Chile's former dictator Augusto Pinochet in Santiago, Chile, 1996, (left) and U.S. President Donald Trump speaks at a rally on Jan. 6, 2021 (right).AFP PHOTO/REUTERS

Philippe Sands, KC, is professor of law at University College London and a visiting professor at Harvard Law School. He is the author of East West Street, and his latest book is 38 Londres Street. This essay is a modified excerpt of the speech he delivered at Massey College in October, 2025, for the third annual Irving Abella Lecture.

The Nuremberg Tribunal in many respects is the beating heart of the story I’m going to tell you today, which is drawn from my latest book, 38 Londres Street. When the Second World War came to an end, there was a commitment between various governments, including the government of Canada, to set up an international tribunal. This was not simply – as Winston Churchill had originally proposed – a means of lining up the top Nazis and executing them: Franklin Roosevelt and Joseph Stalin persuaded him that something else was needed.

The creation of a tribunal, the first international tribunal in human history, was the consequence. One of the issues that had to be addressed was whether anyone who appeared before that tribunal would be entitled to claim immunity on the basis that the conduct in which they were alleged to have engaged was official conduct. At that point, in 1945, the immunity of a serving or former head of state was considered to be absolute, so the issue of what to do with immunity was central.

The point was addressed explicitly in a letter written to president Harry Truman by Robert Jackson, on leave as a justice of the United States Supreme Court to serve as chief prosecutor at Nuremberg. Jackson considered immunity to be an “obsolete” doctrine, a “relic” of the era of the divine right of kings. Immunity, he told Truman, was inconsistent with the position taken by the U.S. toward its own officials.

Jackson’s comment is telling because it appears to presume that the U.S. Constitution would provide no immunity for a former American president who crossed the line into criminality. Jackson worried that giving immunity to former leaders would produce a paradox whereby legal responsibility would be the least where power was the greatest.

Thus, Nuremberg established the principle there would be no immunity, and that was a first. It was later taken forward by other international courts, such as the International Criminal Court and tribunals, such as those held in the aftermath of crimes committed in Rwanda and the former Yugoslavia.

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What remained unclear was what would happen if a former head of state accused of an international crime was brought before a national court in a country other than his own.

That would be addressed for the first time when Augusto Pinochet, Chile’s former head of state, travelled to Britain to go shopping, buy books, and have tea with his friend Margaret Thatcher. On the evening of Oct. 16, 1998, he was arrested whilst recovering from a minor back operation in the London Clinic in Devonshire Place. The arrest was made pursuant to a warrant issued by a Spanish judge, Baltasar Garzón, who alleged that Mr. Pinochet had committed crimes against humanity, genocide and torture, and had disappeared people.

Margaret Thatcher and former Chilean leader Gen. Augusto Pinochet are seen in this file footage taken in March, 1994, during a private meeting in Santiago.REUTERS

After his arrest, Mr. Pinochet’s lawyers argued that he had absolute immunity from the jurisdiction of the English courts. And eventually, in March, 1999, the House of Lords, the highest judicial court in Britain, ruled that Mr. Pinochet did not have immunity from the jurisdiction of the English courts in relation to certain crimes relating to torture. The fact that his conduct may have been characterized as official conduct was not sufficient to get him off the hook. And that ruling by the House of Lords, which was the third ruling in relation to Mr. Pinochet, was premised on the fact that Chile, Spain and Britain were all parties to the 1984 Convention Against Torture, which provided explicitly that any person who is alleged to have committed torture and who is found in the jurisdiction of a country that is a party to the treaty may be prosecuted for the international crime of torture, or extradited to a country where that person will be prosecuted.

The complex and novel issue before the House of Lords was........

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