Geneva and Hague Conventions

Photograph of hospital ship

National Archives #80-G-K-17386

Collectively known as the laws of war, the Geneva and Hague Conventions governed the behavior of most of the major powers that fought in the Second World War.  The Conventions had their roots in the classical Western concept of just war, which was derived from Roman philosophy, Christianized by Augustine of Hippo in the 5th century, and elaborated by Thomas Aquinas in the 13th century, Hugo Grotius in the early 17th century, and Emerich de Vattel in the early 18th century. The modern Conventions were closely associated with the Red Cross movement of the 19th century.

Just War. War is the use of force to settle conflicts between different political communities when diplomacy fails to achieve a peaceful settlement. Even at its least brutal, war implies the killing of enemy combatants and the destruction of enemy property. At its worst, war involves widespread death, destruction, pillage, rape, famine, epidemics, and other grievous disturbances of the social order. The horror of war has been recognized by Western thinkers from at least the time of Jesus of Nazareth in the first century, and means have been sought to prevent war or, if that was not possible, to ameliorate its horrors. This in turn led to a theory of just and unjust war and, under Grotius, to the foundation of international humanitarian law.

According to the theory of just war, the decision to wage war was just (jus ad bellum) only when it was done in response to a grievous wrong; when the nation going to war had not itself inflicted a comparable wrong on its enemy; and only as a last resort, after all other avenues of redress had failed. There had to be a reasonable chance of success and the moral benefit from going to war had to outweigh the evils that would likely follow from war making. Such a war could only be justly declared by a competent authority (such as a head of state) acting without ulterior motives.

In addition, the methods by which war was waged also had to be just (jus in bello). This meant limiting death and destruction to the minimum necessary to defeat the enemy's military forces and thereby force the enemy to submit. Internecine warfare ("war to the death", waged to physically annihilate the enemy) was particularly forbidden. A distinction was made between lawful combatants and noncombatants, with only the former being legitimate targets and only so long as they continued to offer resistance. Furthermore, means of inflicting harm were limited to what was necessary to render the enemy hors de combat, so that weapons designed to inflict suffering beyond what was necessary to take an enemy soldier out of combat were unjust.

Classical just war theory did not sharply distinguish between jus ad bellum and jus in bello. A soldier was justified in killing only when he fought in a just cause using just means; anything else was murder. Since, at most, one side in a war could be in the right, this was an invitation for the victors to slaughter or enslave the losers, whom the victors could argue were obviously in the wrong and therefore guilty of murder. The particular contribution of Vattel was to separate jus in bello from jus ad bellum by arguing that, given the uncertainties in all human affairs, no side in a war could be entirely sure they were in the right. It was therefore better to protect captives of both sides so long as they had fought by just means. The pragmatic value of Vattel's philosophy for avoiding internecine warfare was obvious, and his works greatly influenced the American founders and their contemporaries in Europe.

What came of all this was the Enlightenment laws of war, which regarded war as a trial of arms to settle differences between sovereigns. These laws of war sought to leave ordinary civilians as completely untouched by war as possible. Their persons were protected and their property was immune from seizure or destruction. Only soldiers were legitimate targets and only public property of military value could be seized or destroyed. War was strictly a matter between the sovereigns and the relatively small bodies of professional soldiers they employed. The military tactics of the 18th and early 19th century, which were designed for closely massed formations of soldiers armed with relatively inaccurate, short-range firearms with a slow rate of fire, were particularly amenable to this philosophy of war.

The growing industrialization of war in the latter half of the 19th century threatened to break down the laws of war. The Crimean War, the American Civil War, and the Italian War of 1859 all showed that combat with modern weapons was more terrible than ever, and the rise of mass armies armed with mass-produced weapons blurred the difference between the public and private.

Establishment of the Conventions. Prior to the American Civil War, the laws of war were a part of customary international law, which consisted of uncodified practices widely accepted as law by the great powers. The first codification of the customary laws of war was likely the Lieber Code, signed on 24 April 1863 by Abraham Lincoln as General Order 100 of the Union Army. The Lieber Code was drafted by Franz Lieber, a German-American lawyer, veteran of the Battle of Waterloo, and editor of the hugely successful Encyclopedia Americana, who was assisted by several high-ranking officers from the War Department.

The Lieber Code was in part a response to the claim by the Confederacy that the Emancipation Proclamation was a violation of the customary laws of war, because it "pillaged" private property (that is, the emancipated slaves) and threatened to provoke a servile insurrection that would know no humanitarian restraints. The Confederacy declared that black Union soldiers and their white officers would be denied prisoner of war status, and they refused to exchange black prisoners on the same basis as white prisoners.

The Lieber Code forbade a "no quarter" policy or the use of poison or torture, and it laid down rules for humane treatment of prisoners of war and of civilians in occupied territory. However, by comparison with the Enlightenment laws of war, it was a harsh code, giving considerable latitude to military necessity. Lieber himself was of the opinion that wars ought to be sharp to ensure they would be short and infrequent. In other words, Lieber believed that war fought by the gentle rules of the Enlightenment would actually be less humanitarian, because it would be frequent and long lasting.  As a U.S. Army regulation, the Lieber Code had no formal international standing, but it greatly influenced the subsequent development of international humanitarian law.

The first Geneva Convention was prompted largely by the carnage of the Italian War of 1859. Unlike the Lieber Code, it took the form of an international treaty, signed in August 1864. It established rules for the protection of the wounded and of medical personnel.  The latter were granted complete immunity so long as they did not engage in any military activity.  There were also provisions for treatment of wounded prisoners and for return of unwounded prisoners on condition that they not again bear arms. The first Geneva Convention also established the Red Cross (a red cross on a white field) as an international symbol designating medical personnel and facilities.

The first Hague Conference, which concluded in July 1899, adopted three lengthy conventions and three declarations.  The first Hague Convention was aimed at preventing war, and it set down rules for international mediation and arbitration of disputes.  It established a framework for mediation through the good offices of a neutral power, established rules for international commissions of inquiry, and established a Permanent Court of Arbitration at The Hague. However, the jurisdiction of the Court was limited to cases where both parties agreed to arbitration.

The second Hague Convention codified most of the laws of war recognized in the first half of the 20th century. It required military forces, including militias, to serve under responsible officers of a government and to wear distinctive insignia, visible from a distance.  Rules for humane treatment of prisoners of war were laid down.  Prisoners of war were to be treated the same as regards food, clothing, shelter, and pay as the captor’s own forces.  Military activities against undefended cities or against unarmed civilians were forbidden, as was pillage or unnecessary destruction of enemy property. 

The third Hague Convention governed hospital ships.  It thus extended the protections of the First Geneva Convention to medical personnel at sea.

The declarations adopted by the first Hague Conference imposed a five-year ban on bombing from balloons, a prohibition on poison gas projectiles, and a prohibition on dum-dum bullets. The ban on dum-dum bullets, which expand on impact with human flesh to inflict more grievous wounds, reflected the concept that jus in bello forbade the use of weapons deliberately intended to inflict suffering beyond that necessary to render an enemy hors de combat.

The second Hague Conference, which concluded in October 1907, adopted twelve conventions.  These required that hostilities open with a declaration of war or after expiration of an ultimatum with conditional declaration of war; set out rights and obligations of neutrals; established a right of departure for enemy merchant shipping; established procedures for seizure of ships on the high seas; and established rules for the use of mines and for naval bombardment of shore targets. These conventions were aimed at reducing the likelihood of accidental war or the drawing of neutrals into an existing conflict.

Following the First World War, the major powers sought a further expansion of the laws of war. The second Geneva Convention was signed in February 1928 and prohibited chemical and biological warfare, and the third Geneva Convention, signed in July 1929, greatly expanded the rules governing prisoners of war.

By August 1939, all the Western powers that would play a significant role in the Pacific War had ratified the Geneva and Hague Conventions. Japan had signed all the Conventions, but did not ratify the third Geneva Convention on prisoners of war. This was largely due to opposition from the Japanese Army, which had begun to harden in its attitude towards surrender. Russia also refused to adhere to the third Geneva Convention, and both Russia and Japan would become notorious for their mistreatment of prisoners of war.

The wide acceptance of the principles of jus in bello codified in the Conventions raises the question of why nations that could agree to wage war according to civilized rules could not avoid going to war in the first place. The experience of the First World War also suggested that no grievance between nations could justify the waging of modern warfare, with all its horrors, for its redress. The signatories to the Kellogg-Briand Pact of 1928 accordingly renounced war as an instrument of national policy, and by 1939 every power that would play a significant role in the Pacific War had adhered to the Pact. However, the U.S. Senate resolution ratifying the Pact included an interpretation that the Pact did not preclude self-defense nor impose an obligation to intervene against a party violating the Pact. Thus, the Pact appeared to establish the principle that only defensive war is justifiable, but without establishing an effective means of its own enforcement.

Given that the most destructive war in human history broke out just eleven years after adoption of the Kellogg-Briand Pact, the Pact has sometimes been dismissed as hopelessly idealistic. This is not entirely fair. The principle that war is too terrible to contemplate except as a direct response to aggression by a rogue state was, if anything, reinforced by the experience of the Second World War, and this has remained a principle of international law since. The Second World War came about, in part, because the Axis powers adopted a militaristic philosophy that glorified war, implicitly rejecting the entire philosophical framework of jus ad bellum represented by the Pact. The statement in a Japanese Army pamphlet of 1934 that "War is the father of creativeness and the mother of culture" (Browne 1967) was irreconcilable with the renunciation of war that characterized the liberal West in 1939.

The Conventions in the Pacific War. The Western powers involved in the Pacific War had all adhered to the Geneva and Hague Conventions, and, though Japan never ratified the third Geneva Convention, she had ratified the Hague Conventions and announced in 1942 that she would abide by all the Conventions. There are many reasons to criticize the Tokyo war crimes tribunals, but the notion that the laws of war were not binding on Japan is probably not one of them. 

The Conventions did not fare well in the Second World War, and not only in the hands of the Axis, though their violations were much more pervasive than those of any of the Allies except Russia. The philosophy of war as a positive good, held by the leadership of both Japan and the European Axis, underwrote much of the Axis brutality. That Hitler, who had experienced trench warfare in France, could champion a philosophy that glorified war, is perhaps an indication of the abnormal psychology of the man. The Japanese had not experienced the trench warfare of Europe, and recollections of the carnage of the Russo-Japanese War of 1905 had faded, but the Japanese had witnessed the brutality of the warlord struggles in China in the 1920s. Edgerton (1997) has suggested that this actually had the opposite effect of what one might expect, contributing significantly to the increasingly brutal character of the Japanese Army.

This tendency of atrocity to beget atrocity may in turn help explain the lapses on the part of the Allies. However, other factors were in play. The very doctrine of jus ad bellum that condemned aggressive war, and gave the Allies their strongest claim to the moral high ground, also led the Allies to view the Axis as international criminals. This view certainly had its merits, as did the Allied insistence on unconditional surrender; but it also encouraged a hardening of attitudes on the part of the Allies. Combined with a not unrealistic fear of the dreadful consequences of defeat at the hands of the Axis, this led to an Allied willingness to regard such extreme measures as the fire bombing of cities and the nuclear attacks on Hiroshima and Nagasaki as justified by military necessity, even though such measures appeared to constitute wanton destruction and the targeting of noncombatants. But one can reasonably ask what better alternative the Allies were left with, given Japanese intransigence in the last months of the war, as exemplified by the employment of kamikazes and the rapid military buildup in Kyushu.

Charges against the Allies of failing to make war by honorable means ring hollow given Japanese conduct in China, including the rape of Nanking and the Japanese bombing of Chungking and other cities. The Japanese attack on Pearl Harbor violated the convention on initiation of hostilities, and Japanese mistreatment of prisoners of war was notorious.  That Japan used chemical and biological weapons in China is now well established.  American commanders in the Pacific were deeply suspicious of the heavy hospital ship traffic under the Japanese flag, a suspicion that was confirmed by decoded Japanese messages showing the Japanese were attempting to use the hospital ships to transport troops. However, the great secrecy surrounding cryptanalysis meant that the Allied commanders could neither act on nor publicly disclose this violation, which did not come to light until the 1990s (Weinberg 1994).


Avalon Project (accessed 2009-6-13)

Browne (1967)
Cook and Cook (1992)

Edgerton (1997)

Weinberg (1994)

Witt (2012)

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