It wasn't beyond the law at the Nuremburg trials, nor for Eichmann in Israel nor in trials at the Hague.
The Hague is home to the International Criminal Court (ICC), which tries individuals for genocide, crimes against humanity, war crimes, and the crime of aggression. It also hosted the International Criminal Tribunal for the former Yugoslavia (ICTY), a temporary court that operated from 1993 to 2017.
Some notable recent and ongoing cases at the ICC include the conviction of Ali Muhammad Ali Abd-Al-Rahman for war crimes in Darfur and trials related to situations in Georgia. The ICTY tried high-level political and military leaders from the Yugoslav Wars.
International Criminal Tribunal for the former Yugoslavia (ICTY)
What it was: A temporary United Nations court that operated from 1993 to 2017 to prosecute those responsible for war crimes committed during the Yugoslav Wars.
Cases: The ICTY indicted over 160 people, including heads of state and military leaders.
Slobodan Milosevic: The former President of Serbia and Yugoslavia was tried for war crimes, but died before a verdict was reached.
Ratko Mladic: Former commander of the Bosnian Serb Army, was arrested in 2011 and later convicted.