It is widely believed that the Allied powers were in the dark about the “final solution” — the Nazi campaign to exterminate Europe’s Jews — until the discovery of the death camps, strewn with corpses and emaciated inmates, at the end of World War II.

Yet Russia, Britain and the United States publicly declared their knowledge of the Holocaust horrors in late 1942 and called for creation of a United Nations commission to investigate them — even as the US State Department suggested that their joint statement omit estimates of the extent of the slaughter. At the time, it was thought to have ranged from “many hundreds of thousands” to two million people dead.

It is also widely thought that the Allies quickly organized military tribunals in Nuremberg and Tokyo after the war, to rapidly bring to justice the couple-dozen German and Japanese officials believed to have borne the greatest responsibility for the most horrendous wartime crimes.

But well before the end of the fighting, nearly two years before the opening of the Nuremberg tribunal in November 1945, a UN commission on war crimes was at work in London, laying the groundwork for the eventual trials of more than 36,000 indicted war criminals. The trials were quietly conducted in national courtrooms across Europe and Asia — from Guam to Greece, Poland, France, the Philippines, Hong Kong and Yugoslavia — beginning in late 1945 and continued until well into the 1950s, years after the commission’s closed in March 1948.

While one might justifiably assume that the US and Britain were the unsung heroes of this dogged and ambitious pursuit of justice, the two countries were actually more responsible for the secrecy in which the commission’s work was conducted.

In fact, elements of the two governments were never enamored of the idea of the UN War Crimes Commission, and once it was established, they worked tirelessly to wrap up its work and shut it down as fast as possible. Their efforts succeeded in 1948, when thousands of pending war-crimes trials were dropped and the accused were freed from detention.

This effort came to pass after officials of the US State and War Departments concluded that with the war’s end, the commission’s work was undermining goals to rebuild and remilitarize Germany and confront Communism amid the new threat stemming from the emerging Cold War.

The officials also argued that such trials were an impermissible violation of national sovereignty. Allowing an international court to pursue “excesses” committed inside Germany amounted to inviting a non-American tribunal to “try those who were guilty of, or condoned, lynching in our own country,” US Secretary of War Henry Stimson argued in September 1944. While Stimson supported the international prosecution of crimes related to “aggressive war,” he dismissed the idea of “crimes against humanity,” a form of wrongdoing that had not yet become law.

The heroic yet unsung work of the 17-nation UN War Crimes Commission is revealed and explored in a new book by Dan Plesch, “Human Rights After Hitler: The Lost History of Prosecuting Axis War Crimes.” Plesch is an expert on international justice and director of the Center for International Studies and Diplomacy at SOAS University of London (formerly known as the School of Oriental and African Studies).

The commission, set up in October 1943 in London, worked as a sort of international grand jury, clearing cases to be passed on for judging by national courts of the various Allied nations. Some of the courts began gathering evidence and holding trials in London because the countries they represented were still occupied by the Axis powers. Before its demise, the commission generated more than 8,000 cases targeting more than 36,000 individuals and units. By 1947, it was providing legal advice and support as well as international legitimacy to more than 20 war-crimes courts organized by its 17 member-nations.

But after its shutdown, its archive was classified in 1949 at the insistence of US intelligence officials seeking to switch the focus of the international community from the threat of Nazism to the dangers of Communism. Although the commission objected, its files remained concealed from public view until Plesch’s intervention in 2011.

“Examination of the material is now beginning to revolutionize legal and political responses to international crimes,” Plesch boasts.

One of the archive’s most extraordinary secrets was solid evidence that the major powers knew a lot about the Holocaust’s atrocities nearly two years before previously thought, he writes.

“The commonly heard line of argument — that ‘we did not really know and this explains why we did not do more to help’ — becomes increasingly weak when it is clear that the Allied governments did know, did condemn, and did have sufficient legal footing and firsthand evidence to approve hundreds of criminal indictments, yet they still did not help the Jews.”

Another secret was the prominent role played by Washington in bringing the internationally fostered war-crimes trials system to a premature end. “The accepted story was that the commission’s ineffectiveness meant that it warranted little more than a footnote in any account documenting the development of international criminal justice,” Plesch writes.

Even Hitler had felt the commission’s sting, he notes. While Hitler was never indicted for trial at Nuremberg because he died in April 1945, months before the tribunal began operating, the UN War Crimes Commissions had privately determined in November 1944 that he could be held criminally responsible for the acts carried out by Germany in the countries it occupied.

“President Truman made anticommunism the priority over holding the Nazis to account for their crimes,” Plesch says. “Internally, his administration was determined to close down the UN War Crimes Commission as fast as possible and curtail trials in Germany. The commission’s files contain indictments against thousands of Nazis who were then allowed to go free.”

Despite its shutdown, the commission’s work lived on, later pursuing international crimes against humanity as an accepted legal norm, Plesch writes. Its legal work, he says, helped pave the way for a wave of crucial international arrangements, including the Universal Declaration of Human Rights, the Genocide Convention, the European Convention on Human Rights, the Third and Fourth Geneva Conventions and even the European Union and NATO.

“What is rarely if ever discussed is that the high-level negotiations on agreements for the future were taking place at a time when the Western powers were burying the Nazi past with great determination,” Plesch writes.

The commission’s ideas and its work are still valuable — even today — to the international community, Plesch argues.

“How fortunate we are to have the ideas and work of the thousands of people who fought for justice as part of the Allied victory in World War II,” he writes. “We must seize the opportunity to use their legacy. The suppression of the UN War Crimes Commission’s achievements and its work should embolden us to use it as a model to the full, energized by outrage at its long-enduring loss.”

“Human Rights After Hitler: The Lost History of Prosecuting Axis War Crimes,” by Dan Plesch; 978-1-62616-431-4

Irwin Arieff

Irwin Arieff is a veteran writer and editor with extensive experience writing about international diplomacy and food, cooking and restaurants. Before leaving daily journalism in 2007, he was a Reuters correspondent for 23 years, serving in senior posts in Washington, Paris and New York as well as at the United Nations (where he covered five of the 10 years that Sergey Lavrov spent in New York as Russia’s senior UN ambassador). Arieff also wrote restaurant reviews for The Washington Post and Washington City Paper in the 1980s and 1990s with his wife, Deborah Baldwin.