But among the traits characteristic of the human being is an impelling desire for fellowship, that is for common life, not of just any kind, but a peaceful life, and organized according to the measure of his intelligence, with those who are of his kind … Stated as a universal truth, therefore, the assertion that every animal is impelled by nature to seek only its own good cannot be conceded.

—Grotius, On the Law of War and Peace¹

In the twentieth century … there has been a retreat from the confident assertions … that the members of international society were states and nations, towards the ambiguity and imprecision on this point that characterised the era of Grotius.

—Hedley Bull, The Anarchical Society

I. Bringing the Tradition into the Modern World

The Ciceronian / Stoic tradition gives the world of international relations some valuable concepts and ideals, and the general outline of a world in which all the activities of individuals and governments should be constrained by respect for humanity. But these ideas need further development if they are to provide direction for the modern world, which in many respects has a different shape from the world the Greeks, Stoics, Cicero, and Seneca knew. The Greeks worked with the city-state as the basic unit, the Romans with the expanding reality of the Roman Empire. None dealt with the modern reality of separate nation-states.

The tradition’s core idea that the world is regulated throughout by moral law, and not simply by considerations of expediency, was radical in the time of the Stoics, since previous philosophical views had suggested that we have no moral obligations to those who live outside our own city. It was radical still in the early modern world, when views of the amoral nature of international politics were already dominant, and Hobbes would soon defend the proposition that only a sovereign can put an end to the “state of war” that otherwise obtains between human beings. And it is radical today, when considerations of national security still dominate most nations’ thinking about dealings with other nations and individuals. It is radical today, when neo-Hobbesian views are still dominant. How to make sense of it, then, in our time, and in our world of separate nation-states?

The tradition also leaves modern thought with some great problems, and two in particular. First, it leaves us with the puzzle of how to understand the role of the republic (or the nation) in the moral life of human beings, in relation to the duties we have to respect all humanity: should our fellow citizens take priority in our thought about justice and material aid, and, if so, how and to what extent? Second, Cicero’s inadequate reflections about material distribution leave the tradition with the challenge of dealing with material and economic inequalities between nations, which threaten the very conception of a “cosmic city” regulated by universal moral law.

Hugo Grotius (1583–1645) takes up the task of bringing the Stoic tradition into the modern world. In his works on the freedom of the seas and the law of war, he draws heavily on the Stoic / Ciceronian tradition, which, for him, exemplifies the humanist ideal that he is attempting to commend to Christian nations. Although his classical learning is extensive and he quotes both classical and Christian authors of many types, it is the Stoic / Ciceronian view that, more than any other, shapes his argument, as he applies the idea of a natural law of respect for humanity to arguments about international relations in both peacetime and war. I shall argue, indeed, that understanding Grotius as the heir to the Stoic tradition gives us insight into the structure of his argument that we do not get if we see his moral outlook as a more diffuse one. In the process of extending the tradition, he makes three salient contributions.

First, Grotius systematizes the tradition, providing it with explicit arguments against an amoralist conception of international relations² and in favor of the idea that international relations should be seen as governed by stringent moral norms. He then goes to work showing how very general ideas of human dignity and sociability can, through intermediate principles, give rise to a determinate conception of war and peace, of property rights, and of the general elements of a world society. In this way, he makes the tradition useful and available to modern international law, whose founder he may justly be said to be.

Second, Grotius at least makes a beginning of the problem of international material inequality, developing out of traditional Stoic materials a new view of ownership that has definite implications for the issue of material aid across national boundaries.

Finally, and most important, Grotius brings the tradition into the world we now inhabit, a world of separate nation-states, each with considerable autonomy, all wrestling with issues of religious pluralism and toleration. To this world he offers a conception that subtly interweaves three elements: (1) recognition of national sovereignty as a fundamental expression of human autonomy, (2) insistence that the fundamental subject of moral and political justice is the individual, who has certain rights no matter where he or she is placed, and (3) the vision of an “international society” that goes beyond and in some ways against traditional international law (ius gentium, the law of nations)—that links individuals, states, and a variety of non-state groups in complicated ways—a society, suffused by moral norms, which nonetheless respects national sovereignty and self-determination. This last contribution has been said by recent thinkers to make Grotius a prescient precursor of the contemporary world, in which we need to imagine international society in a multifaceted and flexible way, aware of tension and ambiguity, and to recognize that the international realm is not constituted by the interactions of states alone, or even only by states plus traditional international law.³

II. States, Pluralism, Autonomy

The age of Grotius, and his own writings, may justly be said to mark the dawning of the Enlightenment, in the sense given that term by Kant: “man’s emergence from his self-incurred immaturity.” Although the Peace of Westphalia, which systematized the modern order of separate European states, was not signed until 1648, three years after Grotius’s death, his era marked the gradual emergence of that system out of tumultuous religious controversy and the bitter conflict of the Thirty Years’ War. The Dutch people were struggling to establish independence from Spanish rule; Grotius’s writings on the freedom of the seas were closely linked to Dutch politics. Later, his own life was marred by the religious strife of the times: imprisoned for his Arminian (heretical) beliefs, he had to be smuggled out of Holland in a trunk, and spent the remainder of his career at the court of Louis XIII of France.⁴

This era marked the gradual emergence of the general idea that human beings are no longer living under centralized theocratic control.⁵ In the Middle Ages, whatever political divisions existed, authority was ultimately based in Rome. The Reformation brought with it the idea of the religious independence of each believer from centralized Church authority. This religious idea, in turn, gave rise, during the seventeenth century, to an idea of political autonomy, the idea that each people has a right to exist under its own self-chosen laws. The idea that diverse religious beliefs should be tolerated within a single state was not a part of the picture until much later, in Europe at any rate.⁶ But the idea that each nation has a right to give itself laws of its own making, including laws pertaining to religion, was becoming increasingly dominant, and, with it, the idea of national sovereignty, the idea that each nation has a right to carry out these aspects of its business without external interference.

But if one holds that legitimate law is in this way made by and for human beings, that even people whom one views as heretics or infidels have the right to give themselves laws and to live in accordance with them, without interference, then one is also holding that human reason is to a significant degree independent of religious authority. For one is saying that even people not guided by God have the right to have their own self-imposed choices respected. And this suggests that the human mind, even without God (or the “correct” idea of God), can arrive at choices, legal and political, that are respect-worthy. When we combine this idea with the idea that in the most important matters we are all bound—or rather, we ought to bind ourselves—by a moral law to which we all have access, regardless of religion, we have many of the ingredients, at least, of the Kantian notion of autonomy, cashed out in political terms. National sovereignty and individual autonomy are kindred and mutually reinforcing ideas.

The idea of moral autonomy is not precisely new: for obviously enough the cosmopolitan tradition of the Greek and Roman world had it already, in the form of an idea of the authority of self-given reason above tradition, custom, and conventional religion.⁷ At Rome, despite some persecution of Jews and Christians, there were also defenders of toleration.⁸ Cicero himself appears to go rather far in this direction, in his correspondence with his friend Atticus, an Epicurean who justified his withdrawal from political life by the tenets of that sect. Cicero, of course, believes in nothing more deeply than the duty we all have to serve the republic; he connects this duty to his philosophical views. But he also respects his friend. In one remarkable letter,⁹ he says, you know, you and I are so close that hardly anything divides us—except for the choice of a way or mode of life (ratio institutae vitae). For me, a certain ambitio has motivated me to serve the republic. In your case, a perfectly plausible set of reasons (haud reprehendenda ratio) has led you to prefer retirement. In this way, Cicero grants that the reasoning of Atticus deserves respect, although he does not share it. Nonetheless, because religion is not the source of division and struggle at Rome that it became in Europe later, and because the major political upheavals of the day were motivated by rather different considerations, Cicero does not develop these ideas of respect and choice very far. Thus, reclaiming ideas of autonomy and associated ideas of toleration after the intervening period of religious domination becomes a new act against new opposition, requiring political forms different from those of the ancient republic.

When Grotius returns to the Ciceronian tradition, he does so, then, in a changed world, one that demands explicit doctrines of self-government and mutual respect if the right of both individuals and peoples to exit from centralized religious authority is to be secured. Moreover, it is obvious that the idea of human freedom was of central importance to Grotius in his own religious conception. The Arminian heresy, for adherence to which he risked his life and endured exile, was the assertion of human freedom against the doctrine of predestination: human beings have the power to determine their salvation by their own chosen acts. His religious treatises consistently express the importance of choice and responsibility.¹⁰ At his trial for heresy, Grotius’s heretical belief in choice was linked to his controversial political doctrines, in particular his defense of the autonomy of each province to legislate on religious affairs.¹¹ Thus it is not surprising that his major work on political philosophy should also give ideas of freedom and sovereignty a central place.

In the Prolegomena to BP, Grotius takes a famous and decisive step. Medieval natural lawyers had of course allowed that natural law could be apprehended by human reason without faith. Ultimately, however, it derives its validity from God and God’s law. Grotius, by contrast, states: “What we have been saying would have a degree of validity even if we should concede (etiamsi daremus) that which cannot be conceded without the utmost wickedness, that there is no God, or that the affairs of men are of no concern to Him.” The fact that this remark is wrapped up in a tissue of pious sentiments, and that Grotius takes utmost care throughout the work to present himself as a deeply pious man (as he probably was), did not cause these bold words to escape people’s notice. Referred to simply as the etiamsi daremus, this argumentative move of Grotius’s became the hallmark for many political thinkers as the Enlightenment dawned. For Grotius, it is not simply that heretical and infidel peoples may happen upon moral truths without being aware of a religious truth that justifies them. The moral arguments that human reason creates and assesses have validity independently of not only the believer’s relation to God, but also the very existence of God. Human morality, supported by freestanding moral arguments, is self-given law.

Grotius connects this idea of validity apart from God with the idea of national sovereignty, to which he attaches great importance. Already in his early work De Iure Praedae (ch. 2), he asserts that separate states are a very important part of protecting and fortifying the society of all human beings. Here in BP, he defines sovereign power as power “whose actions are not subject to the legal control of another, so that they cannot be rendered void by the operation of another human will” (I.3.7.1). He then goes on to insist that there exist many legitimate sovereign states, each of which has the right to impose laws by its own choice:

Just as, in fact, there are many ways of living, one being better than another, and out of so many ways of living each is free to select that which he prefers, so also a people can select the form of government which it wishes; and the extent of its legal right in the matter is not to be measured by the superior excellence of this or that form of government, in regard to which different men hold different views, but by its free choice. (I.3.8.2)

Grotius’s version of this doctrine would not satisfy modern proponents of democratic sovereignty: for he insists that a people has the right to enslave itself, and thus he defends the rights of many actual kings to the virtually unlimited power they exerted. It is impossible to know how far these parts of the work reflect the political pressures under which he lived, as a refugee given a fragile existence at the court of a foreign absolute monarch. But the crucial move is his insistence that the choice of the people is authoritative, whether right or wrong. Superior excellence does not mean a right to impose one’s will on another.¹²

Grotius thus makes it explicit that the fact that a people has customs or religious practices different from one’s own is not a legitimate ground for aggression. He cites Plutarch: “To wish to impose civilization upon uncivilized peoples is a pretext which may serve to conceal greed for what is another’s” (II.20.41). He shortly argues explicitly that waging war on account of religious difference is illegitimate (II.20.44); even stating that infidels have sovereignty, and this sovereignty is to be respected (II.20.44–47). Addressing the contention that we may justly make war, at least, on states who refuse to accept Christianity after it is offered to them, he rejects this contention as well. In De Iure Praedae too (ch. 12), he insists that infidel states have property rights and rights of political sovereignty of which they cannot be justly deprived on the grounds that they are infidel, or on grounds of papal donation. He thus rejects an argument commonly used since the fifteenth century to justify expansionist war—and rejects, as well, the division that argument posits, between a world of Christian states and a world of non-Christian states.¹³ Sometimes, as Grotius’s own life clearly shows, violence against heretics can seem to Christians even more justified than violence against infidels. But his position similarly entails that Christian heretics cannot justly be targets of aggression (II.20.50). The one thing he does grant is that we may justly make war on states that persecute Christians cruelly for the sake of their religion alone (II.20.49)—a point to which I shall return in speaking of humanitarian intervention.

How is Grotius’s view about political sovereignty connected to his general concept of human moral sovereignty? In one way, the two views are obviously of a piece, and the moral doctrine gives support to the political doctrine. For the right of a people to give itself laws, even when we may think the people heretical or infidel, gets a lot of mileage from the idea that important moral and political truths are both logically and epistemologically independent of the true religion. The conception of the human being as a source of valid norms through its own autonomous activity is deeply built into the picture of peoples, and of their sovereignty, that he presents.

Yet we can also see a tension emerging between the two strands of Grotius’s interest in autonomy, and it is a tension that has been with us ever since. On the one hand, a people has a right to choose its laws. On the other hand, law-giving of this sort often oppresses human beings domestically, thus violating the autonomy of individuals. In particular, as the modern human rights movement will insist, there are important moral truths that transcend time and place, giving rise to individual rights, for example, rights of free speech and freedom of conscience. Sovereign peoples often ignore these rights, which may be extremely important to autonomous individuals. Doesn’t full respect for the autonomy of our own moral reasoning require that in central cases touching on core moral values, the individual must be protected against the sovereign, but putatively immoral, actions of a people, ours or another’s? In the name of individual autonomy, may we hold that the sovereignty of a nation has limits?

It is because Grotius’s idea of sovereignty is a moral idea, founded on a moral doctrine of autonomy, that he has this dilemma, which ultimately produces his complex and indeterminate position on humanitarian intervention. If his doctrine of sovereignty were like that of Hobbes, then that would be that: what the sovereign imposes is imposed, and there is no right of resistance, internal or external. But for Grotius, the ultimate source of both moral autonomy, and, through it, political sovereignty, is the conscience of the individual; and the individual may often be in a position to criticize a sovereign regime and may also be victimized by it, for example in matters of religious repression. Grotius is unable and unwilling to turn away from this problem in the Hobbesian manner: international society as a whole stands under moral law, and each individual is both a giver of and subject to that law. Moral sovereignty underwrites political sovereignty, but it doesn’t get altogether absorbed into it. Grotius does not courageously press forward in the defense of individual conscience, as did his seventeenth-century contemporary Roger Williams and the slightly later seventeenth-century thinker John Locke.¹⁴ But he has all the materials of the problem at his disposal. As we wrestle today with the twin pressures of human rights and state sovereignty, so too did Grotius in his era: and the self-conscious complexity of his response may prove a valuable guide to our situation.

III. Natural Law and the World of Sovereign States

Grotius announces that he has been led to defend the claim that there is a moral law linking all nations because of the “utter ruthlessness” (Proleg. to BP 29) he observes in dealings between nations, a shameful and barbarous “lack of restraint” (28). Such behavior derives aid and comfort, he believes, from the doctrine that there are no moral laws or norms appropriate to war, and from the more general doctrine, frequently linked with it, that moral norms, in politics, stop at the national boundary: what reigns between states is simply force and self-interest. These realist doctrines, which have dominated much of our own contemporary thought about international relations, are as old as the ancient Greek world, and Grotius cites a host of classical authorities who endorse them. His own resistance to the amoralist doctrine is modeled on Stoic and Ciceronian resistance to its ancient version.¹⁵

Unlike most of his Stoic forebears, Grotius reflects explicitly about how one may argue for the existence of something as fundamental as the moral law (or “natural law”¹⁶), and for the nature of its specific requirements. He offers two distinct paths to his conclusion. The former he calls “more subtle,” the latter “more familiar.” We may show that something is natural law, first, a priori, that is, by showing that it has a “necessary agreement … with a rational and social nature” (BP I.1.12). Elsewhere he expresses this as the idea that we refer our arguments to “certain fundamental conceptions which are beyond question, so that no one can deny them without doing violence to himself” (Proleg. to BP 39). Second, we may show that the proposition in question is natural law a posteriori, by showing that it is “believed to be such among all nations, or among those that are more advanced in civilization,” and that it therefore expresses the “common sense of mankind” (BP I.1.12).

This latter route, with its questionable distinction between advanced and non-advanced civilizations, is not favored by Grotius himself, although he feels free to use it, and it is never a bad thing, in his view, if this approach can give additional support to the first sort of argument. Part of using the latter route, he makes clear at many junctures, will be to cite the opinions of philosophers, poets, and other cultural authorities—since, of course, that is the only way we have access, over distances of space and time, to the “common sense of mankind.”¹⁷ This appeal to reflective people may also make his notion of “common sense” less like a mere opinion poll and more like the Aristotelian notion of endoxa, the reputable opinions of “the many and the wise.” But it also has the problem that key ethical conclusions are supported by appeal to cultural authority.

Grotius’s method of a priori argument is Socratic: he asks each reader to consider the fundamental concepts of his or her person and their relations, and to judge whether a proposed doctrine does violence to those concepts, or, by contrast, inheres in them. This sort of freestanding moral argument (whether we should really call it a priori or not) is what he very much prefers. One grave defect of the argument from “common sense” is that, as Grotius is well aware, the common sense of mankind often yields wrong conclusions, and embodies a less rigorous moral concern than the conscience of the individual, after reflection on Grotius’s arguments, is expected to yield. For Grotius recognizes a very sharp distinction between the traditional ius gentium, the body of judgments that embody the collective wisdom of the international community over time, and the ius naturale, the moral law that should actually govern the conduct of individuals and states in their dealings with one another. In book II of BP, Grotius lays out in some detail the conduct in war that is and is not permitted by the traditional ius gentium. This standard is very permissive from the moral viewpoint:¹⁸ it holds, for example, that one may kill noncombatants, including women and children, with impunity—although it draws the line at rape. One may pillage anything, including sacred objects. And so on. Then, in a sharp and jolting transition (ch. 10), Grotius announces that he is now going to take back a lot of what he has just said: he will retrace his steps and deprive those who wage war of privileges he seemed to grant them, but did not. He then goes on to lay out the more stringent moral standards implied by ius naturale: many things that may be done with impunity under current standards are morally unjustifiable. He thus reveals to the reader the fact that ius naturale cannot be adequately arrived at by the method of gathering up the common opinions of mankind.

Grotius clearly expects his argument to be cogent to a reader who has grown up with ordinary human understanding. In that sense, even in the ius naturale portion of his argument he might be said to rely on something like endoxa in order to persuade. But it is very important to see that sheer traditionality or widespread acceptance, though it seems weighty from the point of view of his a posteriori method, ultimately has no moral weight for him. What does is each reader’s autonomous Socratic confrontation with the argument. And it is this sort of reflective confrontation that he constructs, in his crucial argument against the amoralist opponent.

Grotius points out, first of all, that human beings are not just beasts, who can and do amorally tear one another limb from limb. We are creatures of a distinctive sort, capable of governing our relations with one another by moral norms. Grotius focuses not so much on reason per se, as on the capacity for moral reasoning and for understanding and living by norms of justice. Citing the Stoics, he links this ability closely to the idea of “sociability”: we are creatures who cannot flourish without interactions with other human beings—and not just any sort of interactions, but a shared life that is peaceful and reciprocal, and organized by intelligence (Proleg. to BP 6). The argument is not simply that we have such desires implanted in our nature. It is, apparently, the idea that these needs and desires have a salience for us when we think about who we are, and about what makes our form of life a distinctive one. We cannot ignore these aspects of our flourishing without doing violence to ourselves. Grotius, like the Stoics, thinks of ius naturale as taking its start from some very basic moral evaluations, and thus, as a nonderivative, or freestanding, moral conception.¹⁹ Think of a life without moral sociability, the argument goes, and you will find that it is not only a life in which the distinctive activities of a human being are absent, but also, therefore, a life that you could not yourself endorse without doing violence to yourself.

From this very basic starting point, Grotius now proceeds to the idea of law. Let us imagine a sociable being, endowed with moral capacities, intending to live in peace with other such beings. Immediately we understand that such a being needs laws in order to construct such peaceful relations. For only rules or laws (Grotius’s concept of ius is very broad, and at this point in the argument encompasses both positive law and binding moral norms) make it possible for beings to be sociable without all the time suffering violence or unjust deprivation at one another’s hands. If we imagine a condition without laws or norms, we imagine the ubiquitous frustration of the human being’s desire for mutual relations that are both moral and social. Such laws, Grotius argues, must do several basic things. They must instruct all to abstain from aggression and theft; they must arrange for restitution of what has been taken by aggression or theft, and for the punishment of the guilty parties; and they must point the way to a fair distribution of property (Proleg. to BP 8–10). Importantly, the law of nature enjoins that agreements are to be honored (pacta sunt servanda): for without such a principle, the whole edifice of law would necessarily collapse (15).

Grotius’s arguments thus have a form similar to those made by Cicero and the Stoics before him and Kant after him. They ask us to see that we cherish a very basic conception of our humanity as both moral and social. They then invite us to consider a world in which some moral institution (promising the rule of law) did not exist. We see, when we consider this world, that it is no better than a bestial world, a world in which what is characteristic of our humanity will meet with continual frustration. For Grotius as for others in the tradition, this thought is supposed to give each person weighty moral reasons to support these institutions, and to abide by their demands.²⁰ And clearly this is a way of thinking about what it is to respect our humanity, not to use it as a mere tool of our own advantage.

Grotius now turns from the intra-state application of these ideas to the relations among states. He emphasizes that most people agree that law exists outside the borders of the state: thus we have a conventional understanding about the existence of a ius gentium, and of what that law involves. Nonetheless, some thinkers hold that justice and law have no proper application in this domain, which is simply a domain of force and violence. Grotius now denies this: just as the citizen who violates his country’s law “breaks down that by which the advantages of himself and his posterity are for all future time assured,” so the state that transgresses the law of nature and of nations cuts away also the bulwarks safeguarding its own future peace. There are thus reasons of efficiency for recognizing and obeying international law; but thinking of how the fulfillment of our sociable nature depends on the existence of stable peaceful relations between peoples gives us a more direct moral reason (18–19). If no association of human beings can be maintained without law, surely that is also true of “that association which binds together the human kind, or binds many nations (populos complures) together”—and this fact gives each of us reason to respect and follow the law in question (23). Again, not to do so is a way of doing violence to our own humanity.

IV. The Law of War: Ius Gentium and Ius Naturale

Grotius begins, then, with a very general conception of personhood that he believes to have deep roots in any interlocutor’s way of thinking. He asks at each stage, Socratically, what institutions and practices do violence to that conception; the interlocutor is then expected to reject them, on pain of doing violence to him or herself. First, he gains acceptance for the general idea of life under law; next, for some intermediate principles, such as non-aggression, non-theft, and the sanctity of treaties and other agreements. Then he argues that these same principles must be recognized in the world outside the state. This world, he now adds, has one further intermediate principle: national sovereignty. For national sovereignty (as he argues most fully in De Iure Praedae ch. 2) is essential to constituting and fortifying the larger society of the human kind. As we have seen, he believes that national sovereignty is an essential expression of human autonomy, that is, in the most literal sense, the ability to give oneself laws of one’s own choosing; putting this, now, into the context of his Socratic argument, we may say that the interlocutor cannot accept a world without sovereign nations, without doing violence to his own deep conception of the human being as moral and sociable.

From these principles, the highly abstract and the intermediate, Grotius proceeds to derive a normative account of conduct in war. As we have seen, the actual ius gentium is very permissive. But, says Grotius, the word “lawful” has two senses: it may just mean “done with impunity”; or it may mean “in accordance with moral law” (BP III.10.1). There is a large difference between the lawful in the first sense and the lawful in the second. Quoting Seneca, he insists that often, “What law permits, the sense of shame forbids to do,” explaining that by “sense of shame” he means “not so much a regard for men and reputation as a regard for what is just and good, or at any rate for that which is more just and better” (III.10.1.2). Justice, he insists, again following Seneca, extends well beyond the current reach of positive law, and imposes more stringent requirements. For we must always recall that “national customs are not to be taken for the law of nature” (II.20.41)—both because national laws often embody particularistic religious requirements that do not apply to all, and because they may simply embody unconvincing or bad moral reasoning, including reasoning designed to feed the greed of that nation and its members (II.20.41). Not surprisingly, traditional ius gentium contains much that derives from national custom and that is therefore defective in one or more of these ways.

We can get a good start toward understanding these stricter requirements by thinking of what treatment is morally permissible toward a human being: as Seneca says (quoting De Clementia I.18), “there is something which the common law of living things forbids to be permissible against a human being.” Thus, whereas the ius gentium permits combatants to do whatever is necessary to attain their ends (BP III.1.2),²¹ ius naturale will consider the respectful treatment that is suited to a human being’s moral and social nature, reminding us of our most indefeasible end, which is to live with one another in a way that befits that nature. This principle suggests the intermediate principle that even in a just war, care should be taken to moderate the killing, and to promote in this way the possibility of a peaceful reintegration after war (III.11). In war, peace and its preservation should always be kept in view, for the sake of “that greater society of states” (maior illa gentium societas). Throughout the ensuing chapters, references to Cicero and Seneca are especially frequent.

Grotius now goes against the ius gentium, in a way that has become formative for modern international law. Everything, he argues, must be done to prevent the deaths of innocent people. Children should always be spared, as should women, elderly men, prisoners, members of religious orders, farmers, merchants, and writers.²² Those who surrender may never be killed. Even among combatants, it is wrong to kill any who fight under compulsion, such as slaves and prisoners. (This principle does not extend to conscripts, presumably because they are not captives and can leave the nation if they don’t want to serve, and because nations have rights of self-defense.) Prisoners of war must be given decent treatment: no bodily mistreatment, no sexual abuse, decent nutrition and health care, tasks that are not so heavy as to cause a danger to health: in short a kind of “perpetual maintenance” (III.14).

Like Cicero, Grotius is particularly concerned with the conduct of victors. Here again, his recommendations are guided by the general thought that the goal should always be the preservation of peace for “that greater society of states” (maior illa gentium societas, III.25). While war is still continuing, he urges the party that has the upper hand to avoid all devastation of the enemy’s land (III.12), and to avoid any assault on sacred objects and places (III.12.7). Such moderation is morally required, but it is also advantageous, because it allows the enemy to envisage a decent life afterward, and thus to avoid despair, which breeds extreme measures (III.12.8). For such reasons as well, innocent civilians are not to be deprived of property more than is absolutely necessary to pursue victory (III.13.4).

At the conclusion of war, Grotius urges victors not to press their advantage too far, but to accept peace on reasonable terms, or even terms that involve some losses (III.25). All killing must stop. Even though it is possible for the victor to assert political sovereignty over the vanquished, both morality and self-interest dictate that this should rarely be done: sovereignty is a profound expression of a people’s autonomy and self-respect, and thus both respect for humanity and concern for future peace suggest that they should not be robbed of it (III.15). (Grotius predates the bulk of European colonizing, but his principles entail that virtually all of it is illegitimate.²³) Peace is best arranged “while each has confidence in himself” (III.25.6). Holding foreign territories as colonies is not only morally problematic, but also a dangerous course, prompting strife in the future (III.15). Even when it is judged that one’s own future safety requires that sovereignty be assumed over a conquered people, it is right to leave a portion of the sovereign power to the people themselves and their own rulers. In short, as much sovereignty and liberty should be left as is compatible with defending one’s own nation from illegitimate aggression. It is particularly important to protect the religious liberty of the conquered people (III.15.11), although the conqueror is entitled to take steps to prevent the oppression of his own religion by that people. In general, Grotius concludes, clemency and moderation are ways of treating a people respectfully and thus building a good future. He quotes from Livy: “If you should have given to them a good peace, then you may expect it to be reliable and perpetual; if a bad one, brief.” And from Cicero: “Let this be a new method of conquering, to fortify ourselves with mercy and generosity.”²⁴

Once made, peace must be kept with the utmost scrupulousness: here the key principle pacta sunt servanda returns again (III.25.7): “[P]eace, whatever the terms on which it is made, ought to be preserved absolutely, on account of the sacredness of good faith, which I have mentioned.” Care should be taken not only to avoid all deceit but even to avoid causes of anger; this scrupulousness is even more important in a peace after hostilities than in an alliance.

Grotius’s discussion of ius naturale is famously ambiguous. On the one hand, he makes a strong case that the moral law requires conduct that is not required by traditional international law or ius gentium; to that extent he would appear to make a case for the alteration of ius gentium. On the other hand, he plainly sees a role for international law as distinct from natural law: for he insists that the requirements of natural law do not change, while there is room for a realm of international law that is more time-bound, containing provisions that may reasonably be altered as conditions of life change (II.8). So how does he see his argument in book III, in its relation to traditional ius gentium?

If ius gentium is more changeable and in that sense narrower than ius naturale, it still ought to be consistent with it. Clearly, Grotius in book III is not merely describing a realm of moral supererogation that is not binding on actors, who are still permitted to violate moral law in ways that are currently allowed by ius gentium. He is talking about binding moral requirements, although he is aware that under current international law these will not be enforced. Is he suggesting that ius gentium ought to change so that these requirements will be enforced? In some cases, it seems likely that this is his intention, veiled behind the tentativeness imposed by his own vulnerable situation. Thus, the requirements concerning the treatment of prisoners and noncombatants are best read as proposals for revisions in international law, and indeed most of them have been so incorporated. There are more general moral prescriptions that cannot be read in this way, however: the advice to pursue lasting peace first and foremost, and the requirement to be merciful. These cannot be translated into positive law, and remain as part of an ethical background that should inform the spirit of international law, which will likely continue to permit things that are not morally normative. There will also very likely remain cases in which international law forbids what the moral law permits: thus, the requirement not to use poison against an enemy might have a good prudential rationale in a particular era, while from the point of view of permanent moral interests a killing by poison does not look very different from any other type of killing.

Thus the world that Grotius outlines is not simple. Although he foresees an evolution in international law, he also projects a world that will continue to contain binding moral norms that are not legally enforceable—or are enforceable only when individual nations turn them into law. The relation between law and norm is intended to be contestable and complex, and Grotius gives us no easy recipe for the future of that relationship.

V. The Individual as Subject: Humanitarian Intervention

Grotius’s theory ascribes considerable importance to national sovereignty, not simply as a practical force with which we must reckon. Sovereignty also has moral importance, as an expression of human autonomy. In Grotius’s view, that importance derives ultimately from the idea of the autonomy of the individual human being. For him as for the cosmopolitan tradition before him, groups are important expressions of human sociality and choice, but they are not in and of themselves loci of choice and do not as such have rights. Sovereignty is important because each person’s choice of a way of life is important; for Grotius in his time, it is above all a protector of religious liberty. (It protects religious liberty, however, for the majority, not for internal minorities.)

Sovereign nations do not always protect the rights of individuals. Often they persecute people on grounds of religion, and deny them various other important prerogatives, which the law of nature would guarantee to them. (And Grotius, perhaps on account of his own delicate political position, does not say, with Roger Williams and John Locke, that natural law requires internal protection of liberty of conscience.) So a dilemma is created for international society and the nations that are its members: how far is it right to intervene in the affairs of a sovereign nation that is violating the rights of its members? Grotius’s discussion of humanitarian intervention, one of the most influential in the history of the topic, and one of the most influential aspects of his book for posterity, grows out of a recognition of this dilemma.

We can appreciate Grotius’s position more justly if we imagine two alternatives to it. One alternative, often associated with Kant, and perhaps rightly found in his earlier writings, though not in Perpetual Peace, would be to argue that individuals and their rights are the only things of real importance. Let us call this the Moral Rights position.²⁵ For holders of this view, national sovereignty is simply a convenient way of organizing the protection of individual rights, and the implementation of measures for upholding individual dignity. It should have no weight when nations or their leaders are violating the rights of individuals. This view would not necessarily license forcible intervention into the affairs of another state any time there are rights violations, for prudential considerations suggest that this would typically be bad for individuals in the long run. But there is no moral barrier to such intervention, at any rate. Such a view leads naturally in the direction of a human-rights-based world government, and a weakening of national sovereignty. It sees nations as at best conveniences; at worst, dangerous obstacles.

Another alternative to the Grotian position would be one according to which the nation-state is the only legitimate rights-protecting entity: rights are artifacts of national sovereignty, and do not reach out beyond the nation. Let us call this the State-Based-Rights view. According to this view, if an individual’s rights are violated, then it is nobody’s legitimate business but that of the nation in which she lives. People have rights as citizens of states, and these rights do not follow them, so to speak, into the realm of inter-state relations, which is typically imagined, by holders of this view, as a realm without rights or moral law, dominated by considerations of national security and interest. This view would not license any form of humanitarian intervention.²⁶

Grotius’s response to the State-Based-Rights view has two stages. First, he will argue, as he does throughout his work, that the realm of international relations is not a realm free of moral norms and binding moral requirements. But one might hold that there are binding moral requirements in the international realm (requirements about the conduct of war, for example), without holding that this realm has any legitimate business dealing with violations of individual rights within a state. One could hold, that is, that the moral norms that govern the international domain are limited to norms pertaining to the relations of one state with other states (in war especially, but also in commerce and other peaceful dealings). Most individual rights might still be envisaged as artifacts of the state, and their protection as the business of that state alone. So Grotius must then argue, further, that the same reasons that should lead us to conclude that the international realm is not in general amoral should also lead us to conclude that individual rights, as well as inter-state relations, exist outside the state and are the legitimate business of the international sphere.

Grotius makes no such explicit argument. And yet, the ideas of natural law and human sociability that are basic to his account of the law of war also clearly entail an international realm governed by a rich picture of morality whose ultimate focus is the individual person. Grotius would clearly think it absurd to accept the idea of natural law for inter-state relations and yet to deny that natural law protects the rights of individuals. The basic idea of the entire tradition within which he argues is that of the dignity of the human person, as a being both rational and social. Restrictions on inter-state conduct are ultimately justified by reference to that norm, and the associated strictures against aggression and fraud. What the law of war does, most ultimately and basically, is to protect human beings from violation. How could one coherently uphold those moral constraints on state action and yet hold that natural law does not condemn violations of individual dignity that are carried out by that person’s own state? Grotius holds that human rights are prepolitical, in the sense that they are grounded in facts about the human being that preexist the state, and that do not cease to exert their claim when the state does not recognize them. So, just as natural law goes beyond the traditional ius gentium, so too it goes beyond the norms and actions of individual states, should those insufficiently recognize or protect human dignity. (Thus Grotius objects to the position of “Victoria, Vazques, Azor, Molina, and others” who hold that the power of punishing derives from civil jurisdiction alone, insisting that it derives from the law of nature [BP II.20.40.4].)

Yet Grotius clearly does not agree with the Moral Rights position. For he gives an analysis of national sovereignty according to which sovereignty itself has moral significance, as an expression of human autonomy. Human dignity and autonomy require the opportunity to live under a government that is in some way chosen by, and accountable to, the people. We may certainly feel that Grotius had too rudimentary a conception of accountability (in that he did not require anything like democratic participation, and thought that people were entitled to enslave themselves to an absolute monarch if they wanted to), and yet recognize that both consent and accountability are important features of his political conception of sovereignty and its moral weight. His picture is not conceptually incompatible with the idea that at some point the people of the world might put themselves under a world state. But his reflections on religious war suggest strong reasons why we might not move in that direction: for the foreseeable future, people will want to protect their own religious freedom by designing a state that does protect it, and this is probably most likely to be realized if there is a plurality of states. As I have mentioned, Grotius favors internal religious toleration as well as religious diversity across states; but he plainly thinks that choice of a way of life will lead to some variety, and that variety has moral significance. Its protection is a part of what it is to protect the moral rights of individuals.

Grotius’s position, unlike its rivals, creates, then, a dilemma. That complexity is its strength. On the one hand, to intervene in the internal affairs of a nation is bad, a violation of the rights of human beings to choose a way of life. Moreover, in practical terms, such intervention, as Grotius repeatedly observes, is more than likely to be motivated by the desire to gain control over that territory and people. Thus to countenance it risks countenancing abuses, and, ultimately, the imposition of colonial power on a formerly self-governing people. He cites Plutarch: “To wish to impose civilization upon uncivilized peoples is a pretext which may serve to conceal greed for what is another’s” (II.20.41). On the other hand, sovereignty plainly ought not to be understood as a license for some people within a nation to tyrannize over others, and thus the very rationale that supports sovereignty also supports strong protection for individual rights.

The tension in the Grotian position is thus not tragic, as it would be if he held that groups have rights in and of themselves, and those rights were in some ways on a collision course with individual rights. Because the moral significance of the nation derives from the moral significance of the individual, it is of a piece with, and coheres well in principle with, the protection of a wide range of rights for individuals. We can easily imagine a regime that is both sovereign and rights-respecting. But in the world of imperfect states that we know, it poses a practical dilemma of considerable moral delicacy. To intervene on behalf of persecuted or violated individuals seems morally required; but it also violates individuals in another way, by violating sovereignty. This is the problem Grotius now addresses in his famous and influential brief chapter on humanitarian intervention (II.20.40).

One defect of Grotius’s discussion that we should note at the outset is its failure to give an adequate account of state legitimacy. His view that people may consent to enslave themselves gives him a more difficult time with the issue of intervention than he otherwise might have, because he grants legitimacy to many types of tyrannies that one might plausibly judge illegitimate.²⁷ Where we are dealing with such a tyranny, intervention seems morally less troublesome than when we are dealing with a regime that meets certain decent minimum standards of participation and accountability.

Another issue that he does not sufficiently consider is that of political inclusiveness. If the moral importance of sovereignty derives from human choice and autonomy, then we need to ask who gets to choose. If women, ethnic and racial minorities, and perhaps others are simply excluded from the act of choice altogether, then the appeal to violated sovereignty seems weak against an intervention that protects their human rights. Grotius devotes no consideration at all to the issue of women’s non-representation, and seems to have little concern for inclusiveness in general.

Within these limitations, however, his discussion is of considerable interest. He argues that intervention is justified when a nation “excessively violates the law of nature or of nations in regard to any persons whatsoever.” This right belongs to the sovereign, not to private citizens, who might otherwise excessively take the law into their own hands. (Grotius is in general opposed to all forms of private warfare.) Intervention is permissible, not (apparently) morally required in such cases, but it is praiseworthy: Grotius cites the examples of Hercules and Theseus, who assumed risks to help people in other parts of the world. (Diodorus says of Hercules, “By slaying lawless men and arrogant despots, he made the cities happy … He traversed the world chastising the unjust.”)

Grotius cautions that national custom is not to be understood as equivalent to natural law, though people often confuse the two: thus the fact that another nation does not observe one’s own national customs does not license intervention (II.20.41); nor does the fact that they do not observe one’s own religion and its divine laws (II.20.42). Moreover, even when we deal with natural law, we should distinguish between general principles that are pretty obvious and incontrovertible, and particular applications, which are likely to be more controversial (II.20.43). Even if we are convinced of our own position with regard to one of these concrete matters, we can see how another nation might sincerely have reasoned differently, and we should view that case as one where ignorance of the law excuses the violator (II.20.43). Moreover, we must again remind ourselves that wars ostensibly undertaken on moral grounds may always be suspected of being really motivated by considerations of power or profit, and thus we should not undertake them “unless the crimes are very atrocious and very evident.”

What are the crimes that may license humanitarian intervention? Grotius at this point has recourse to a list of remote classical examples, beginning with Alexander’s punishment of the Sogdianians for impiety against their parents;²⁸ Grotius is euphemistic here, since the text of Plutarch to which he refers specifies that they systematically killed their parents in order not to have to take care of them in their old age. Next, he refers to the practice of cannibalism, opposed by Hercules, and to the practice of piracy. All these are described as the deeds of “barbarians, wild beasts rather than men.” So this gives us a general sense of the terrain of the exception. A learned footnote expands further, mentioning Justinian’s intervention with the practice of castration of male children, and the way in which “The Incas, kings of Peru, forcibly compelled the neighbouring peoples, who did not listen to a warning, to abstain from incest, from the intercourse of males with males, from the eating of human flesh, and from other crimes of that kind.”

If we are inclined on first reading to think that Grotius offers too narrow an account of humanitarian intervention, especially when he omits religious persecution and other common violations of basic human rights, these fascinating examples may make us share his caution, or even think his principle too broad. For, at this distance of three and a half centuries, we see some of his examples rather as he sees them, as gross crimes against humanity, and some entirely differently, as the effect of local custom rather than as deeply rooted in core principles of morality. Thus, cannibalism, systematic murder of the elderly, and piracy (a type of terrorism) still seem very bad, and might possibly be occasions for humanitarian intervention. Incest seems highly plural and variable, and we tend to think that it is within the prerogatives of communities to define what is lawful and lawless in that sphere. (The sexual abuse of children, not mentioned by Grotius, seems the thing that ought to arouse really serious international ire, because it is a type of nonconsensual violence.) As for intercourse of male with male, there are, of course, people who do believe that this is a violation of the law of nature, though most people today do not. Nonetheless, even those people who basically agree with Grotius do not think widespread toleration of same-sex relations in a nation is an occasion for military intervention! Not surprisingly, sympathetic modern discussions of Grotius’s chapter do not mention this example.

If Grotius’s list is overinclusive in these obvious ways, it also seems oddly underinclusive. Even though the examples are only examples, not an exhaustive account, they oddly fail to include the most obvious cases, perhaps because Grotius is determined to cling to classical mythology in order to avoid contemporary controversy. Genocide is nowhere mentioned; the widespread rape of women, mentioned as an occasion for humanitarian intervention by Alberico Gentili in his parallel discussion, is not mentioned. And of course slavery is not mentioned because Grotius thinks that slavery does not violate the law of nature. Religious persecution is the only one of the major concerns of today’s international community that Grotius does mention as an occasion for intervention, somewhat later in the same chapter (II.20.49), but even there he permits nations to oppress internal religious minorities.²⁹ On the whole, then, the examples do not greatly illuminate the general thesis; indeed, by their very oddness they cast doubt on its legitimacy, by showing how very hard it is, even when one is trying one’s best, to distinguish permanent moral principles from local customs.

Nonetheless, by now international reflection on these issues has arrived at a short list that commands a wide and long-lasting consensus. The international consensus focuses on the core principles of the moral law, violence and aggression: thus consensual acts such as sexual “offenses” are nowhere considered. Genocide, slavery, and the rape of women are at the core of the consensus, where the use of military force is concerned—though international human rights norms include a far longer list of basic entitlements as a persuasive matter. It would appear that Grotius’s general principles survive the skepticism induced by his odd list.

Grotius’s conclusion, then, is that moral respect for national sovereignty, combined with knowledge of both the greediness and the fallibility of human judgment, should make us very reluctant to intervene forcibly in the affairs of another nation. Yet in some grave and extreme instances it is both permissible and praiseworthy to come to the defense of the oppressed. The core of such cases is given by the basic principles of the moral law: the worst cases will be those that violate human dignity in some extreme and excessive way, typically through the use of violence and coercion. We may add that the reasons against intervention are weakened to the extent that the oppressed lack political rights, and to the extent that the regime generally lacks accountability. Finally, we may add that where there is no legitimate regime in place (as in some instances of civil chaos), the restrictions would also be to that extent weakened. Despite the obvious defects of Grotius’s discussion, its complexity and subtlety give it continued value, as a guide to this profoundly complicated issue.

VI. Duties of Material Aid?

From its inception, the cosmopolitan tradition has had difficulty with duties of material aid. Grotius’s defense of national sovereignty might seem to compound these difficulties, suggesting that the nation is the person’s proper home, and that any meaningful material redistribution ought to be carried out there. But in fact Grotius’s argument provides at least a starting point for reflection about material aid and redistribution in a world containing both nation-states and individuals with moral rights. He supplies the tradition with two key notions: common goods, and claims of need.

Grotius’s early writings on the seas already announce the principle that certain “common goods” of human life are the common property of all peoples and cannot be possessed by one nation as property.³⁰ Sea and air are the most obvious such goods, and Grotius argues vigorously for the common right of all the world’s peoples to use the seas. His position on disputed matters (how to view coastal waters, channels, and so forth) shifts over time, and is shaped by the political position he played in Dutch trade negotiations. But it remains a strong defense of free access: in general neither sea nor air can be converted into private property (II.2.3). Thus even in BP, where he is far more guarded about coastal waters and channels, he nonetheless defends a right of passage over rivers and even lands by the route that is nearest and most convenient, and argues that the voyagers and the merchandise they transport cannot justly be taxed unless the nation through which they pass incurs expense in protecting them (II.2.11).

But in BP Grotius advances a much broader principle of access to material goods, based on the idea of basic needs. In time of necessity, he argues, “natural equity” requires that you first try to meet your need from your own property. But if that proves impossible, you are permitted to use the property of others (II.2.6). Thus, it is forbidden to destroy surplus food, and anyone who needs it may use it; water may similarly be used in time of need. This same right seems to him to yield a right to possess and cultivate unoccupied land (II.2.4). Even within a territory, foreigners are entitled to cultivate and take possession of uncultivated land (II.2.17). Moreover, the right to the necessities of life includes, he argues, a right to “acts required for human life,” including the provision of “food, clothing, and medicines” (II.2.18). Grotius argues that there are certain “acts indispensable for the obtaining of the things without which life cannot be comfortably lived.” He argues that here we do not need to show the same degree of necessity that we need to show in order to justify taking someone else’s property, for here we are dealing not with a taking, but with a matter of right: even if the owner doesn’t consent, that does not undermine the claim of the needy, for, given that it belongs to the needy by right, it does not belong to the owner in any case. To hinder people from getting such necessities of life is a most direct violation of the moral law. Implicit in this right is another: to buy the necessities of life at a fair price. “[T]hus in times of extreme scarcity the sale of grain is forbidden” (II.2.19).

The details of what Grotius would permit remain in some respects obscure. For example, he says that people should not be forced to sell their own belongings to others (II.2.20). So the reach of his humanitarian principle is somewhat unclear, although it would appear that in the case of extreme need his account of ownership holds that the poor person actually owns the property by right, and the holder does not. Nor is it at all clear what mechanisms of redistribution he envisages, either within nations or between nations. In any case, we can see that his principle mandates as morally required a good deal of redistribution both within nations and from richer to poorer nations. Particularly interesting is the analysis of ownership, which does not concede that current holdings settle the question, in circumstances of extreme need. Indeed, ownership is relative, not only to the welfare situation of my own fellow citizens, but also to the welfare of all world citizens. What person P owns in country A depends on facts about countries B and C: if there are hungry and suffering people there, then A does not own a certain luxury amount of goods that A would otherwise own.

What Grotius appears to be after is a set of minimal welfare rights, and in a worldwide framework: all world citizens are entitled to what they need in order to live, including food, shelter, and health care; and those things are theirs by right, even if they must come from another country. Even if there is no mechanism suggested to make these rights effective, they are said to be morally justified. Thus nations that do not meet the claims of need of people in poorer nations are violating the moral law.

Grotius is also very concerned with the situation of people who are forced by need or political circumstances to leave their own country (as he himself was). Migrants, he argues, have a right of temporary sojourn in another land (II.2.15)—which includes a right to build a temporary dwelling on land owned by that other nation and its people. If they have been driven from their homeland they have a right of permanent asylum, provided they are willing to submit themselves to the legitimate government of that nation (II.2.16). Moreover, even in a time of extreme need it is not permitted to expel foreigners who have once been admitted to a country: a common misfortune must be endured in common (II.2.19). Moreover, the right to “such acts as human life requires” includes a right to seek marriages in foreign countries, because it is repugnant to humanity to require people to live a celibate life (II.2.21). (Thus, to use a modern example, guest workers could not be forbidden to marry and establish a family in the nation into which they have migrated.) And within a nation that has admitted people from other countries, one foreign group cannot be singled out for special discrimination. Thus, if foreigners of any type are given certain rights, all law-abiding foreigners must be given those same rights (II.2.22).

Thus, despite the salience of national boundaries in Grotius’s thinking, his picture of the world is highly porous, protecting a lot of the movement of peoples from nation to nation (as religious persecution frequently required), and protecting certain minimum welfare rights for all world citizens, even when the wherewithal to meet those needs must come from another nation’s store. Even if all of this is highly abstract and not well connected, in some cases, to real political principles, we can see that it represents a radical departure from the Ciceronian picture. People are not required to give up bare necessities of life, but they are required to give up (or rather, told that they in fact do not own) whatever is over and above that, if other people are below the threshold of basic need. The picture of an interdependent and interacting world that the Ciceronian doctrine already realizes for issues of aggression is now realized in the area of material need as well, in a way that, if tantalizing, seems highly promising for contemporary thought about what a decent international society would require.

Sadly, Grotius never connects his doctrines concerning war and humanitarian intervention to his doctrine of material aid and ownership. Suppose there is widespread misery and acute poverty in country C, resulting from gross inequalities in material entitlements or a greedy tyranny. Is the failure to set this right a crime that excessively violates the law of nature, so that humanitarian intervention would be justified? It might appear so, for according to Grotius’s analysis the rich do not actually own the over-threshold goods that they are holding onto, so his understanding of the situation is that the poor are dying because the rich are holding onto goods that rightfully belong to the poor. Perhaps these violations of the law of nature are not “excessive,” but they do look like the sort of thing that undermines the very nature of human dignity and human fellowship.

Again, suppose that there is widespread misery and poverty throughout country C, because wealthy nations A and B are holding on to their surplus. They are violating the law of nature, and, according to Grotius, a portion of their holdings actually rightfully belongs to the suffering citizens in country C. Does that mean that an invasion of A and B by C would be a just war, provoked by wrongful aggression of A and B against C? If we combine Cicero’s account of just war (in which property crime is sufficient aggression to justify a violent response) with Grotius’s very un-Ciceronian doctrine of ownership, it would appear that this war is indeed a just war. Obviously enough, in cases of this sort C will rarely be in a position to invade A and B, because the very factors that make it poor also, very likely, make it militarily weak. But it is interesting to reflect about the fact that aggression by C may be morally justified, whether politically feasible or not.

Clearly, this is a point at which national sovereignty should affect the analysis. It seems perfectly justified for a sovereign nation to redistribute wealth through a system of coercive taxation. For another nation to use coercive strategies to effect a needed redistribution, even where need strongly recommends it, would mean global chaos and disorder. Moreover, there seems to be a moral wrong involved, of the sort that is involved in humanitarian intervention in all but the most egregious cases. As in that case, so here, two moral claims appear to conflict. Perhaps it is legitimate for the community of nations to exert pressure on the recalcitrant rich nation, through diplomatic pressures of various types. But to say that war is justified to effect economic redistribution seems extremely implausible, and I do not think the implausibility derives entirely from the sway of current holdings over our imaginations. Nor does it appear to derive only from prudential considerations of stability and security. The right to allocate resources seems to lie at the core of the very idea of national sovereignty, and if that idea has moral weight, it ought to limit coercive redistributions of wealth from one nation to another, absent, at least, any consent-based system at the supranational level. Grotius makes the tension clear, but in the end his analysis seems to agree with mine: we should, albeit uneasily, respect national sovereignty, but try to work through persuasion toward a consensus supporting need-based redistribution.

Even when we take its clear limits into account, however, Grotius’s new moral analysis has significant implications for international debate and policy.³¹ It is unfortunate that Grotius never pursues the radical implications of his ideas. But it is always open to us to do so, and the failure of international law to take up this strand in Grotius’s thinking, while it has been so heavily influenced by Grotius in other respects, shows an unfortunate quietism in the face of current holdings that Grotius himself does not countenance. Scholars have often criticized BP as a grab-bag for its inclusion of such allegedly irrelevant topics as property rights. Grotius is ahead of them, for he sees that lasting peace in the world requires a radical rethinking of just that issue.

VII. The Idea of International Society

In the twentieth century, wrote international law scholar Hedley Bull near its close, we saw a retreat from the confident assertion that “the members of international society were states and nations, towards the ambiguity and imprecision on this point that characterised the age of Grotius.”³² We are now in a position to assess Grotius’s accomplishment, and the picture of international society with which it leaves us. According to Grotius, then, the primary subject of morality, and of the moral part of political thinking, is the individual human being, seen as having dignity. That dignity gives the person a claim both to freedom from aggression and to the basic necessities of life. The person is also, however, social: the dignity of the person is to be understood as the dignity of a being who lives in complex forms of cooperation with others. So part of protecting human dignity is protecting the choices people make to band together and organize their lives in political communities.

This leads to a picture in which sovereign nations have a large place, but in which they share their power with international law, and with the more complex and indeterminate linking of all human beings in what is called “international society,” the society of all human beings living under moral law. Because the source of sovereignty is the dignity of the individual, that dignity is never completely ceded to sovereign nations, who must consequently share their powers, in complicated ways and in a complicated system of claims and restrictions, with the urgent claims of individuals both inside and outside of their borders. These claims include traditional human rights claims involving aggression and violence; they also include claims to things and acts that are necessary for life. Moreover, other associations, less amply sketched by Grotius, but occasionally mentioned (conferences, trade groups) will also play a role, and frequently their operations will cross national boundary lines.

Surrounding and permeating this entire system is the moral law. But the moral law does not exert its authority directly, as in the Moral Rights position. It too has to cede some of its powers—to sovereign nations, which derive their powers from it, but also limit it in their turn. The moral law informs international law, but also goes beyond it—not only because actual states are unlikely to accept all of its stringent demands, but also because some of these demands are not the sort of thing that rightly ought to be made into positive law. The line between the coercively enforceable and the morally urgent but unenforceable is indefinite, both in Grotius’s time and in ours, and it is continually shifting, as international society finds ways to make moral norms into positive law. The moral law informs the institutions of international civil society as well, since they may play an important role both in shaping international law itself and in bringing about a greater awareness of moral requirements that do not have the force of law. Finally, the moral law both limits and protects individuals, defining their entitlements and their duties.

The Grotian conception of international society is clearly superior, both descriptively and normatively, to the conception that Bull rightly describes as dominant for so long in the study of international relations: the conception of a world consisting of atomic nation-states whose relations among themselves are those of self-interest and security only. At this point in history, we can see that international relations is suffused with moral judgments of many kinds, and that nations do not limit their dealings with one another to national security interests. Nor was that ever a normatively satisfactory position, since, as Grotius plausibly argues, the very aspects of human life that give national sovereignty its deep importance also limit it, in favor of a broader multi-layered consideration of international law, international morality, and individual human rights.

What are the viable alternatives to the complex Grotian picture of the world?³³ One is the idea of a world government. As Bull notes, such a government might emerge from struggle between powers, but then it would very likely be a tyranny of an obviously objectionable sort. Again, it might emerge by way of a social contract of sorts between member states, in light of ecological or other disasters: Kant and others conceive of such an eventuality. Finally, it might emerge gradually, through a broadening of the powers of a federation such as the United Nations.

In the latter two cases, there is no immediate reason to think that world government need be tyranny: its internal structure might be highly protective of human rights. But there is clearly danger in its very ubiquity and dominance: for what can check it if it begins to go awry? Even apart from this danger, there is moral difficulty in the idea. First of all, could any government this inclusive possibly be sufficiently accountable to the governed, and expressive of their wishes? It’s hard enough preserving accountability in the nation-state. The global extension of power creates, obviously, huge difficulties for accountability, including the very grave question of the language(s) of the political process and, more generally, the protection of access to it. Certainly the mention of the United Nations ought to give us pause, for that institution is woefully deficient in accountability to the nations it allegedly represents. And the current crisis of the European Union indicates that people will not be satisfied by a central government perceived as distant and elite.

The mention of language raises an even deeper moral issue: for the very effacing of plurality in favor of singleness seems to violate an aspect of human sociability that Grotius rightly prizes. Even if we imagine that the world government is highly protective of the rights and liberties of religious, linguistic, and ethnic minorities, still, the very fact of its uniform structure excludes alternative structures, languages, and constitutional choices that may all be morally decent. There is not one unique right way to construct a state; instead, the moral law suggests a zone of moral permissibility, with many possible realizations. Removing this variety is itself a harm to human beings.³⁴

A second alternative picture of global society is Kant’s, further developed in the twentieth century by John Rawls.³⁵ Sovereign nations are the members of the world order, and they connect only in a compact regarding their (peaceful) international relations. This picture fails to grant that issues such as migration, asylum, the protection of the environment, and material aid rightly ground duties linking one nation to another. I have tried to show that Grotius has good reasons for questioning that approach.

There is another alternative to the world state, and that is what Bull dubs a “new medievalism.”³⁶ In the medieval world, there were rulers, but no truly sovereign nations: each ruler “had to share authority with vassals beneath, and with the Pope and (in Germany and Italy) the Holy Roman Emperor above.”³⁷ So too, we might imagine a kind of order, though not a theocratic order, uniting the world in the absence of a centralized world government:

We might imagine, for example, that the government of the United Kingdom had to share its authority on the one hand with authorities in Scotland, Wales, Wessex and elsewhere, and on the other hand with a European authority in Brussels and world authorities in New York and Geneva, to such an extent that the notion of its supremacy over the territory and people of the United Kingdom had no force.³⁸

This paragraph, written in 1977, seems prescient in one way: for indeed, as the “new medievalists” project, there is today a Scottish Parliament, and there is a European authority in Brussels, and with both of these the government of the United Kingdom has been sharing its authority to a certain degree—until the Brexit vote of 2016 severed the connection to Brussels in a way as yet to be determined. Nonetheless, the situation envisaged by the new medievalists has not come about: for citizenship, political participation, and economic entitlements are still in a very significant sense grounded in the nation, and it certainly is not (yet) true that the “notion of its supremacy over the territory and people … ha[s] no force.” Economic globalization is another factor, not foreseen by Bull, that undermines national sovereignty. And yet, it seems that we are likely to live for some time in a world in which nation-states play something like the role Grotius envisaged, giving up their power to these other entities only at the margins.

What about normative issues, however? Would the “new medieval” world be in significant ways a better world to live in? It seems highly dubious. Nation-states are on the whole good protectors of the basic rights of their citizens, through constitution-making or its analogue, and a combination of legislative and judicial oversight. It seems unlikely that a diffuse system that leaches away powers from the nations will do better at protecting the rights of minorities, women, and the poor. Within each subgroup that sets itself up against the nation, there are likely to be differences of power, and we can already see many instances (for example, systems of religiously based personal law) in which minorities do significantly worse under the “local” authority than they would were they directly under the power of the nation. Supranational and transnational groups of many kinds may indeed play a valuable role in pushing nations toward greater recognition of human rights; and yet, if there is not to be a world state, with all its threats, it seems likely that such groups ought to remain plural, decentralized, and, in the main, focused on persuasion rather than coercion. Such entities, once again, are highly unlikely to be fully accountable to people; and, once again, they are all too likely to enforce a uniformity that the moral law does not require, precluding other permissible forms of human organization. Supranational coercion is appropriate for very grave offenses against human rights. But the current skepticism about any form of international coercion, however mild, suggests that we should ourselves remain mindful of the need for accountability, and for respect for permissible human variety.

To the extent to which the “new medievalism” is indeed emerging in our world, it is taking a form quite unlike that envisaged in the 1970s, and one that cries out urgently for Grotius’s strong defense of national sovereignty. For it has taken the form of economic globalization, with multinational corporations leaching away sovereignty from the poorer nations as they pursue policies that are not exactly motivated by the moral law. This form of medievalism is a reality; but it shows the moral danger of the idea, since the global market is amoral and unaccountable. Nations, with their accountability to the lives of real human beings, continue to have the moral weight that Grotius ascribed to them, and the defense of their sovereignty seems even more important, perhaps, than it did in his time. Their connections are thicker and more complicated than those envisaged by Kant and Rawls: they go beyond questions of international relations. But the nation is still the primary locus of human self-expression and human autonomy.

I shall return to these questions in Chapter 7. But it seems fitting to end this chapter with a Stoic passage near the ending of BP, addressed to rulers, but suited as well to democratic subjects:

Rightly the same Cicero says that “it is an impious act to destroy the good faith which holds life together.” To use Seneca’s phrase, it is “the most exalted good of the human heart.” And this good faith the supreme rulers of men ought so much the more earnestly than others to maintain as they violate it with greater impunity; if good faith shall be done away with, they will be like wild beasts, whose violence all men fear … Violence is characteristic of wild beasts, and violence is most manifest in war; wherefore the more diligently effort should be put forth that it be tempered with humanity, lest by imitating wild beasts too much we forget to be human. (III.25.1, 2)

FOUR

Grotius