An Interview with Nancy Thorndike Greenspan

  • By Steve Case
  • June 30, 2020

The biographer discusses WWII, the Manhattan Project, and the complex legacy of a British traitor.

An Interview with Nancy Thorndike Greenspan









In addition to co-authoring four books with her late husband, child psychiatrist Stanley Greenspan, former health economist Nancy Thorndike Greenspan has also penned two biographies, including, most recently, Atomic Spy: The Dark Lives of Klaus Fuchs. This latest work, which came out last month, paints a complicated picture of a complicated man, and it makes for a riveting read.

Who was Klaus Fuchs?

Klaus Fuchs was a German, a naturalized British citizen, a brilliant physicist, a Nazi resistor, a communist, and a spy. Between every descriptor is a web of complexity and seeming contradiction. He risked extreme torture and death by the Gestapo to fight the Nazis in 1932-33. He handed the plans for the plutonium bomb to the Russians in 1945. He valued Britain and his friends, confessing his spying activities to save them from suspicion, and yet he betrayed them. His close friends stood by him. Who he was and why he spied have been mysteries. I found new information that dispelled misdirected assumptions and MI5’s half-truths.

What attracted your interest in writing Fuchs’ biography?

Previously, I wrote a biography of Nobel Laureate Max Born, The End of the Certain World: The Life and Science of Max Born. My first introduction to Fuchs was as Born’s post-doctoral assistant at the University of Edinburgh. Born’s letters portrayed Fuchs as brilliant scientist and worthy person. This kindly image intrigued me because I knew that he had spied. How did the pieces fit together? At that time, I combed through the British National Archives and found only a few folders on him. One contained a note requesting guidance on his 100 MI5 files. The answer: Throw them out. Someone didn’t listen. In 2003, documents began to flood from MI5, British counterintelligence, to the National Archives, and from these came clues to other corners of his life.

What were the most interesting aspects of your research?

Klaus Fuchs betrayed Britain, his adopted country. He took an oath of loyalty and he intentionally broke it. He lied to his country, to his friends, to his colleagues. He was a man molded by his roots and the cataclysmic events of history that still bedevil the mind. When his path as a serious student of mathematics crossed these perils, he took life-threatening risks and made grave choices. Reaching a deeper understanding of who he was, what he did, why he did it, and how he was caught allowed me to reflect on what this extraordinary life — a cautionary tale about morality and the prisms through which we perceive it — means today. 

What were your favorite research areas?

The historical background — some unknown to me — enthralled me. Correspondence at the University of Kiel archives detailing Fuchs’ fight with Nazi students, including their attempt to kill him, documents the Nazis’ rise to power through the lives of students. The diaries and oral histories of young refugees in British internment camps leave little doubt as to their harsh life. It was in internment that Fuchs publicly renewed his communist activities and formed a close friendship with a Russian agent. It had a decisive effect on his life.

Fuchs, even though then a German citizen, worked on the atomic-bomb project at Los Alamos, New Mexico, and gave away important secrets to Stalin’s government in Moscow. How could American security have been lax enough to permit this?

When Britain sent a few dozen of its best scientists to work on the Manhattan Project in 1943-44, it reassured the Americans that each of them had undergone a thorough vetting. The Americans did no checking. Many of the scientists had files with MI5 because they were German refugees. In Fuchs’ case, MI5 knew he had communist ties during his youth. It decided that his scientific value overcame the possibility, considered slight, that he would spy. Even so, it stressed to the British administrators of the program to keep Fuchs’ background from the Americans. Russia had its own brilliant scientists who were working on a bomb. Fuchs’ spying advanced their success by one to two years. 

During World War II, Germany and the USSR were bitter enemies. Why did Fuchs, a German, give secrets to the Russians?

It hinged from his early life in Germany. Fuchs’ father was a liberal Lutheran minister, an anomaly in that very conservative church. He was an outspoken socialist (though not a communist), and his advocacy of the working class strongly influenced Fuchs and his siblings. When the German socialists did little to fight the Nazis, Fuchs joined the communist students who, early on, risked their lives to stop the Nazis. Fuchs worked on the bomb because he hated the Nazis, but he spied to create a balance of power between Russia and the U.S. When he began spying in 1941, he characterized the British attitude as watching the Germans and Russians fight each other to the death with some preference for the Germans winning out. There was truth behind his perception.

Fuchs’ spying went undiscovered until several years after the war. How did they catch him?

During the war, the British and Americans intercepted coded messages from Russian agents to Moscow Central. They were useless because the KGB used unbreakable, one-time code pads. In the late 1940s, the Americans discovered that the Russians had duplicated some of these pads and deciphered some messages. They held hints of spying in the Manhattan Project, and MI5 identified Fuchs as the likely person.

What was your assessment of his personality and character? Was he inherently sinister? A dupe for clever spy-handlers? Something else?

Fuchs’ values derived from his commitment to a society based on equality, especially for the working class. He saw his steps as necessary to gain that society. To him, communism was the answer. When he heard of atrocities in Russia, he dismissed them as imperialist propaganda. He knew that with nuclear inequality, Russia was at the mercy of the U.S. Ultimately, he did see Stalin’s communism as a grotesque aberration of the ideal.

The Americans executed Julius and Ethel Rosenberg for having spied for the USSR. Was Fuchs executed by the British?

When Fuchs confessed in 1950, he assumed he would hang for treason [in Britain]. He learned differently just before his trial, when his lawyer explained that he was to be tried for espionage. Espionage, illegal under the British Official Secrets Act, carries a maximum sentence of 14 years imprisonment. The judge gave Fuchs the maximum, and Fuchs was stunned. Government prosecutors had convinced him that his cooperation would lighten the sentence. Even so, he continued to answer questions from MI5, as well as the FBI. Released in 1959 because of good behavior, Fuchs returned to East Germany. The British wished him to stay and do research. But in 1951, it had taken away his citizenship, ignoring his pleas. He never forgave them.

[Photo by Gary Grieg.]

Steve Case is a member of the Independent’s board of directors.

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