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Law of war

International regulations of warfare

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  • 4 chapters
Facsimile of the original first Geneva Convention from 1864, on loan to the International Red Cross and Red Crescent Museum in Geneva, Switzerland.
Kevin Quinn, Ohio, US · CC BY 2.0

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Through International law, War and Proportionality (law)

While international humanitarian law (IHL, or jus in bello) concerns the rules and principles governing the conduct of warfare once armed conflict has begun, jus ad bellum (an aspect of public international law) pertains to the justification for resorting to war and includes the crime of aggression. Together the jus in bello and jus ad bellum comprise the two strands of the laws of war governing all aspects of international armed conflicts. The law is mandatory for nations bound by the appropriate treaties. There are also other customary unwritten rules of war, many of which were explored at the Nuremberg trials. IHL operates on a strict division between rules applicable in international armed conflict and internal armed conflict.

The law of war is considered distinct from other bodies of law—such as the domestic law of a particular belligerent to a conflict—which may provide additional legal limits to the conduct or justification of war.

History

Ancient origins

States have long employed law to limit their conflicts. The first traces of a law of war come from the Babylonians. It is the Code of Hammurabi, king of Babylon, which in 1750 B.C., explains its laws imposing a code of conduct in the event of war:

I prescribe these laws so that the strong do not oppress the weak.

An example from the Book of Deuteronomy 20:19–20 limits the amount of environmental damage, allowing only the cutting down of non-fruitful trees for use in the siege operation, while fruitful trees should be preserved for use as a food source. Similarly, Deuteronomy 21:10–14 requires that female captives who were forced to marry the victors of a war, then not desired anymore, be let go wherever they want, and requires them not to be treated as slaves nor be sold for money.

Religious frameworks

In the early 7th century, the first Caliph Abu Bakr, while instructing his army, laid down rules against the mutilation of corpses, killing children, women, and the elderly. He also laid down rules against environmental harm to trees and slaying of the enemy's animals:

Stop, O people, that I may give you ten rules for your guidance in the battlefield. Do not commit treachery or deviate from the right path. You must not mutilate dead bodies. Neither kill a child, nor a woman, nor an aged man. Bring no harm to the trees, nor burn them with fire, especially those which are fruitful. Slay not any of the enemy's flock, save for your food. You are likely to pass by people who have devoted their lives to monastic services; leave them alone.

In the history of the early Christian church, many Christian writers considered that Christians could not be soldiers or fight wars. Augustine of Hippo contradicted this and wrote about 'just war' doctrine, in which he explained the circumstances when war could or could not be morally justified.

In 697, Adomnan of Iona gathered Kings and church leaders from around Ireland and Scotland to Birr, where he gave them the 'Law of the Innocents', which banned killing women and children in war, and the destruction of churches.

Apart from chivalry in medieval Europe, the Roman Catholic Church also began promulgating teachings on just war, reflected to some extent in movements such as the Peace and Truce of God. The impulse to restrict the extent of warfare, and especially protect the lives and property of non-combatants continued with Hugo Grotius and his attempts to write laws of war.

Early modern period

In part because of Grotius and the development of the modern law of nations, for almost three centuries after the conclusion of the Thirty Years War Europe entered a period of what may be termed “the golden age of the jus in bello, of frame positive constraints on the conduct of war." Generally, international conflicts in Europe were set piece battles waged by professional armies fighting for limited and fixed political objectives. Civilians and civilian populations were usually left more or less unharmed by military forces.

The Treaty of Armistice and Regularization of War signed on November 25 and 26, 1820, between the president of the Republic of Colombia, Simón Bolívar and the Chief of the Military Forces of the Spanish Kingdom, Pablo Morillo, is the precursor of the International Humanitarian Law. The Treaty of Guadalupe Hidalgo, signed and ratified by the United States and Mexico in 1848, articulates rules for any future wars, including protection of civilians and treatment of prisoners of war. The Lieber Code, promulgated by the Union during the American Civil War, was critical in the development of the laws of land warfare.

As the 19th century unfolded, the effort to codify and develop the law of war and to control the use of arms became even more earnest. There were profound hopes that war might eventually be abolished since civilization had become so advanced. Such hopes were linked to the idea that international adjudication and arbitration could come to replace war as a means of international dispute settlement. In 1864, 12 countries signed the Geneva Red Cross Convention, protecting hospital and ambulance crews.

Between 1899 and 1907, many various and detailed Hague Conventions were issued that were a produce of two Hague Peace Conferences. The first conference was convened in 1899, following a call by Tsar Nicholas II in 1898, who declared:

[T]hat the present moment would be very favorable for seeking, by means of international discussion, the most effectual means of insuring to all peoples the benefits of a real and durable peace, and, above all, of putting an end to the progressive development of the present armaments.

Historian Geoffrey Best called the period from 1856 to 1909 the law of war's "epoch of highest repute". The defining aspect of this period was the establishment, by states, of a positive legal or legislative foundation (i.e., written) superseding a regime based primarily on religion, chivalry, and customs. It is during this "modern" era that the international conference became the forum for debate and agreement between states and the "multilateral treaty" served as the positive mechanism for codification.

20th century development

The Nuremberg war crimes trials judgment on "The Law Relating to War Crimes and Crimes Against Humanity" held, under the Nuremberg Principles, that treaties like the Hague Convention of 1907, having been widely accepted by "all civilised nations" for about half a century, were by then part of the customary laws of war and binding on all parties whether the party was a signatory to the specific treaty or not.

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