The London Charter was part of an agreement concluded August 8, 1945, by the World War II allies to prosecute the "major war criminals of the European Axis." Several Allies had considered the possibility of summarily executing Nazi leaders. The United States then pressed for trials, and the other Allies agreed. Parties to the agreement were France, the United Kingdom, the USSR, and the United States. The Charter provided for the creation of a court, the International Military Tribunal (IMT), composed of four judges, one from each signatory state. The Charter gave the Tribunal jurisdiction over three categories of offense: crimes against peace, war crimes, and crimes against humanity.
At the conclusion of World War I, the Treaty of Versailles had called for trial of the German Kaiser "for a supreme offense against international morality and the sanctity of treaties," but that trial was never held. The London Charter represented the first successful attempt to carry through with trials, at the supra-national level, of major figures accused of responsibility for an aggressive war and for particular atrocities perpetrated during that war.
The category of war crimes included offenses found in established principles of customary international law, which had previously been applied by courts of individual countries to prosecute military personnel. War crimes were defined in the Charter to include "murder, ill treatment, or deportation to slave labor, murder or ill treatment of prisoners of war, and wanton destruction of cities, towns, or villages."
The category of crimes against humanity was less well grounded in customary international law. The Charter defined it as "murder, extermination, enslavement, deportation, and other inhumane acts committed against any civilian population before or during the war or persecutions on political, racial, or religious grounds in execution of or in connection with any crime within the jurisdiction of the Tribunal, whether or not in violation of the domestic law of the country where perpetrated."
The category of crimes against peace included the "planning, preparation, initiation or waging of a war of aggression." This category was only weakly grounded in customary international law. War among states was first prohibited by treaty in the 1920s, and even if war was wrongful on the part of a state, as legal experts of the time argued, it was not clear that it was wrongful as a penal offense for which an individual could be held responsible.
Importantly, the London Charter stipulated that the official position of an accused individual provided no immunity from prosecution, and that superior orders were not a defense, although they might be taken into account to mitigate punishment.
The London Charter provided that if an accused acted as a member of a group, the Tribunal could declare the group a "criminal organization." The effect of such a declaration was that in subsequent trials to be held in the four zones of occupation of Germany, the court of an occupying power would be authorized to try persons for membership in such an organization.
The prosecution team as stipulated by the Charter was composed of a chief prosecutor from each of the four signatory states. Rights of defendants were specified, including receipt of a particularized indictment, the opportunity to present evidence and cross-examine witnesses, translation of proceedings into a language the accused would understand, and the right to be represented by counsel or to represent oneself.
The London Charter had a major impact on the subsequent development of internationally defined crimes. The category of crimes against humanity served as the basis for conceptualizing the category of genocide, which was defined and criminalized in the UN Convention on the Prevention and Punishment of the crime of genocide, adopted in 1948.
The United Nations (UN) General Assembly tasked its International Law Commission with drafting a code of offenses based on the London Charter, with the idea that it might be adopted as a treaty. Although this effort eventually came to naught, the categories of be international crime outlined in the London Charter were used, with modifications, in the crime definitions written into the charters of the two tribunals that the UN Security Council formed in the 1990s to address atrocities committed in Yugoslavia and Rwanda. These categories also served as the model for the crime definitions in the Statute of the International Criminal Court (ICC), which came into force in 2002.
The London Charter was also a precursor to the concept of human rights law that emerged in international society after World War II. Whereas the London Charter placed responsibility on leaders, human rights law ascribed it to states, establishing an elaborate network of mechanisms to ensure that states would not mistreat individuals.
International Military Tribunal (1947). Trial of the Major War Criminals before the International Military Tribunal. 42 vols. Nuremberg: International Military Tribunal.
Office of Chief Counsel for the Prosecution of Axis Criminality. Nazi Conspiracy and Aggression. 8 volumes. Washington, D.C.: U.S. Government Printing Office.