Could the victors fairly judge the leaders they'd defeated?

Partly. At Nuremberg the victors gave Nazi Germany's leaders a real trial, with evidence, defense lawyers and even acquittals. But only the defeated side was judged, and that criticism has never gone away. After the war, the Allies disagreed about what to do. The Soviet Union wanted a show trial. Britain preferred summary executions. In mid-1945, France, the Soviet Union, Britain and the United States agreed instead on a joint international tribunal in Nuremberg.

From November 1945 to October 1946, it tried 22 leading Nazis and six organizations. Some charges were new. Planning and waging a war of aggression became "the supreme international crime," although no law had made individuals criminally responsible for aggression before. "Crimes against humanity" covered the murder, extermination, enslavement and deportation of civilians, and the Holocaust was a major focus. Those charges held up best: only two defendants charged with them were acquitted.

Twelve defendants were sentenced to death. Ten were hanged on 16 October 1946; Hermann Göring killed himself the day before. Seven went to prison, and three were acquitted, to observers' surprise. In 1946, 78 percent of Germans called the trial fair. Four years later only 38 percent did, as more came to see it as "victor's justice."

The critics had a point. Allied actions, such as the Soviet pact with Nazi Germany and the expulsion of millions of Germans from Central and Eastern Europe, would have counted as crimes under the tribunal's own charter, yet were never tried. Later, as the Cold War set in, the United States released early most of the men convicted in its follow-up trials at Nuremberg. Still, the principle that individuals can be held responsible for violating international law is seen as the true beginning of international criminal law.