With the recent move by President Trump to issue pardons to some U.S. soldiers that were either charged with or convicted of war crimes, it is fitting that the largest war crimes trials in history and the ones that changed how the world treats war crimes began on this day in 1945.

These trials would last from November 20, 1945 to October 1, 1946. Of the initial 24 men tried, 12 would be found guilty (one in absentia) and hanged. Of the rest, three were acquitted; one was found unfit for trial by reason of bad health; one committed suicide before the trial could commence; and one was indicted incorrectly and not tried. The rest were given long prison sentences. 

This trial was significant because something of this scope had never been attempted before. (Of a smaller scale, in the United States, Henry Wirz was convicted of war crimes and executed over the maltreatment of Union prisoners of war at Andersonville prison during the Civil War. The Turks also held a trial in 1920 for the 1915-1916 Armenian Genocide.) 

But besides its scope, another novelty of the trial was that four different legal systems (British, French, American, and Soviet) would be applied to try the alleged illegal and criminal activities of a fifth nation (Nazi Germany). Therefore, the rules of the trial had to be worked out beforehand. 

After the Germans surrendered on May 7, 1945, the four countries went to work on the laws and procedures that they would use to conduct the trial. Eventually, on August 8, 1945, the Allies agreed on the London Charter of the International Military Tribunal (IMT). 

The London Charter defined three categories of crimes: 

  • Crimes Against Peace (which included the planning, preparing, starting or waging wars of aggression or wars in violation of international agreements) 
  • War Crimes ( violations of customs or laws of war, including improper treatment of civilians and prisoners of war) 
  • Crimes Against Humanity (including murder, enslavement or deportation of civilians or persecution on political, religious or racial grounds). 

When producing the charter, the Allies decided that civilian officials as well as military officers, could be accused of war crimes.  The results of the trial were important in establishing principles of international law regarding war crimes, crimes against humanity and wars of aggression. The trial was also instrumental in the eventual (50 years later) development of the International Criminal Court.

The Nuremberg trials also tried genocide for the first time. The Nazis were tried for “the extermination of racial and national groups, against the civilian populations of certain occupied territories in order to destroy particular races and classes of people and national, racial, or religious groups, particularly Jews, Poles, and Gypsies and others.”