to getting and retaining power (pp. 216, 218), which raises many questions. Can traits that are vices in one context be functioning excellences—virtues—in others, such as getting and retaining power? Can someone with the “strong personality and burning ambition” (p. 223) that Klabbers thinks is necessary to become a leader turn down the volume and do the job well, or will their character flaws spill over and catch up with them? If only a shark can get to the top in the IMF, how much reform can we realistically hope for? A related question concerns the well-known tension between the virtues necessary to run an organization internally, maintaining high morale and a decent workplace, and those necessary to lead its outward-facing mission (pp. 80–82). The underlying issue is whether the tensions between virtues that pull in different directions are manageable. Aristotle believed in a “unity of virtues” thesis—you cannot have one virtue without the rest—but Klabbers rightly rejects the thesis, and understands that virtue is as fragmented as the multifaceted world in which it operates.

These are tough questions that any plausible virtue theory will need to answer. Klabbers does not pretend to answer them all, only to argue that anyone who cares about global governance must ask them. In this I am sure he is right, and his book is a fine place to start.