Rules of War

The modern rules of war trace their origins to the chivalric practices of medieval Europe. Feudal knights were bound by the law of chivalry, a customary code of conduct that could be enforced in local courts throughout western Europe by a military commander of any nation. Premised on notions of justice and fairness, the law of chivalry gave birth to the distinction between soldier and civilian and the idea that women, children, and older persons should be shielded from the bloody fields of combat. The Roman Catholic Church also influenced the development of these rules, differentiating between just and unjust wars and denouncing certain weapons as odious to God.

CODIFICATION of the rules of warfare began in the nineteenth century. In 1862 President ABRAHAM LINCOLN commissioned Francis Lieber to draft a code of regulations summarizing the laws and usages of war. A year later, Lieber submitted a draft that the EXECUTIVE BRANCH promulgated as General Orders No. 1, entitled Instructions for the Government of Armies of the United States in the Field. Known as the Lieber code, this systematic articulation of the rules of war remained the official pronouncement of the U.S. Army for more than a half a century. It addressed the concept of military necessity, detailed the rights of prisoners, noncombatants, and spies, and discussed the use of poisons, unnecessary violence, and cruelty.

In 1864 the codification movement took on an international flavor when 12 nations signed a Convention for the Amelioration of the Condition of the Wounded in Armies in the Field, 129 Consol. T.S. 361, the first of a series of Red Cross initiatives for this purpose. In 1899 the United States, Mexico, Japan, Persia (now Iran), Siam (now Thailand), and 19 other nations, including all major European powers, signed a Convention with Respect to the Laws and Customs of War, 187 Consol. T.S. 429, an initiative that followed the broad outlines of the Lieber code and also addressed the relationship between an occupying power and noncombatant civilian inhabitants. In 1914 the Lieber code was replaced by an army manual entitled The Law of Land Warfare, which continued in the early 2000s to be enforced.

Codification of the international rules governing land, sea, and air warfare accelerated following the conclusions of World Wars I and II, the KOREAN WAR, the VIETNAM WAR, and the many other hostilities that took place during the twentieth century. In addition to building upon the principles previously established, this period witnessed the creation of several new concepts, including certain categories of WAR CRIMES, such as crimes against peace and crimes against humanity.

Crimes against peace are committed by persons who plan or wage aggressive wars. Crimes against humanity are committed by persons who knowingly participate in the deportation, enslavement, persecution, or programmatic extermination of certain segments of society during times of war. Soldiers, military leaders, political officials, members of the judiciary, industrialists, and civilians are all subject to prosecution for violating any of these rules of war.

Leaders and officials who wage aggressive war, disregard the territorial or political independence of another state, or violate the express terms of a peace settlement may be prosecuted as war criminals under the United Nations Charter. They may also be prosecuted under the Nuremberg principles, derived from the NUREMBERG TRIALS after WORLD WAR II in which the Allied powers tried 24 leading Nazis for an assortment of war crimes, including crimes against peace and crimes against humanity. The Allies later prosecuted more than a hundred German civilians, including industrialists, doctors, and judges, who were enlisted by the Nazis to further their system of terror.