War crimes trials are trials of persons charged with criminal violation of the laws and customs of war and related principles of international law. The practice began after World War I, when some German leaders were tried by a German court in the Leipzig War Crimes Trial for crimes committed during that war. After World War II the phrase referred usually to the trials of German and Japanese leaders in courts established by the victorious Allied nations.
The most important of these trials were held in Nuremberg, Germany, under the authority of two legal instruments. One, the so-called London Agreement, was signed by representatives of the United States, Great Britain, France, and the USSR in London on August 8, 1945; the other, Law No. 10, was promulgated by the Allied Control Council in Berlin on December 20, 1945.
The London Agreement provided for the establishment of the International Military Tribunal, composed of one judge and one alternate judge from each of the signatory nations, to try war criminals. Under the London Agreement, the crimes charged against defendants fell into three categories: crimes against peace, that is, crimes involving the planning, initiating and waging of aggressive war; war crimes, that is, violations of the laws and customs of war as embodied in the Hague Conventions and generally recognized by the military forces of civilized nations; and crimes against humanity, such as the extermination of racial, ethnic, and religious groups and other such atrocities against civilians.
On October 18, 1945, the chief prosecutors lodged an indictment with the tribunal charging 24 individuals with a variety of crimes and atrocities, including the deliberate instigation of aggressive wars, extermination of racial and religious groups, murder and mistreatment of prisoners of war, and the murder, mistreatment, and deportation of hundreds of thousands of inhabitants of countries occupied by Germany during the war.
Among the accused were the Nationalist Socialist leaders Hermann Göring and Rudolf Hess, the diplomat Joachim von Ribbentrop, the munitions maker Gustav Krupp von Bohlen und Halbach, Marshal Wilhelm Keitel, Grand Admiral Erich Raeder and 18 other military leaders and civilian officials. Seven organizations that formed part of the basic structure of the Nazi government were also charged as criminal. These organizations included the SS (Schutzstaffel, Defense Corps), the Gestapo (Geheime Staatspolizei, Secret State Police), and the SA (Sturmabteilung, Storm Troops), as well as the General Staff and High Command of the German armed forces.
The trial began on November 20, 1945. Much of the evidence submitted by the prosecution consisted of original military, diplomatic, and other government documents that fell into the hands of the Allied forces after the collapse of the German government.
The judgment of the International Military Tribunal was handed down on September 30-October 1, 1946. Among notable features of the decision was the conclusion, in accordance with the London Agreement, that to plan or instigate an aggressive war is a crime under the principles of international law. The tribunal rejected the contention of the defense that such acts had not previously been defined as crimes under international law and that therefore the condemnation of the defendants would violate the principle of justice prohibiting ex post facto punishments. It also rejected the contention of a number of the defendants that they were not legally responsible for their acts because they performed the acts under the orders of superior authority, stating that "the true test . . . is not the existence of the order but whether moral choice (in executing it) was in fact possible."
With respect to war crimes and crimes against humanity, the tribunal found overwhelming evidence of a systematic rule of violence, brutality, and terrorism by the German government in the territories occupied by its forces. Millions of persons were destroyed in concentration camps, many of which were equipped with gas chambers for the extermination of Jews, Gypsies, and members of other ethnic or religious groups. Under the slave-labor policy of the German government, at least 5 million persons had been forcibly deported from their homes to Germany. Many of them died because of inhumane treatment. The tribunal also found that atrocities had been committed on a large scale and as a matter of official policy.