History of Law of War and Peace to WWII


by Allen Ferguson, JD, MFA


CHAPTER  ONE    Law and Ethics Concerning War and Peace Before 1945

The future is still uncertain, and no one, influenced by that
thought, should arouse enmities which are not future but certain.

— Thucydides (471-401 B.C.)


Whenever men proceed to vote on war
No one reflects that death hangs over him,
But each destruction for the other plans;
Had we, when casting votes, with our own eyes
The funerals beheld as we voted,
War-frenzied Greece would not have perished.

— Euripides (480 – 406 B.C.)


But I am wrongly judged if my love of peace and my
patience are mistaken for weakness or even cowardice.

— Adolph Hitler


That war is just which is necessary.

— Machiavelli

The international community has today a disorganized, sporadic, but not totally ineffective body of law and set of enforcement mechanisms concerning when war may and may not be commenced, and how it may and may not be fought. In order to understand laws affecting war and peace as they exist today, and to build a knowledge base that will enable us to democratically affect the future of the world in regard to war or peace, it is important to gain perspective on where these laws came from and how they developed.

A common impression is that laws relating to war and peace basically came into existence about sixty years ago, with post-World War II developments — the Nuremberg trials, the formation of the United Nations, the Geneva Conventions. Some would say that this body of law goes back another twenty-five years or so to the post-World War I era, the Treaty of Versailles and the formation of the League of Nations, or perhaps even a decade or two earlier, to the Hague Conventions of 1899 and 1907. Some historians believe, however, that the law of war and peace goes back more than five thousand years to about 3100 BC, when two Mesopotamian city-states concluded a peace treaty.1

As noted in the Introduction, laws affecting war and peace address two fundamental questions: (1) when is going to war justified (sometimes referred to by the Latin term “jus ad bellum”); and (2) what restraints are placed on the conduct of war (sometimes referred to as “jus in bello”.)



The Koran, presaging the United Nations Charter and the Final Judgment at Nuremberg by more than a millennium, forbids the initiation of war: “Fight in the way of God against those who fight against you, but begin not hostilities. Lo! God loveth not aggressors.”2 The Fourth Century B.C. Chinese philosopher and military strategist, Sun Tzu, in his still influential book The Art of War wrote that it is best to win a war without ever having to fight.3 At about the same time, half way around the world, the Greek historian Thucydides wrote, “Not those who ward off force with force break the peace, but those who are the first to make the attack.”4

Is the initiation of war ever justified? The Greek historian Plutarch (46 – 120 A.D.) did not think so. He wrote, “There is no war among men which does not originate in fault. One is kindled by an eager desire for pleasures, another by avarice, another by an overmastering passion for public office or supreme power.”5

To the early Christians, war and participation in war were contrary to the teachings of Jesus. Christians were forbidden to become soldiers, and soldiers who converted to Christianity were urged to quit the military. Arnobius wrote, “We have learned from [Christ’s] teachings . . . that it is better to suffer wrong than to be its cause.” In the Fourth Century A.D. the pacifism of the church changed, first with Emperor Constantine’s conversion to Christianity and then, in 380, with the warlike Emperor Theodosius I making Catholicism the state religion. St. Ambrose excommunicated Theodosius for ordering the massacre of 7000 Thessalonicans in retaliation for sedition, but allowed the emperor to re-enter the fold upon showing penance for his sins.

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The Just War Doctrine

The main theory through which Christianity, particularly Catholicism, attempted for many centuries to deal with the difficult issues of war and peace was the “just war doctrine.” The doctrine has many variations, and evolved over time. Saint Thomas Aquinas (1226-1274) identified three essential elements of a just war. First, the war must be undertaken under the authority of the sovereign. Second, the war must have a “just cause,” meaning it is undertaken as a result of some fault of the enemy. Third, the motivation for the war must involve rightful intention, that is, the advancement of good and the avoidance of evil. To these was added a requirement that the sovereign who initiates war must be certain of victory because otherwise the good that is the object of the war may not be achieved.

It is fair to say that the just war doctrine raises more questions than it answers. What type and degree of “fault” on the part of the enemy is required to justify attacking them? How can one tell whether a leader who decides to start a war intends to advance good and avoid evil? Does “good” include bringing Christianity to non-believers? (This seems to have been a key assumption behind the hundreds of years of bloodshed known as the Crusades.) Can “good” include expansion of empire? Or the spreading of democracy? What about the requirement that a head of state who contemplates going to war must be certain of victory in advance? Does this idea induce the leader to cause maximum death and devastation among the enemy for fear that otherwise he might not win?

It was the Spanish professor and cleric Francisco de Vitoria (1480-1546), who confronted the ambiguities of the just war doctrine and, through careful reasoning and application of theory to real world situations, transformed that confused doctrine into something coherent — something from which we have much to learn today.

Vitoria wrote and taught in Paris and Salamanca during the French Renaissance and the Spanish Inquisition. Spain was a religious absolute monarchy at the time, one in which tolerance was at a low ebb and religiously inspired state violence was prevalent, especially in relation to the newly “discovered” “barbarians” of the New World. Vitoria’s interest in law of war and peace sprang from his concern about the wars that Spain was waging at the time against the American Indians in the process of colonizing, converting, and enslaving them, something that we would refer to today as genocide.6

In his work on war and peace, Vitoria asked first whether it is permissible for Christians to engage in war at all. He concluded that it is permissible under some circumstances because if engaging in war were never permissible, “tyrants and thieves and robbers [would be] able to injure and oppress the good and the innocent without punishment whereas the innocent [would] not [be] allowed to teach the guilty a lesson in return.”7 Having concluded that it can be lawful to engage in war, Vitoria proceeded to examine different justifications offered for wars, analyzing each to determine whether it makes out a just cause for war.

Regarding the conquest, Vitoria addressed first one of the main justifications offered at the time for Spain’s invasion and occupation of the New World, the so-called “right of discovery,” based on the legal principle that deserted or unoccupied property belongs to the finder or occupier. Vitoria rejected the “right of discovery” justification for the conquest by pointing out that the Indians had possessed and occupied the land before the arrival of Europeans, and therefore the “right of discovery” did not justify the conquest “any more than it would if they had discovered us.”8 While this point may seem obvious to us today, we should recognize that lay behind Spain’s so-called “right of discovery” was the premise that the Indians were not “rational” beings and, therefore, had no legal right to own or control property.9 That is, the official line was that the Indians did not have rights; that they were not fully human. This theme of dehumanizing the enemy in order to justify attacking him or her continues to be played out today.

Vitoria also asked whether war can be justified on the basis that the people to be conquered do not share the religion of the attackers. Vitoria began with the just war principle that to be lawful, a war must have a just cause. What is a just cause for war, Vitoria asked. Culpable actions by those who are to be attacked, he answered. Therefore, if the Indians did no wrong, there can be no just cause for waging war against them. Did the Indians do wrong by failing to believe in the Christian religion? They did not, first because “those who have never heard about a thing are invincibly ignorant, and such ignorance cannot be a sin.”10 Second, even if Indians had Christianity presented to them, they could not be expected to adopt the Christian faith if the faith was not put forward to them in a persuasive way, such as with miracles, or at least “in a probable fashion, that is with provable and rational arguments and accompanied by manners both decent and observant of the law of nature, such as are themselves a great argument for the truth of the faith.”11 If this was not done, then the Indians did no wrong by refusing to accept the faith. How was the Christian religion presented to the Indians? “I have not heard,” Vitoria wrote, “of any miracles or signs, nor of any exemplary saintliness of life sufficient to convert [them]. On the contrary, I hear only of provocations, savage crimes, and multitudes of unholy acts. From this, it does not appear that the Christian religion has been preached to them in a sufficiently pious way to oblige their acquiescence . ..”12 Moreover, Vitoria reasoned, belief is a matter of will, and you cannot impose belief by fear because fear diminishes freedom of will. “War,” he said, “is no argument for the truth of the Christian faith. Hence the [Indians] cannot be moved by war to believe, but only to pretend that they believe and accept the Christian faith, and this is monstrous and sacrilegious.”13

Vitoria also asked whether war can be justified on the basis of expansion of empire.14 He answered that if war can be justified on that ground, then both belligerents could be in the right and, in that case, both would be innocent. But natural law forbids the killing of innocents, and therefore such a war is illegal.

Vitoria also asked whether war can be justified by the glory or convenience of the prince — a question we might read today as whether war can be justified by the political power or economic interests of a nation or a political faction within a nation. Vitoria answered that a king is distinguished from a tyrant by acting for the good of the commonwealth rather than his own profit and convenience. Free people, unlike slaves, do not live for the convenience of others, but for themselves. “For a prince to abuse his position by forcing his subjects into military service and by imposing taxes on them for the conduct of wars waged for his convenience rather than the public good is . . . to make his subjects slaves.”15

The sole legal justification for going to war, Vitoria wrote, is injury received. “We may not use the sword against those who have not harmed us [because] to kill the innocent is prohibited by natural law.”16 Vitoria cautioned, however, that not every injury is serious enough to justify going to war. Because punishment inflicted should be proportional to injury received, and all of the effects of war – slaughter, fire, devastation, etc. — are cruel and horrible, it is not lawful to go to war over relatively minor injuries.17 The proportionality principle to which Vitoria refers remains an important part of international law today. What is remarkable about Vitoria’s thinking about the proportionality principle is his recognition (which is even harder to dispute today than it was then) that war is inherently an extremely harsh punishment. Therefore, if the response must be proportional to the offense, war must be used only in response to the most serious and perilous kinds of international injury.18

Vitoria went beyond the question of when war is and is not justified to consider the process through which a decision about going to war should be taken.  The decision to go to war is so fraught with serious consequences for the entire country, Vitoria believed, that it should be weighed carefully and made by many people rather than few. It must be realized that the ruler is fallible and not capable of making such a momentous decision on his own. Therefore, he must listen carefully to those opposed to going to war, and consider their views. He also must listen to the views of the potential enemy and negotiate with them if they are willing to do so in good faith. People who are in a position to influence the decision, especially those in government, have a duty to study the issues carefully and to speak their minds, for every person who has power to prevent danger to his neighbor is obliged to do so. The person whose voice is silent but could have made a difference in the decision shares blame for whatever crimes ensue.

Hugo Grotius [1583-1645], a Dutch lawyer and statesman who lived a century after Vitoria is widely regarded as the father of modern international law, based largely on his seminal work, The Law of War and Peace, published in 1625. Grotius agreed with Vitoria that a distinction must be made between just and unjust wars, and disagreed in this regard with Machiavelli who had written “That war is just which is necessary.” Like Vitoria, Grotius believed that war based on religion is unjust.

Grotius rejected the theory that the sovereign power of the state is the supreme principle of international law and that states therefore have the absolute right to decide whether or not to go to war. Similarly, he rejected the theory that states have a right to take any action at all in self-defense. He saw an analogy between the law applicable to individuals and the law applicable to nations and took issue with the idea that a state can be so powerful that, unlike an individual, it does not need to rely on the constraints of law for its protection. There is no state so powerful, Grotius wrote, that it can dispense with the help of others.19

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The Imperial age and the Decline of Just War Considerations

Following Vitoria’s and Grotius’ time, in the 18th, 19th and early 20th Centuries, questions of the justice or injustice of going to war were subordinated to questions of power as state sovereignty became the dominant theme. Sovereignty was held to include an absolute right of each independent state to decide for itself the rightness or wrongness of going to war. As one influential teacher of international law put it in 1907, “Modern International Law does not attempt to decide upon the justice or injustice of war in general or any war in particular. It leaves such questions to International Morality . . .”20 In other words, despite the contrary teachings of such prominent thinkers as Vitoria and Grotius, making war became a more-or-less unchallenged legal right of every sovereign nation. The discarding of questions about the rightness or wrongness of going to war, along with the assertion of state sovereignty as the paramount principle of international law, removed impediments to European and North American imperialist expansion, domination and exploitation. The lack of any effective international organization or any mandatory means for enforcing treaty commitments made it relatively easy for kings, emperors, prime ministers and presidents to assert the authority of their individual states to go to war, and not to be held responsible for such decisions.

The Imperial Age principle of the absolute right of states to go to war as an important aspect of their sovereign powers continued, more-or-less unquestioned, until after the First World War, when it began to come under limited attack, a process that rapidly took on new and more powerful forms after the Second World War.

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The Right of Self-Defense

The question of the legality of going to war includes the question of the legality of using armed force in self-defense. On the inherent right of self-defense, the Roman philosopher Cicero (106-44 B.C.) wrote, “there is this law which is not written, but born with us; which we have not learned, . . . but . . . have sucked in . . . – the law that if our life has been placed in jeopardy by any snare, or violence, or weapons . . .every possible means of securing safety is morally right.” How does a nation know whether its “life” has been placed in jeopardy? What actions of an enemy justify military action in self-defense, and what types of military action do they justify?

The Nuremberg Tribunal in its Final Judgment recognized the customary right of states to use military force in self-defense, but did not agree with the Nazi defendants’ attempt to justify their invasion of countries such as Poland and Norway on that basis. Customary international law requires that in order for military action to be justified on the basis of self-defense, it must be both necessary to the protection of the state or its people and proportional to the attack against it.

Is military action in self-defense ever lawful if it is launched not in response to an armed attack, but before any armed attack has occurred? A famous answer to that question, still cited today, was given by United States Secretary of State Daniel Webster in a letter to British Foreign Secretary Fox in 1841. A state that wishes to justify military action taken in self-defense before it has been attacked, Webster wrote, must show “a necessity of self-defense, instant, overwhelming, leaving no choice of means, and no moment for deliberation” and that it “did noting unreasonable or excessive.”21

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Preemptive War

What about the claimed type of self-defense known as “preemptive war,” meaning a military attack to remove a perceived external threat which, however, is not “instant, overwhelming [and] leaving no choice of means and no moment for deliberation” — in other words, a perceived threat that is not imminent? We tend to think of this question as arising only very recently, perhaps with the United States’ 2002 invasion of Iraq. But the Roman orator Cicero addressed this issue twenty-one centuries ago: “To whom without the gravest danger to all men can it be granted that he shall have the right to kill a man by whom he says he fears that he himself later may be killed?”22 Even earlier, the Greek historian Xenophon (434-355 B.C.) observed, “I have known men who, becoming afraid of one another, in consequence of calumny or suspicion, and purposing to inflict injury before receiving injury, have done the most dreadful wrongs to those who had no such intention.”23 And Cato, a Roman statesman and soldier (234 – 149 B.C.) put the question this way: “Shall we be the first to do what we say they wished to do?”

Vitoria and Grotius also asked whether killing can be justified on the basis of anticipated future injuries from the people to be killed. “It is never right to commit evil,” Vitoria said, “even to avoid greater evils. . . . There are many other measures for preventing future harm from such people . . . It is not lawful to execute one of our fellow [citizens] for future sins, and therefore it cannot be lawful with foreign subjects either . . .”24 In other words, a preemptive strike, in Vitoria’s opinion, amounts to murdering someone you believe intends some day to murder you. According to Grotius, “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.”25

In line with the views of Cicero, Xenophon, Cato, Vitoria, Grotius and Webster, preemptive war, in the sense of military action intended to remove perceived, but non-imminent, threats has never been recognized as legitimate in international law. This seems a sensible result in view of such critically important historical facts as that Austria-Hungary attempted to justify its initiation of the World War I as a preemptive strike against Serbia.26

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The second big question that the international law of war and peace addresses is what methods and means of conducting warfare are permissible and what methods and means are not. Differently put, the question is what restraints are placed on the inherent violence, cruelty and destructiveness of war?

In ancient India, around the Fourth Century B.C. the Hindu Book of Mann set down prohibitions against fighting with concealed weapons or weapons with barbed, poisoned or flaming points, and forbid striking anyone who is disarmed, fleeing, a eunuch or naked, or one who places the palms of his hands together in a gesture of supplication.

Around the same time, Sun Tsu wrote that it was prohibited to injure an enemy previously wounded, or to strike the elderly.

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The Prohibition Against Attacking Civilians

Echoing ancient themes, Vitoria adhered strongly to the basic principle — which he believed to be dictated by natural law — that innocents or non-combatants may not be killed in war. Because “the foundation of the just war is the injury inflicted upon one by the enemy,” and “an innocent person has done you no harm,” it cannot be lawful to intentionally kill an innocent person in war.27 Moreover, he said, it is not legitimate to punish the innocent for the crimes of the evil-doers among them. Vitoria conceded, however, that it is occasionally necessary and permissible to kill innocent people in war if, for example, they are in a fort that must be attacked in order to pursue a just war, for otherwise, it would be impossible to pursue the war, and the just side would lose. However, “care must be taken to ensure that the evil effects of the war do not outweigh the possible benefits sought by waging it.”28 Therefore, if a fort or town that has many innocent people in it is not of critical importance to eventual victory, it is not right to attack it in order to defeat the combatants in it. “It is never lawful to kill innocent people, even accidentally and unintentionally, except when it advances a just war which cannot be won in any other way.”29

In medieval times, chivalric codes required that the lives of the population at large, as well as the lives of church clerics, be spared in battle, although these proscriptions were not always followed.30

Grotius believed that while a state may have a legal right, strictly speaking, to kill innocents who are in an enemy fort or aboard a pirate ship, “what accords with a strict interpretation of right is not always, or in all respects, permitted. Often, in fact, love for our neighbour prevents us from pressing our right to the utmost limit.” Therefore, “the decision in such matters must be left to a prudent judgment, but in such a way that when in doubt we should favour that course, as the more safe, which has regard for the interest of another rather than our own.”31

Like Vitoria, Grotius saw natural law is an independent source of international norms such as the prohibition against killing innocents. He believed that natural law includes goodness, morality and love as basic elements of human nature. He held that a wise ruler looks out not only for his own people, but for the entire human race. Even the fundamental principle of international law that nations must abide by their treaty agreements Grotius saw as grounded in natural law. Today, we can still ask what is the ultimate source of principles such as the prohibition against killing innocent people in war and the duty to obey treaties, and whether they aren’t based on fundamental beliefs about human nature or good and evil, rather than simply the products of custom and documents.

We see in the diverse ancient and renaissance writings cited above the historical roots of contemporary prohibitions against targeting civilians and punishing or taking revenge against an entire population.

However, after the Renaissance and before the 20th Century, humanitarian restraints on the conduct of war, like restraints on going to war in the first place, were loosened considerably. The general approach taken during the Imperial Age was that “[a]ll instruments and methods of destructions not expressly forbidden by International Law [were] allowed.”32 While the general prohibition against attacking non-combatants survived in theory, it was a watered down version of what Vitoria and Grotius had envisioned. The more “modern” rule of the Imperial Age was that “Non-combatants are exempt from personal injury knowingly and wantonly inflicted, provided that they submit to the lawful demands of the enemy and observe the regulations laid down by him.”33 In addition, the inhabitants of territory occupied by a foreign force in war were liable to perform any service for the enemy troops or government that was not distinctively military and pay contributions to the occupiers, and their personal property could be seized as spoils of war.34 However, the poisoning of food and water likely to be consumed by the enemy was prohibited.35

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Treatment of POW’s

The treatment of prisoners of war (or others detained in war), a subject of intense contemporary concern, also was a concern in ancient times. Seneca addressed it. “Is it . . . right,” he asked, “that orders should be given to a man with greater severity and harshness than to dumb animals?”36 Centuries earlier, Sun Tzu wrote that captives were to be treated well and cared for with magnanimity and sincerity, for otherwise they become useless to the captors. In the Fifth Century AD, St. Augustine wrote that prisoners must be treated with mercy. The principle of treating war prisoners humanely was one of the few humanitarian principles that survived in tact (at least theoretically) during the Imperial Age.37

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As we have seen, the political, economic and military expansionism of European and North American powers during the Imperial Age brought with it a decline in concern about the justice or injustice of going to war, a strengthening of the ideal of state sovereignty, and a decline in concern about mitigating the pain and suffering caused by war, particularly among civilians. At the same time, although the use of poison weapons was theoretically prohibited, there were few other restraints on the types of weapons that could be used.38

Developments in weapons technology, transportation and communications in the 19th Century made warfare even bloodier and more painful than it had been at earlier times, and these changes engendered early international attempts to impose controls on the types of weapons that could be used in war and the treatment of people involved in or affected by war. Because there were no international organizations capable of taking measures calculated to assure peace or mitigate the devastation of war, the only means available for concerned nations to take steps in that direction were (1) the negotiation of international declarations and treaties, and (2) unilateral actions.


The Geneva Convention of 1864 and the Exploding Bullet Declaration of 1868

One of the earliest widespread international efforts to mitigate the suffering of war was inspired by the Swiss Henri Dunant’s graphic descriptions of the bloodshed and suffering at the battle of Solferino during the Franco-Austrian War of 1859, in which the sick and wounded were miserably treated. In response, the government of Switzerland convoked an international conference in Geneva which, in 1864, produced a convention that assured neutral, protected status for persons and instrumentalities, including hospitals and ambulances, involved in caring for the sick and wounded in warfare and provided that they should display a flag or armband showing a red cross on a white field. This protection, of course, survives today. Foreshadowing future developments, the 1864 Geneva Convention also provided that “wounded or sick soldiers shall be . . . taken care of, to whatever nation they may belong.”

In 1868, four years after the Red Cross Convention, a group of nations convened at St. Petersburg, Russia and entered into a Declaration Renouncing the Use in Time of War of Explosive Projectiles. They were motivated by the conviction that “arms which uselessly aggravate the sufferings of disabled men, or render their death inevitable” are contrary to the “laws of humanity,” and bullets that explode or fulminate within the human body are such inhumane weapon. Accordingly, the signatory nations renounced the use of such exploding and inflammatory bullets. This was the first modern formal international agreement restricting the use of particular types of weapons in war.


The American Civil War

An early example of unilateral action designed, in part, to lessen the pain and suffering caused by war was the “Lieber Code” drafted by Columbia College Professor Francis Lieber and issued to U.S. Army commanders in 1863, during the American Civil War. The Lieber Code reiterated the power of each sovereign nation to go to war and to take such actions in prosecuting war as are required by “military necessity” but stated, “[m]ilitary necessity does not admit of cruelty—that is, the infliction of suffering for the sake of suffering or for revenge, nor of maiming or wounding except in fight, nor of torture to extort confessions. It does not admit of the use of poison in any way, nor of the wanton devastation of a district.” The Code also required humane treatment of prisoners of war and stated that “in general, military necessity does not include any act of hostility which makes the return to peace unnecessarily difficult.” The Lieber Code expressly forbade rape, murder, enslavement, and other crimes against citizens, and required U.S. soldiers to respect private property and “the persons of the inhabitants, especially those of women, and the sacredness of domestic relations.” It forbade pillage and private gain but stated, “[w]ar is not conducted by arms alone. It is lawful to starve the hostile belligerent, armed or unarmed, so that it leads to the speedier subjection of the enemy.” Moreover, the Code stated that in pursuing the ultimate goal of peace, “[t]he more vigorously wars are pursued, the better it is for humanity. Sharp wars are brief.”

General William Tecumseh Sherman should have had a copy of the Lieber Code with him when he carried out the devastation known as the “march to the sea” from Atlanta to Savannah in 1864, for the Code was issued the previous year to Union commanders for their use in the field. Perhaps Sherman read only the parts that allowed starvation of the enemy and urged “sharp” prosecution of war, and not the parts that forbade cruel treatment, rape, murder, pillage, destruction of private property and devastation of territory. This set of circumstances – norms regarding warfare that are not clear and lack an effective enforcement mechanism combined with powerful and sometimes irrational leaders with pre-determined military objectives—is a pattern repeated many times since 1864 – one that remains close to the core of the difficulties the world experiences in bringing about lasting peace.

The U.S. Civil War also brought about one of the first war crimes trials in history. The trial of Doctor Henry Wirz, a Confederate officer who was commander of the Andersonville, Georgia, prison camp in which thousands of Union soldiers died of starvation, exposure and disease, resulted in his conviction. Foreshadowing events that took place in a defeated Germany eighty years later, the court martial that tried Dr. Wirz rejected his defense of obeying superior orders, finding that he had obeyed such orders willingly, not under duress, and sentenced him to death by hanging. Also like the Nuremberg trials, the court marshal of Dr. Wirz was carried out by a military tribunal of the victors against the vanquished.

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The Hague Conferences of 1899 and 1907

It was Russian Tsar Nicholas II whose efforts led to one of the first international forums ever created to deal with a wide range of issues involved in warfare. In 1898, the Tsar called for all nations to join in a conference on limiting arms, restricting armed forces and arbitrating international disputes. The result was the Hague Conference of 1899, which representatives of 26 nations attended. That conference failed to achieve the goals of broadly limiting arms and meaningfully restricting armed forces, but it did result in a number of international agreements or treaties.

One of the treaties negotiated at the 1899 Hague Conference banned the use of bombs dropped from balloons. The prohibition against dropping bombs from balloons was renewed in the subsequent Hague Conference of 1907 and expanded to prohibit the dropping of bombs “by other new methods of a similar nature,” (presumably a reference to airplanes). The treaty stated that its ban on aerial bombardment would be in effect until the close of the third Hague peace conference, to be held eight years later, in 1915. The third peace conference was never held due to the outbreak of World War I, during which great advances were made in the use and destructiveness of aerial bombardment . The early 20th Century efforts to ban aerial bombardment did not take hold in practice, in later treaties, or at the Nuremberg trials. Pause to consider how vastly different the history of the world would have been in the century following 1907 had the early international ban of aerial bombing continued in effect and been followed. There would have been no bombing of London, no Pearl Harbor, no “strategic” bombing of Dresden, no firebombing of Tokyo, no Hiroshima, no Nagasaki, no bombing of Belgrade or Baghdad. Many millions of human beings, including millions of civilians, would not have fallen victim to this particularly effective method of committing homicide.

The Hague Convention of 1899 also established the first modern international body intended to adjudicate disputes between nations before they erupted into war, the “Permanent Arbitral Court.” Although the arbitral court had some successes in resolving disputes between states, possibly avoiding bloodshed that might otherwise have happened, its effectiveness was severely constrained by the fact that only those countries that submitted to its jurisdiction were bound to participate in its proceedings or to follow its decisions, a condition that still constrains much of international dispute resolution today.

The follow-up Hague Conference of 1907 attracted 44 state participants, much wider world participation than in 1899. Participants included not only most nations of Europe and North America, but also many nations of Latin America and some Asian and Middle Eastern states. The 1907 conference again failed to achieve broad-scope disarmament, but it resulted in 14 separate main agreements, with more specific “regulations” attached to some of them. These agreements covered a range of topics including the pacific settlement of disputes, limitations on the use of force to recover debts, steps required before commencing of hostilities, humane treatment of prisoners of war, prohibition on the use of weapons that cause unnecessary suffering, protecting the lives of citizens of enemy states, rights and duties of neutrals, extending the Red Cross protections of the Geneva Convention of 1863 to maritime warfare, and, as we have seen, prohibiting aerial bombardment.

In all, the Hague conferences of 1889 and 1907 produced a broad range of ambitious treaties designed to both lessen the likelihood of war (provisions for pacific settlement of disputes and the requirement that measures to be taken before commencing hostilities) and mitigate the harshness and suffering of war (such as the ban on aerial bombardment, the ban on weapons that cause unnecessary suffering, the requirement of protecting civilian lives). It is a rhetorical question to ask whether these provisions in fact resulted in either an end to war or greatly decreased suffering caused by war.

The Hague Agreements of 1907 involved a commitment to give warning before commencing hostilities, “in the form either of a reasoned declaration of war or of an ultimatum with conditional declaration of war.” (Hague III.) World War I began with Austria-Hungary following the letter but not the spirit of this requirement.

The 1907 Conventions also included a more extensive and sophisticated agreement on the peaceful resolution of international disputes (“Hague I”) than the 1899 agreement had produced. The contracting parties declared that they were “animated by the sincere desire to work for the maintenance of general peace,” were “resolved to promote by all the efforts in their power the friendly settlement of international disputes,” and were “desirous of extending the empire of law and of strengthening the appreciation of international justice.” Hague I established procedures for the mediation of international disputes by neutral countries; investigation by international commissions of inquiry, and arbitration by the “Permanent Court of Arbitration,” sitting at the Hague. As under the earlier agreement, Hague I’s international dispute resolution machinery suffered from fact that only countries that submitted to the court’s jurisdiction were bound to participate or abide by its decisions. Moreover, there was no mechanism for assuring compliance by even a participating country.

The participants in the Hague Peace Conference of 1907 planned to reconvene in 1915, but the third Hague Conference never happened. The great hopes of world peace had been shattered by world war. The unprecedented devastation and bloodshed that were the “Great War,” stand as an enduring monument to the failure of international law to achieve either of the two principle aims of the 1899 and 1907 Hague conferences: to resolve international disputes peacefully, and to mitigate the death, pain, destruction and sorrow of war when attempts at peaceful resolution fail.

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World War I

As noted, one of the Hague agreements of 1907 required states, before commencing hostilities, to give warning “in the form either of a reasoned declaration of war or of an ultimatum with conditional declaration of war.” Austria-Hungary followed the letter, but not the spirit, of that requirement when, after a Serbian national assassinated Austria-Hungary’s Archduke Ferdinand, Austria-Hungary delivered Serbia an ultimatum demanding, among other things, that Serbia agree to discharge unnamed Serbian officials at Austria-Hungary’s request and agree to permit Austro-Hungarian officials to participate in legal proceedings on Serbian soil against organizations hostile to Austria-Hungary.

Although Austria-Hungary’s ultimatum was unacceptable on its face, rather than rejecting it outright, Serbia offered to arbitrate the dispute — in accordance with principles for peaceful settlement agreed upon at the 1899 and the 1907 Hague conferences. Austria-Hungary responded to this peace offering by severing diplomatic relations, ordering partial mobilization, and, a few days later, declaring war on Serbia and commencing the bombardment of Belgrade. So began a war that eventually raged from the British Isles to Japan, from North Africa to Russia; lasted four and a half years; and killed an estimated 8,400,000 people.

Austria-Hungary delivered its unacceptable ultimatum and commenced hostilities against Serbia only after obtaining assurances from Kaiser Wilhelm II of Germany that Germany would come to the aid of Austria-Hungary if Austria-Hungary started a “preventive war” (what today might be referred to as a “preemptive war”) against Serbia. The war quickly expanded, based on hastily delivered ultimatums and previously existing mutual defense pacts, to include Russia, Germany, France, Belgium, Montenegro, Japan, and Italy and later many other countries including the United States. No one, it seems, had anticipated any such possibility. Nor was there any sustained and serious attempt by any of the initial belligerents to participate in the peaceful dispute resolution processes of the Hague Conventions before going to war. After all, it was their sovereign right. And of course there was no world organization capable of intervening to prevent or stop the burgeoning state violence.

The devastation of World War I gave rise to further efforts to prevent war and mitigate its harm. Some of the new efforts were so misguided, however, that far from ushering in a new era of world peace, they sowed seeds of an even more destructive war. Others laid the foundations for subsequent major developments in international law, including the United Nations.

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The Versailles Treaty

The Versailles Treaty both formally ended World War I and created the first truly international organization dedicated to world peace and cooperation, the League of Nations. It also established many conditions and requirements that contributed to World War II.

Although the proceedings at the Versailles Palace in 1919 had the purpose of negotiating a peace treaty to resolve issues in a war between two sides, only one side — and not all members of that side — were allowed at the table. After the Allies minus Soviet Russia had drafted the treaty, a German representative was called in. Germany’s objections had little effect, and on June 28, the parties, including Germany, signed the treaty. In hindsight, the consequences of a peace treaty negotiated only among the victorious Allies (minus Russia) might seem predictable.

The Versailles Treaty placed restrictions and demands on Germany some of which were reasonably aimed at preventing that country from preparing another aggressive war; others of which were humiliating to the German people or impossible to fulfill. The treaty provided for the continued occupation of parts of Germany by Allied forces for 15 years or more; required Germany’s demilitarization of the Rhine valley; forbade Germany to have an air force; and placed severe restrictions on its army and navy military equipment, including war ships and tanks. It did not, however, contain effective provisions for monitoring or enforcing these restrictions. The treaty required Germany to cede to its neighbors, including Czechoslovakia, Poland, Belgium and France, territory that Germany had previously claimed — territory that, in many cases, was home to large numbers of German citizens.

The Versailles treaty also required Germany to pay reparations over a period of 30 years for losses suffered by the Allies and their citizens as a result of “the war imposed upon them by the aggression of Germany and her allies.” The amount of the reparations was to be determined by an Allied Reparation Commission, and was set at 132 billion gold marks. The treaty also allowed the Allies to seize privately owned German property in their territories as contributions to the reparation fund. In 1921, the Allies determined that Germany’s war reparations liability was payable at a rate equal to 26% of the value of Germany’s exports. They demanded that Germany accede to this formula within six days, or else face occupation of the Ruhr Valley by Allied forces. Under this threat, Germany acceded and began making payments in accordance with the Allies’ demands. However, inflation soon made it impossible for Germany to keep up the crushing reparation payments.

Finally, the Versailles Treaty contained provisions for the prosecution of German war criminals, including a specific indictment of the deposed Kaiser Wilhelm II “for a supreme offense against international morality and the sanctity of treaties.” Wilhelm was to be tried before a special tribunal composed of one judge each from the United States, Great Britain, France, Italy and Japan. The chief difficulty with this scheme was that the Kaiser had already taken refuge in neutral Netherlands, which refused to hand him over.

Other war crimes provisions of the treaty also failed. The treaty asserted “the right of the Allied and Associated Powers to bring before military tribunals persons accused of having committed acts in violation of the laws and customs of war” and provided that Germany would hand over such persons, to be tried by military tribunals of the country against whose nationals they had committed crimes. In 1920, the Allies gave the German government a list of 896 alleged war criminals to be tried, including high ranking former German officials and officers. Germany responded that German people were so opposed to the idea they would mount an insurrection if their government complied, and some German military officers threatened to recommence the war. The Allies then shortened their list from 896 names to 45 and agreed that the 45 could be tried in a German court rather than in Allied courts. Germany agreed to try 12 of the 45. A handful were convicted and given light sentences. Some were acquitted on the ground that their otherwise criminal acts were in obedience to superior orders.39

The failure of the war crimes provisions of the Versailles Treaty is illustrative of a larger problem: the Allies in this and many other ways capitulated to Germany’s demands and failed to enforce the treaty’s provisions. This, too, seems predictable in hindsight, taking into consideration the oppressive and overreaching nature of some of the treaty’s restrictions and requirements, the fact that there still was no international organization with real monitoring and enforcement powers, and the fact that the victorious Allies, having just suffered a devastating war, were gun-shy and reluctant to take strong action to enforce the treaty in response to violations by a tyrant like Hitler.

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The League of Nations

The Allies who participated in the Paris Peace Talks of 1919 (Soviet Russia was excluded) adopted the Covenant of the League of Nations as part of the Versailles Treaty. U.S. President Woodrow Wilson took a leading role in drafting the Covenant, and some of its provisions reflect his famous “Fourteen Points.” Looking back over a period of nearly 90 years, the Covenant seems a strange mixture of lofty principles and inequitable, unworkable structure.

The preamble of the Covenant sets out principles and purposes of the League, above all, the achievement of world peace:

The High Contracting Parties,

In order to promote international co-operation and to achieve international peace and security

by the acceptance of obligations not to resort to war,

by the prescription of open, just and honourable relations between nations,

by the firm establishment of the understandings of international law as the actual rule of conduct among Governments, and

by the maintenance of justice and a scrupulous respect for all treaty obligations in the dealings of organized peoples with one another,

Agree to the Covenant of the League of Nations.


Presaging the Nuremberg Judgment, the Covenant also stated that a war of aggression is a “grave international delinquency.”

Addressing some of the underlying causes of war, Article VIII of the Covenant said, “[t]he Members of the League recognize that the maintenance of peace requires the reduction of national armaments to the lowest point consistent with national safety and the enforcement by common action of international obligations.” Moreover, “the manufacture by private enterprise of munitions and implements of war is open to grave objection. The Council shall advise how the evil effects attendant upon such manufacture can be prevented . . .” To assist in dealing with this evil, “The Members of the League undertake to interchange full and frank information as to the scale of their armaments, their military, naval and air programmes and the condition of such of their industries as are adaptable to war-like purposes.”

In 1925, at the League of Nations Council’s invitation, 24 states including Germany, the United States, and the USSR formed a preparatory commission for a general disarmament conference. The USSR made a proposal for complete, world-wide disarmament. The preparatory commission discussed and debated Russia’s disarmament proposal over the next three years, and finally rejected it in March, 1928. A disarmament conference was finally held in 1931 with delegates from 59 states in attendance. But little was accomplished there and Germany withdrew on the ground that it had not been granted equal status with other nations regarding armaments. The international disarmament conference met again in 1933, but by this time Adolph Hitler had become chancellor of Germany, and Germany took the position that it should be allowed to have prototypes of any weapons retained by other states, in violation of the Versailles treaty. When Germany didn’t get its way, it withdrew from the disarmament treaty and from the League of Nations.40
The reasons for the failure of the League of Nations and the Versailles Treaty to live up to their central goal of assuring world peace are many and complex, and are beyond the scope of this book except to identify a few factors that seem likely to have contributed to this monumental and tragic failure. First, Woodrow Wilson, who had contributed so mightily to the formation of the League, fell ill and was not able to garner the domestic political support necessary for the United States Senate to adopt the League Covenant. As a result, a major world power that had led the fledgling efforts to establish world peace was left out of the international body it helped to establish for that purpose. Second, Germany, which was the main object of the requirements and restrictions of the Versailles Treaty, had not been allowed to participate in the negotiation of that treaty and, as a result, many of its provisions were unduly or even impossibly harsh, particularly the monetary reparations provisions. This undue harshness in turn became powerful material for Hitler’s propaganda machine and contributed to Germany’s rearmament and withdrawal from the League of Nations. Third, the Treaty and the Covenant did not establish strong monitoring and enforcement provisions, a defect which greatly contributed to Nazi Germany’s rearmament in violation of numerous Treaty provisions. Fourth, the allied parties to the Treaty lacked the courage of their convictions and, in many cases, capitulated to Germany’s violations of the rearmament provisions and other provisions of Versailles. Finally, though the drafters of the League’s Covenant saw the armaments industry in general and profiteering in that industry in particular as an “evil” that must be addressed, it never was effectively addressed.

One seeming ray of hope for the avoidance of war during the post-World War I period, which at Nuremberg turned out to be key to convicting the Nazi leaders of “crimes against peace” (that is, aggressive war), was the Pact of Paris or Kellogg-Briand Pact of 1928. The Pact was negotiated primarily between U.S. Secretary of State Frank Kellogg and French Foreign Minister Aristide Briand and was entered into initially by some 15 nations including the United States, France, Germany, the United Kingdom, Italy, Japan. It eventually was ratified by a total of 69 states. In that pact, the signatory states agreed to “a frank renunciation of war as an instrument of national policy . . . to the end that the peaceful and friendly relations now existing between their peoples may be perpetuated.” In the Pact, the parties agreed to “condemn recourse to war for the solution of international controversies and renounce it as an instrument of national policy in their relations with one another.” In addition, “the settlement of all disputes or conflicts of whatever nature or of whatever origin they may be, which may arise among [the parties] shall never be sought except by pacific means.” The original parties invited all countries to become signatories in the hope of “uniting the civilized nations of the world in a common renunciation of war.”

In 1932, Henry Stimson, Secretary of State to President Franklin D. Roosevelt, stated that the renunciation of war between nations in the Kellog-Briand Pact meant that war “has become illegal throughout practically the entire world. It is no longer to be the source and subject of rights. It is no longer to be the principle around which the duties, the conduct, and the rights of nations revolve. It is an illegal thing.” [Quoted in Jackson, The Nurnberg Case, p. 15.]

The Kellogg-Briand Pact, however, created no mechanism with which to enforce the historic promises it contained. Thus, compliance (or non-compliance) was ultimately left to the political and military leaders of each nation.

As we know, the cumulative moral and legal authority of the Hague Conventions, the Versailles Treaty, the Covenant of the League of Nations and the Kellogg-Brand Pact was insufficient to stop Mussolini’s and Hitler’s rise to autocratic power and Germany’s rearmament and eventual invasion and conquest of most of Europe. In a sense, the solemn treaties were mere pieces of paper easily crushed under the steel treads of panzer tanks and shredded to ribbons by the furious propellers of Messerschmitt fighters.

Thus in the first forty-five years of the Twentieth Century, the principle of state sovereignty, which had dominated the Imperial Age, continued in large part to trump the world community’s new efforts to develop international controls over warfare. Nations continued to declare war when they wanted to, despite the solemn promises that had now been set down in more than one multilateral treaty not to use war as an instrument of diplomacy and to settle all international disputes only through peaceful means. Similarly, such treaty provisions as the prohibition against aerial bombardment, the prohibition of weapons that cause unnecessary suffering, and the requirement that civilian populations be protected, were overwhelmed, to a large extent, by the invention, sale and use of increasingly lethal weapons, including small-bore rifles, machine guns, poison gas, smokeless gun power, and airplanes capable of carrying out bombing sorties. There was, as yet, no international organization capable of reigning in these powerfully destructive, homicidal trends; nor had there been any in-depth exploration of the extent to which the profit motive in the arms industry propelled the same trends as the Covenant of the League of N had demanded. Do we have today either an in-depth understanding of the root causes of war, particularly its economic causes, or an organization capable of curtailing the incidence and destructiveness of war?

1 Burns Weston et al., eds., International Law and World Order, 3d ed., p. 32. If it is true that the law of war and peace is traceable to ancient Mesopotamia, it is a great irony of history that the same body of law finds itself imperiled there five millennia later.

2 Koran, 2:190 -91, quoted in Abdulazia Sachedina, “The Development of Jihad in James Johnson & John Kelsay, eds., Cross, Crescent & Sword, Greenwood Press, NY 1990, at 43.

3 [citation]

4 Quoted in Grotius at 814.

5 Quoted in Grotius at 79.

6 For a graphic description of the brutal mass homicide and cultural devastation involved in the Spanish conquest of the American Indians, from Spanish eye-witness accounts of Francisco Pizaro’s defeat of the Incan emperor Atahulpa in 1532, see Guns, Germs and Steel, the Fates of Human Societies by Jared Diamond, pp. 69 – 74.

7 Vitoria, Political Writings, p. 298.

8 Id, p. 265.

9 See id., pp. 247-251.

10 Id., p. 267.

11 Id., pp. 271 – 272.

12 Id., p. 271.

13 Id., p. 272.

14 Id. at 303.

15 Id.

16 Id.

17 Id. at 304.

18 Victoria, p. 306.

19 Grotius at ____.

20 Lawrence, TJ, A Handbook of Public International Law, 6th ed. at 89.

21 Quoted in Weston, et. al., International Law and World Order, Third ed., p. 296, fn. 18.

22 Quoted in Grotius, p 174.

23 Id.

24 Vitoria at 316.

25 Quoted in Lauterpacht in Weston et al., International Law and World Order, 3rd ed., p. 1255.

26 See p. ___, below.

27 Vitoria at 314 – 315.

28 Id. at 315.

29 Id. at 316.

30 Meron, Shakespeare’s Laws and Henry’s Wars, pp. 89-90.

31 Grotius, p. _____.

32 Lawrence at 122.

33 Id., p. 105, emphasis added.

34 Id., p. 109.

35 Id., p. 122.

36 Quoted in Grotius, 764.

37 Lawrence, pp. 103 – 104.

38 Id., p. 122.

39 Friedman, pp. 776-777.

40 Encyclopedia Britannica, Macro 21 “Twentieth Century International Relations,” p. 759.

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