The idea that Hugo Grotius was an apologist for tyranny and had erected “injustice into a system” was advanced by Rousseau and Montesquieu, among other eighteenth century writers. "His constant manner of reasoning," complained Rousseau, "is to establish right by fact. A more satisfactory mode might be employed, but none more favorable to tyrants." The theme continues to find expression in contemporary histories of political thought, as in the exposition of Montesquieu given by Mark Hulliung, or Richard Tuck’s several explorations of Grotian doctrines, emphasizing the license that Grotius gave to offensive war. Here we want to take notice of the contrary view of Hersch Lauterpacht, formerly Whewell Professor of International Law at the University of Cambridge, in his once renowned but now forgotten essay on “The Grotian Tradition in International Law.” The essay was published in 1946 and was written in the immediate aftermath of World War II and the establishment of the United Nations. It is an essay of rare power and erudition, certainly one of the classics in the history of international thought, and one of the best critiques of realism extant. Lauterpacht himself regarded the paper, a tiny portion of his vast output, as "probably the most important he ever wrote." There is a longstanding argument over how much of the "Grotian tradition" reflects Grotius, and how much Lauterpacht, but little argument among scholars that the paper is a classic. (Article length: 6700 words)
Grotius himself was a prodigy, as famous as Erasmus, whose intellect traversed so wide a domain that he himself is reported to have said, on the approach of his death (by shipwreck, in 1645),“By undertaking many things I have accomplished little.” “The mysteries of the doctrines of Atonement and Transubstantiation,” says Lauterpacht, “were more real to him than the work on which his fame ultimately rested.” His dominant preoccupation became biblical exegesis and criticism, carried out for the vital contemporary purpose of reconciling warring Protestants and Catholics.
Lauterpacht details the criticisms assembled against Grotius, and concedes that many have merit. Of these the most damning is the lack of clarity of his overall view. With some exasperation, Lauterpacht recounts the difficulties:
The fact seems to be that on most subjects which he discusses in his treatise it is impossible to say what is Grotius’s view of the legal position. He will tell us, often with regard to the same question, what is the law of nature, the law of nations, divine law, Mosaic law, the law of the Gospel, Roman law, the law of charity, the obligations of honour, or considerations of utility. But we often look in vain for a statement as to what is the law governing the matter. . . .With regard to the crucial aspect of his work, namely, the law of war, it is often wellnigh impossible to elicit what is the law on the subject. . . . The treatise abounds in laborious and elaborate distinctions between diverse kinds of justice and various categories of law, but it is not always clear what object these distinctions are intended to serve. . . .[O]n the whole the various distinctions are unhelpful for the purpose of discovering what is the legal rule on the subject. There is no hierarchy of legal norms to assist the seeker after the correct rule of law. There is often little to guide us as to whether in case of conflict the law of nature (in its various and contradictory meanings) is to prevail over the law of nations or conversely.
Lauterpacht also finds fault with Grotius’s presentation of the laws of war, which was, “on the face of it, vitiated by the abandonment of the main object which the author set himself out to achieve.” Grotius observed in his Prolegomena that throughout the Christian world he had “observed a lack of restraint in relation to war, such as even barbarous races should be ashamed of,” and identified the humanization of war as the first among “many and weighty reasons for undertaking to write upon this subject.” And yet his concessions to existing practice, barbarous as it was, went far to elevating such crudities into the law of nations. “The law of nations,” as Lauterpacht summarizes some of these concessions,
gives the right to kill or injure all those who are in the territory of the enemy. The same right is given with regard to the subjects of the enemy wherever they may be found. Captives taken in war may be killed. So can those who surrender but whose surrender is not accepted. Water may be polluted, though not by poison. Both by the law of nations and by the law of nature it is permissible to use assassins. In general, by the law of nations anything is permissible as against an enemy.
Lauterpacht notes that Gustavus Adolphus, King of Sweden, carried with him Grotius’s treatise as he burned the countryside through which his armies passed in the Thirty Years War, for the purpose of depriving his enemies of sustenance. It is not clear, Lauterpacht concludes with some degree of angst, that Grotius’s interventions in the controversies over jus in bello helped produce the mitigation in the severities of war that occurred in the century after its publication. (This judgment is in sharp contrast with the view of Henry Wheaton, writing almost exactly one hundred years before Lauterpacht and emphasizing Grotius's wholly benign influence.)
Despite various flaws of “method and substance,” Grotius’s work achieved extraordinary fame and won a reverent respect from the eminent authorities on international law in the following century, including Pufendorf, Bynkershoeik, Wolff, and Vattel—“even when, as often happens, they disagree with him.” Lauterpacht suggests a variety of reasons for this—“the timeliness of the treatise, its comprehensiveness as an exposition of international law, its wide jurisprudential background, and the already consideration reputation of its author.” Of these factors, the timeliness of the treatise deserves special note:
At the time that De Jure Belli ac Pacis was published the historic process of the disintegration of European political society as hitherto known and the rise of the territorial sovereign state were being consummated. The Thirty Years War, which, to all appearances, was a war of religion, actually began and continued as a war of secular claims and ambitions of dynasties and nations. The rivalry between France and Spain had been a problem of European politics for three centuries. It had been kept in check by the overriding unity of religion. The Thirty Years War, when Catholic France allied herself with the Protestant cause in opposition to the dynastic ambitions of the Hapsburgs and when the Pope, for similar reasons, stood aloof at a time of deadly peril for the Catholic party, showed clearly the implications of the change. In a different sphere the demise of the feudal system gave a new and higher significance of the territorial state. The need for a system of law governing the relations of the independent states to replace the legal and spiritual unity of Christendom had thus become urgently obvious.
Ultimately, however, the reason for Grotius’s fame is “that the principal and characteristic features of De Jure Belli ac Pacis are identical with the fundamental and persistent problems of international law and that in nearly all of them the teaching of Grotius has become identified with the progression of international law to a true system of law both in its legal and in its ethical content.” Lauterpacht enumerates eleven ideas as fundamental to the Grotian tradition:
the subjection of the totality of international relations to the rule of law; the acceptance of the law of nature as an independent source of international law; the affirmation of the social nature of man as the basis of the law of nature; the recognition of the essential identity of states and individuals; the rejection of ‘reason of State’; the distinction between just and unjust war; the doctrine of qualified neutrality; the binding force of promises; the fundamental rights and freedoms of the individual; the idea of peace; and the tradition of idealism and progress.
The elaboration of these fundamental principles in the Grotian tradition takes up some thirty pages in Lauterpacht’s 25,000 word essay; I have tried to select those passages which give the gist of his teaching.
1. The Subjection of the Totality of International Relations to the Rule of Law. Modern international law recognized for a long time the existence of gaps which obliterated altogether the border-line between law and lawlessness in international relations. Of these gaps the admissibility of war as an absolute right of states, requiring no other legal justification, is the outstanding example. In laying down the distinction between just and unjust war Grotius rejected the claim to any such right. . . .Although he did not achieve the impressive solemnity of Suarez in the affirmation of the unity of mankind and of the existence of a community of nations, he put the recognition of the interdependence of states and of their subjection to law in the forefront of the treatise.
2. The Acceptance of the Law of Nature as an Independent Source of International Law. The significance of the law of nature in the treatise is that it is the ever-present source for supplementing the voluntary law of nations, for judging its adequacy in the light of ethics and reason, and for making the reader aware of the fact that the will of states cannot be the exclusive or even, in the last resort, the decisive source of the law of nations. . . .In the absence of the overriding authority of the judicial and legislative organs of the state there must assert itself—unless anarchy or stagnation are to ensue—the persuasive but potent authority of reason and principle derived from the fact of the necessary coexistence of a plurality of states. This explains the pertinacity, in the international sphere, of the idea of natural law as a legal source. . . . The law of nature has been rightly exposed to the charge of vagueness and arbitrariness. But the uncertainty of the ‘higher law’ is preferable to the arbitrariness and insolence of naked force. These considerations explain the significance of this aspect of the Grotian tradition in the history of the law of nations. He secularized the law of nature. He gave it added authority by making it an integral part of the exposition of a system of law which became essential to civilized life.
3. The Affirmation of the Social Nature of Man as the Basis of the Law of Nature. For Machiavelli and Hobbes man is essentially selfish, anti-social, and unable to learn from experience; homo homini lupus [man is a wolf to man] is the fundamental truth; human nature does not change; pessimism as to the potentialities of its improvement is of the essence of sanity; the basis of political obligation is interest pure and simple; the idea of a sense of moral duty rising supreme over desire and passion is a figment of imagination fatal alike to action and to survival. . . .On that line of reasoning there is no salvation for humanity but irrevocable subjection to an order of effective force which, while indifferent to the dignity of man, yet contrives to prevent his life from being 'solitary, poor, nasty, brutish, and short'. The approach of Grotius and—to mention a writer as distinguished and as influential—Locke is diametrically different.
One of the salient characteristics of De Jure Belli ac Pacis is not only the frequency of the reliance on and appeal to the law of love, the law of charity, of Christian duty, of honour, and of goodness, and to the injunctions of divine law and the Gospel: the element of morality and the appeal to morality are, without interfering decisively with the legal character of the exposition, a constant theme of the treatise. An equally persistent feature is Grotius's faith in the rational constitution of man and his capacity to see reason and to learn from experience. This aspect of De Jure Belli ac Pacis goes a long way towards explaining the force of the Grotian tradition in the international sphere. For there, more than anywhere else, the implications of the pessimistic estimate of human nature reveal themselves in all their paradoxical and depressing clarity. Writers and statesmen dwell lucidly and persuasively upon the incongruity and absurdity of the fact that modern civilized states live in a primitive state of nature in their mutual relations. They admit that the resulting situation is such as to threaten not only the rational growth of states but, in the age of scientific weapons, their very existence. They concede that only effective submission to a comprehensive rule of law and a corresponding curtailment of the sovereignty of states may avert these dangers. But after having thus diagnosed the evil and after having disclosed the remedy, they lay down the pessimistic proposition that governments and peoples are unlikely to agree to any such solution. [By contrast,] much of the appeal and potentialities of the Grotian tradition lies in the lesson which can be drawn from his conception of the social nature and constitution of man as a rational being in whom the element of moral obligation and foresight asserts itself triumphantly over unbridled selfishness and passion, both within the state and in the relations of states.
4. The Recognition of the Essential Identity of States and Individuals. This analogy of states and individuals has proved a beneficent weapon in the armoury of international progress. It is not the result of any anthropomorphic or organic conception of the state as being—biologically, as it were—assimilated to individuals, as being an individual person 'writ large'. The analogy is much more simple, more direct, and more convincing. The analogy—nay, the essential identity—of rules governing the conduct of states and of individuals is not asserted for the reason that states are like individuals; it is due to the fact that states are composed of individual human beings; it results from the fact that behind the mystical, impersonal, and therefore necessarily irresponsible personality of the metaphysical state there are the actual subjects of rights and duties, namely, individual human beings. This is the true meaning of the Grotian analogy of states and individuals. The individual is the ultimate unit of all law, international and municipal, in the double sense that the obligations of international law are ultimately addressed to him and that the development, the well-being, and the dignity of the individual human being are a matter of direct concern to international law.
5. The Rejection of ‘Reason of State’ [Although Grotius] does not mention Machiavelli by name, he takes up the issue of 'reason of State' at the very beginning of the treatise. After remarking upon the usefulness of a knowledge of the law 'which is concerned with the mutual relations among states or rulers of states',' he points to the special necessity of studying that branch of law. For, he says, there are 'in our day' persons who view it with contempt as having no reality; who consider that for a king or a state nothing is unjust which is expedient; and that the business of the state cannot be carried on without injustice. He sees an intimate connexion between the rejection of the ideas of 'reason of State' and the affirmation of the legal and moral unity of mankind. He insists that if no association of men can be maintained without law, 'surely also that association which binds together the human race, or binds many nations together, has need of law'. This means, he says, quoting Cicero with approval, that shameful acts ought not to be committed even for the sake of one's country. It means also that the hall-mark of wisdom for a ruler is to take account not only of the good of the nation committed to his care, but of the whole human race. 'The name of Minos became odious to future ages for no other reason than this, that he limited his fair dealing to the boundaries of his realm.' While denying that law is based on expediency alone, he was ready to meet the theorists of 'reason of State' on the ground of their own choosing, namely, that of advantage. He records the fact that according to many the standards of justice applicable in the relations of individuals within the state do not apply to a state or the ruler of a state. The reason usually given for that assertion of the double standard of justice is, he says, that law is indispensable to individuals who, taken singly, cannot protect themselves, while great states, which dispose of everything needed for adequate protection, are in no need of law. Grotius rejects this view. Such, in his opinion, is the impact of economic interdependence or of military security that there is no state so powerful that it can dispense with the help of others.
Grotius's rejection of the ideas of raison d'etat finds more direct expression in relation to concrete issues. It expresses itself in the denial of the right to resort to war unless in pursuance of a good legal cause; in the rigid limitation of the right of self-defence (including the right of war in order to ward off an anticipated attack); in the concession of the right—indeed, in the injunction of the duty—of passive resistance against orders and laws contrary to the law of nature and the law of God; in the concession to the subject of the right—and, again, in the injunction of the duty—to refrain from participation not only in unjust wars but also in wars the justice of which is doubtful; in his stressing of the sacredness of the principle pacta sunt servanda . . .
There is a symbolic significance in this rejection of raison d'etat by the founder of modern international law. For there is an inherent antagonism between international law, which, except when conceived as an empty and contradictory ‘law of co-ordination’, means restraint upon freedom of action, and the idea of reason of state, which means freedom from restraint. It would be mere speculation to attempt to assess the influence of Grotius on curbing the profane outlook which drew its inspiration from Machiavelli —just as it may be difficult to estimate the actual impact of The Prince upon the practices of international politics and diplomacy. It is immaterial that the succeeding four centuries witnessed the unprecedented ascendancy of the ideas of 'reason of State'. . . . . What is disquieting in the matter is the continued fascination, in one form or another, in the science of history and in the literature of international law, of the basic ideas of 'reason of State' and the apparent difficulty experienced by those who condemn it to cut themselves adrift from it wholly and unequivocally . . .
The great issue of 'reason of State' is still with us and, while it will continue to be an absorbing dilemma of historical science, it is one of the main problems of international law—perhaps the central problem if by law we understand restraint and if by 'reason of State' we mean rejection of any substantial restriction upon the freedom of action of sovereign states in matters which matter. The 'raison d'etat' may no longer present itself in the international sphere in the cruder forms of treacherous violence, of brazen perfidy, and of outright deceit—although recent history has shown that species of ratio status to be not altogether obsolete. Modern formulae such as that international law is possible only as a ‘law of co-ordination’ effected by agreement of sovereign States express ideas of distinct affinity with those of 'reason of State'. For there is probably more truth than exaggeration in the view that uncompromising insistence upon the unlimited rights of state sovereignty in contempt of the interests of other nations, of the interdependence of states, and of the public opinion of the world, is one of the manifestations of the spirit of ruthless egotism which has become associated with the idea of raison d'etat.' The claim of sovereign states—a claim fully admitted by existing law—to be entitled to deny to other members of the international legal community the benefit of judicial determination of disputed legal rights belongs, essentially, to the same category. So does the practice—reminiscent of the Machiavellian doctrine of the virtues of the pretence of virtue—of cloaking the refusal to limit the state's full freedom of action in the garb of pretentious phrases and purely nominal declarations implying some such submission. So does the assertion, which is an attempt at a rationalization of the existing practice, that the subjection of states to the rule of law in the international sphere is and ought properly to be limited to matters which are not 'political' and which do not affect their vital interests.
6. The Distinction Between Just and Unjust Wars. It is not the dagger or the poison of the hired assassin or the sharp practice of the realistic politician which expresses most truly, upon final analysis, the ideas of 'raison d'etat'. It is the infliction, without a shadow of a specific right and without a claim to any particular right, of the calamities and indignities of war and of the territorial mutilation and the very annihilation of statehood following upon defeat in war. Prior to the changes introduced by the Covenant of the League of Nations, the Pact of Paris of 1928, and the Charter of the United Nations, that central idea of 'reason of State' formed part of international law. States claimed—and had—the right to resort to war not only in order to defend their legal rights but in order to destroy the legal rights of other states. In the sphere of political theory Machiavelli put the position with his usual terseness: ‘That war is just which is necessary.’ And he added, by way of explanation: ‘The people will complain of a war made without reason.’ Bacon, who did more than anyone else to transplant the ideas of The Prince to English soil, and who praised Machiavelli for seeing 'things as they are', expressed similar views in holding that while a civil war is like the heat of a fever, a foreign war is like the heat of exercise, and helps to keep the body in health. To this set of ideas Hegel, Treitschke, and other nineteenth-century German theoreticians of 'reason of State' may have added the nebulous and arrogant pretentiousness of philosophical jargon; in fact they added to it little.
But although this particular—and most important—manifestation of `reason of State' became and for centuries continued to be part of international law, it was not an unchallenged doctrine. It was opposed by the parallel and powerful current of opinion that distinguished between wars which, in law, were just and those which were not. That current of opinion is represented by yet another aspect of the Grotian tradition, namely, his denial of the absolute right of war and his consistent differentiation between just and unjust wars. Grotius did not invent that distinction. It was part of the heritage of the Middle Ages; it was fully discussed and adopted by scholastic writers and other forerunners of Grotius. Saint Augustine elaborated in detail the notion of a just war and limited it to action taken for the punishment of wrong-doing and to restoration of property taken away. . . . In the elaboration of the causes of just war Grotius made no obvious advance upon the already elaborate treatment of the subject by his predecessors. The merit of his own contribution lies in the clarity and in the emphasis with which he treated the subject. For a war to be just there must exist a legal cause for it—a reason which would be recognized by a court of law as a cause of action. As he points out, war begins where judicial settlement ends. It follows that a war undertaken to enforce a claim which 'is not an obligation from the point of view of strict justice' is not a just war. He devotes an entire chapter to an enumeration, by way of example, of various kinds of unjust war. On the other hand, the causes of just wars are limited to defence against an injury either actual or immediately threatening, to recovery of what is legally due, and to inflicting punishment. He definitely excludes wars undertaken in order to weaken a neighbour who is a potential threat to the security of the state. He says, with regard to such a war, in a passage typical of the temper of the work in its challenging rejection of raison d'etat: 'That the possibility of being attacked confers the right to attack is abhorrent to every principle of equity. Human life exists under such conditions that complete security is never guaranteed to us. For protection against uncertain fears we must rely on Divine Providence, and on a wariness free from reproach, not on force.' He says in another part of the book: 'That defence may be just, it must be necessary; and it cannot be this, except there be clear evidence, not only of the power, but also of the animus of the party; and such evidence as amounts to moral certainty’. By way of example he discusses the case of the justice —which he denies—of a war undertaken against a neighbouring state on the ground that it engages in building a fortress or fortifications which might prove a source of danger. Against such apprehension, he says, the proper remedy is to build counter-fortifications, not to resort to arms.' The relevant section of Book II—the shortest paragraph in the treatise—consists of one sentence, significant and impressive in its brevity, referring to the causes of war: 'Advantage does not confer the same right as necessity.' He also denies that there is any question of a justifiable war of defence in the case of those who deserved the war waged against them. . . .
International law, in the three centuries which followed De Jure Belli ac Pacis, rejected the distinction between just and unjust wars. War became the supreme right of sovereign states and the very hall-mark of their sovereignty. To that extent international law was deprived of a reasonable claim to be regarded as law in the accepted sense of the word. The law on the subject has now undergone a fundamental change. War has ceased to be a supreme prerogative of states. The Grotian distinction between just and unjust war is once more part of positive international law. Factors more potent and more irresistibly compelling than the influence of any single writer have had a share in that achievement. Yet, among the imponderables which have worked in that direction, the Grotian tradition occupies a high place. . . .
7. The Doctrine of Qualified Neutrality. It is theoretically possible for international law to declare that some wars are illegal and criminal and yet to lay down that the neutral states not involved in the war must act with absolute detachment in relation both to the aggressor and to his victim. The legal consistency of such a system of international law would be questionable; its ethical impropriety would be obvious. In any case such a solution would not have been in keeping with the spirit of De Jure Belli ac Pacis. Grotius's view on the subject is expressed tersely in the brief chapter on neutrality entitled 'On those who are of neither side in war'. He says: 'It is the duty of those who keep out of war to do nothing whereby he who supports a wicked cause may be rendered more powerful, or whereby the movements of him who wages an unjust war may be hampered.' It will be noted that these duties do not include the positive obligation to assist actively the state waging a just war. But they clearly imply a right to do so.
. . . The doctrine of qualified neutrality was rejected in the nineteenth century —with perfect logical consistency—by the overwhelming majority of writers. If every war is, in law, just, then neutrality must be an attitude of absolute impartiality. Occasionally writers of authority expressed their disapproval of neutrality thus conceived as being morally intolerable. But that denunciation of neutrality was in fact a condemnation of a system of international law, fully in operation at that time, in which resort to war was an unlimited right of sovereign states.
With the drastic limitation of the right of war as adopted in the Covenant of the League of Nations and in the General Treaty for the Renunciation of War, the law restored the historic foundations of the doctrine of qualified neutrality as taught by Grotius. The Covenant of the League, in permitting neutrality and in obliging the Members to resort to sanctions and other measures of discrimination against the Covenant-breaking state, was, in this respect, based on the principle of qualified neutrality. When in 1940 and 1941 the United States committed itself to a determined departure from the customary and conventional rules of absolute neutrality as they obtained in the nineteenth century, it invoked, among others, the argument that with the general renunciation and condemnation of war as an instrument of national policy, the right, asserted by the founders of international law, to discriminate against the aggressor was fully restored. Grotius's teaching on the subject was adduced in support of the attitude thus adopted. . . .
8. The Binding Force of Promises. To Grotius the obligation to abide by pacts is not only the basis of municipal law and of civil society; it is of the essence of the social contract. Without it the social contract is meaningless. As such, the obligation to keep promises is the principal tenet of the law of nature. It is an obligation which binds the ruler in relation to the contract which he has entered into with his subjects; they derive a clear legal right under it. And this, he adds, 'holds even between God and man'. It is not surprising that to him the binding force of treaties is the basis of international law. They must be kept even in relation to pirates and tyrants, in peace or in war; they may be made, according to the Christian law and otherwise, with infidels, and faith must be kept even with them. He lays down the modern and, in the circumstances, unexceptional rule that promises made during war or for the purpose of terminating a war are valid even if extorted by fear. The reason for this seemingly repulsive qualification is that unless this rule were adopted most wars would be incapable of termination. . . . [A]t a period of European history when the authority of the pledged word of treaties had become a byword—a phenomenon which was destined to become a recurrent phase in international relations—he made it the very pivot of his teaching.
9. The Fundamental Rights and Freedoms of the Individual. There is one perplexing aspect of the work of Grotius which appears to be alien to the spirit of his teaching as outlined so far and which calls for careful examination, namely, his attitude to the question of the freedom of the individual in his relation to constituted authority. . . . Grotius justified slavery and claimed to have found support for it in the immutable canons of the law of nature. He rejected the idea of the sovereignty of the people. He denied the right of resistance to oppression by the ruler. He did not see why, if an individual can voluntarily sell himself into slavery, a whole people should not be able to do so collectively. He attributed an irrevocable legal effect not only to collective voluntary submission, but also to conquest. He completed this chain of reasoning by including in his examples of unjust wars a contest waged by an oppressed people in order to regain its liberty. . . . What is the explanation of these views, so foreign to the spirit of his teaching and to his personal condition? [The key explanation is that] this frowning upon rebellion and the favouring of authority were in accordance with what were considered to be the essential needs of the times. The horrors of civil war were foremost in the minds of political thinkers. There was not, in this respect, much difference between Hobbes and Bacon on the one side, and Hooker, Gentilis, and Bodin on the other. They discussed in detail the right of resistance; they all rejected it. So, perhaps with less justification, did Pufendorf. At a time of general uncertainty and of loosening of traditional ties of society, national and international, order was looked upon as the paramount dictate of reason. . . . Considerations of this order must have weighed heavily with one in whose work the desire for peace was the dominant motive and the ever-recurring theme. This particular feature of Grotius's outlook appears clearly from his unheroic advice given to defeated peoples to yield to fate rather than to engage in a suicidal fight for liberty, for, he says, reason prefers life to freedom. Strange as it may sound, his attitude towards slavery was to a large extent determined by humanitarian considerations. Enslavement of those captured in war was an alternative preferable to the unlimited power, including the right to kill, which, in his view, the customary law of nations and, probably, the law of nature gave to the captor. His treatment of the institution of slavery is permeated throughout by a spirit of charity and mercy.
What is more important than these explanations is the fact that behind the façade of the general disapproval of the right of resistance there lay qualifications so comprehensive as to render the major proposition almost theoretical. Thus, according to Grotius, there is a right of resistance in cases in which the ruler, by virtue of an original or subsequent contract, is responsible to a free people (as was the case in Sparta); against a king who has renounced his authority or has manifestly abandoned it; who attempts to alienate his kingdom (but only so far as is necessary to prevent the transfer); who openly shows himself the enemy of the whole people —an elastic and formidable exception; who attempts to usurp that part of the sovereign power which does not belong to him; and, finally, where the people have reserved the right of resistance in certain cases. These exceptions as laid down by Grotius were relied upon as an authority for the justification of the resistance to and deposition of James II. If Rousseau had concentrated on the reality of these exceptions rather than on the appearance of the general proposition he would have found less reason for vituperation. It is unlikely that one or more of these exceptions did not recall to the mind of the reader the various articles of the Dutch Act of Abjuration against Philip of Spain.
Finally, in this connexion we must bear in mind other indications of Grotius's true attitude. Thus it is significant that, notwithstanding his reluctance to sanction recourse to war, he considers as just resort to war to prevent the maltreatment by a state of its own subjects. In such cases, he says, if a ruler 'should inflict upon his subjects such treatment as no one is warranted in inflicting, the exercise of the right vested in human society is not precluded'. This is, on the face of it, a somewhat startling rule, for it may not be easy to see why he permits a foreign state to intervene, through war, on behalf of the oppressed while he denies to the persecuted themselves the right of resistance. Part of the answer is, perhaps, that he held such wars of intervention to be permitted only in extreme cases which coincide largely with those in which the king reveals himself as an enemy of his people and in which resistance is permitted.
However that may be, this is the first authoritative statement of the principle of humanitarian intervention—the principle that the exclusiveness of domestic jurisdiction stops where outrage upon humanity begins. The doctrine of humanitarian intervention has never become a fully acknowledged part of positive international law. But it has provided a signpost and a warning. It has been occasionally acted upon, and it was one of the factors which paved the way for the provisions of the Charter of the United Nations relating to fundamental human rights and freedoms. In that development the teaching of Grotius has some share. . . .
10. The Idea of Peace. The tenth—and not the least important—aspect of the Grotian tradition is his pacifism. He does not deny that war is a legal institution. On the contrary, he is at pains to show that war is not inconsistent with the law of nature and with many other kinds of law. There were good reasons—in addition to the recognition of a patent fact—for this initial legitimation of war. It would not be feasible to attempt to introduce a measure of legal regulation into a relation not recognized by law. A corresponding method suggested itself—and was adopted—with regard to the contents of the rules of warfare. Thus Grotius's treatment of the laws of war seems to be open to the charge that, after setting out to humanize rules of war, he gives the imprimatur of law to rules of pronounced inhumanity. His answer to any such criticism would probably have been that the proper course was not to deny the character of law to practices which apparently had secured a wide degree of acceptance, but to urge a mitigation of their rigours. . . .
In general, there breathes from the pages of De Jure Belli ac Pacis a disapproval, amounting to hatred, of war. There is nothing in that work reminiscent of the Baconian conception of war as a healthy exercise. Grotius is clear that where the question of legal right is doubtful, a state ought to refrain from war. He proposes various methods of settling disputes, including negotiation and arbitrations. He suggests that 'it would be advantageous, indeed in a degree necessary, to hold certain conferences of Christian powers, where those who have no interest at stake may settle the disputes of others, and where, in fact, steps may be taken to compel parties to accept peace on fair terms'. He devotes a whole chapter to 'warnings not to undertake war rashly, even for just causes'. Elsewhere, he distinguishes between justifiable wars, namely, those for which there is a true legal cause, and those in which the law is but a pretext. These latter he describes simply as wars of robbers. . . .
These intrusions of opportunism and realism did not decisively influence the character of De Jure Belli ac Pacis. But they are symbolic of the perennial problem with which the science of international law has been confronted almost from the outset. It has been exposed to the inducement to supply a rationalization of inferior and irrational practices; to confuse, in the name of realism, the function of chronicling events with that of a critical exposition of rules of conduct worthy of the name of law; to furnish a philosophy of the second best; and to represent the transient manifestations of immaturity and anarchy in international relations as resulting necessarily and permanently from the nature of states the mutual relations of which, it is said, may be regulated by voluntary co-operation but not by a rule of law imposed and enforced from above. Grotius did not succumb to that tendency. This fact explains much of the influence which he has wielded. For, in the history of political ideas and human progress, it will be found that the attraction of the short cuts of sound realism is matched—and surpassed—by the appeal to faith and to principle. . . .
Grotius did not create international law. Law is not made by writers. What Grotius did was to endow international law with unprecedented dignity and authority by making it part not only of a general system of jurisprudence but also of a universal moral code. To many, indeed, it may appear that De Jure Belli ac Pacis is more a system of ethics applied to states than a system of law. This would not inevitably imply a condemnation of the work. For it may be held that at that time—as, indeed, at any time—it was important that the relations of states should be conceived and taught as part of ethics as well as part of law. Grotius’s great merit is that he performed both tasks in one work.
For more on Lauterpacht, see the biography by his son, Elihu Lauterpacht, The Life of Hersch Lauterpacht, released as a paperback by Cambridge University Press in November 2012. Lauterpacht, as the book details, "was one of the most prolific and influential international lawyers of the first half of the twentieth century. Having come to England from Austria in the early 1920s, he first researched and taught at the London School of Economics before moving to Cambridge in 1937 to become Whewell Professor of International Law. He did valuable work to enhance relations with the United States during the Second World War, and was active after the war in the prosecution of William Joyce and the major Nazi war criminals. For ten years he was also involved in various significant items of professional work and in 1955 he was elected a judge of the International Court of Justice."