What lesson can we learn from the Nuremberg trials today?

Just after the end of World War II, the victorious Allied powers prosecuted high-ranking officials of the defeated Nazi regime before an International Military Tribunal in the city of Nuremberg. In the more than seventy years that have passed since then, people have drawn several different lessons from the Nuremberg trials. Some emphasize the importance of preventing another Holocaust before it happens, while others focus on the necessity of ensuring justice even in the most extreme circumstances. The most important lesson of the Nuremberg trials may be that the crimes of the Holocaust were committed by relatively ordinary human beings rather than cartoonish monsters.
Approximately 60 million people died in World War II, including around 6 million Jewish people murdered in the Holocaust. During the Nuremberg trials, Nazi propagandist Julius Streicher was convicted of crimes against humanity despite having had no direct involvement in the mass murders committed by the Nazi regime. Streicher was convicted solely for having incited genocide in the pages of the newspaper he published. The United Nations went on to declare incitement of this type a crime under international law in its 1948 Genocide Convention. Robert R. Singer, former CEO of the World Jewish Congress, has argued in The Times of Israel that Streicher’s conviction is a precedent that ought to be more broadly applied and that the lesson we should be drawing from Nuremberg is to prevent another Holocaust before it happens rather than punishing the war criminals after the fact.
Some commentators have questioned the integrity of the Nuremberg trials themselves. According to Michael P. Scharf of the Case Western Reserve University School of Law, the legitimacy of the Nuremberg trials can be criticized on four primary grounds. First, only the defeated were brought to trial even though war crimes were committed by the Allies as well. Second, the defendants were charged with crimes that had never been considered crimes before the trial, such as waging a war of aggression. Third, there were not enough legal protections for the accused. Fourth, there was no appeal in the event of conviction. According to Scharf, one lesson we should draw from the Nuremberg trial is the importance of addressing these concerns in any future international war crimes trials.
Professor Emeritus Alan Goldberg of the School of Education, as quoted in the Syracuse University News article “Understanding the Nuremberg Trial and Its Lessons,” emphasizes the importance as well as the discomfort of seeing the Nazi defendants as human beings instead of symbols of absolute evil. It might be easier or more comforting to think of the Nazi war criminals as inhuman monsters, but this would prevent us from examining how the Holocaust was allowed to happen in the first place. In Stuart Schulberg’s documentary “Nuremberg: Its Lesson for Today,” the Nazi leaders on trial at Nuremberg are shown as relatively ordinary human beings—men sitting on a bench and trying to cover their faces with their hands as they hear the charges against them. To achieve the goal of preventing another Holocaust before it happens, we must understand that human beings like us are capable of the most horrific crimes. This is arguably the most important and enduring lesson of the Nuremberg trials.
https://blogs.timesofisrael.com/has-the-world-really-learned-the-lessons-of-nuremberg/

https://news.syr.edu/blog/2013/04/16/understanding-the-nuremberg-trial-and-its-lessons-85448/