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Bruno Pontecorvo around the time of his defection to the USSR

“I want to die as a great scientist, not as your fucked spy.” These words were spoken in Russian by Bruno Pontecorvo a year before his death in 1993, in reply to a Russian government official who was trying to arrange for a visiting historian to interview him. They come as close as Pontecorvo ever came to confirming the widespread belief that he had been spying for the Soviet Union when he was working at the Canadian nuclear reactor project in the 1940s.

The words vash jebanyi shpion describe the way he did not wish to be remembered. In Half-Life, his new biography of Pontecorvo, the particle physicist Frank Close translates them as “your fucking spy,” which misses the precise meaning. Pontecorvo was certainly aware of the precise meaning of the word when he used it. It describes his emotional reaction to the way he was treated by the Russians as well as by the Western media. It gives us a glimpse of the inner turmoil that he successfully concealed from his family and friends. He was undoubtedly a great scientist. Whether he was a spy is still open to question.

The following facts are not open to question. Pontecorvo was a brilliant young experimental physicist working with Enrico Fermi in Rome in the years 1934–1936. He helped Fermi to start a revolution in nuclear physics using slow neutrons as an experimental tool. The use of slow neutrons made it possible for the first time to produce nuclear transformations involving atoms of all kinds. One of the reactions that slow neutrons produced was the fission of uranium, a discovery that Fermi missed.

In 1936, when Mussolini joined Hitler in persecuting Jews, Pontecorvo, who was from a nonobservant Jewish family, moved to France and worked there with the husband-and-wife team Irène Curie and Frédéric Joliot. Curie and Joliot were prominent and passionate Communists. Pontecorvo joined the Communist Party and remained an apparently sincere believer in communism for the rest of his life. In 1940, when Hitler overran France, he escaped to the US and found a job with the Texas oil company Well Surveys, introducing the technology of neutron logging to the American oil industry. His experimental skills were precisely what were needed to find oil-bearing rock surrounding a drilled borehole.

In 1943 Pontecorvo was invited to join the Canadian nuclear reactor project at Chalk River. He worked there on reactors for six years. His work had nothing to do with bombs but was then classified as secret. In 1949 he moved to the British nuclear energy project at Harwell and continued to do secret work on reactors.

In the summer of 1950 he traveled with his wife Marianne and their three small sons for a holiday in Italy. After some weeks of apparently carefree hiking and swimming, they suddenly flew from Rome to Helsinki and were met there by Russian cars that took them to Russia. They disappeared without a trace for five years. The British police who searched their house were astonished to find Marianne’s fur coat left in the wardrobe. She had evidently not planned to spend the next winter in Russia.

After five years, Pontecorvo emerged as an honored and active member of the Soviet physics research institute at Dubna. In the same year, 1955, all the countries with nuclear energy projects agreed to abolish secrecy of information about reactors. After that, only information about bombs remained secret. Pontecorvo said many times that he never worked on bombs, either in Canada or Britain or Russia. But he remained in the USSR, not allowed to travel to Western countries, for twenty-eight years. After 1978 he was allowed to travel but kept his home in Dubna.

Frank Close tells this story as a human drama, leaving the central mystery unsolved. Why did Pontecorvo make the sudden decision to uproot his family and take them to Russia? The move was an unmitigated disaster for Marianne. She had suffered from recurrent depression in France and in Canada. In Russia her depression became worse, and she spent a large part of her life in psychiatric hospitals. She could never rise to the challenge of creating a meaningful life for herself in Russia. Bruno did far better. He took care of the boys, took care of Marianne to the best of his ability, made friends with his Russian colleagues, and pursued his professional career as a physicist at Dubna.

But for him too, the move to Russia was a disaster. He was an experimenter, and needed world-class apparatus to do world-class experiments. Several times, he had ideas for experiments that might have produced major discoveries if he had been free to use the newest apparatus in Western Europe or the US. Doing experiments with the apparatus available at Dubna, he could not be competitive. He was well aware that the move to Russia had ruined his chances of becoming a world leader in physics like his teacher Fermi.


Close compares the situation of Pontecorvo in 1950 with the situation of two physicists who were actual spies, Allan Nunn May and Ted Hall. If Pontecorvo had not flown to Russia, there might have been three possible outcomes. In the worst and least likely case, if he had actually been a spy and confessed, he would have been sentenced like Nunn May to about seven years in a British jail, with Marianne and the boys going to live with her family in Sweden. After emerging from jail he could have resumed his professional life at least as successfully as Nunn May.

In the most likely case, if he had been a spy but the authorities had no publicly useable evidence against him, he could have denied the charges and continued his life as a person under suspicion but never prosecuted, like Ted Hall. In the third case, if he had never been a spy, he would be a free citizen with nothing to fear. All three alternatives would have been in many ways preferable to his life as an isolated exile in Russia.

The only serious problem that Pontecorvo had with the British authorities in 1950 was the fact that he was considered to be a security risk because of his Communist past. This meant that he could not be permanently employed at Harwell. John Cockcroft, the director of Harwell, had already discussed this problem with Pontecorvo. Cockcroft had arranged for him to be transferred to a position as professor at the University of Liverpool where he would have no access to secrets, and he had agreed to the transfer. Liverpool was then a good place for an experimental particle physicist, with a big new particle accelerator under construction.

It is easy to imagine Pontecorvo adapting quickly to life in Liverpool, with its strong local culture of music halls and rock bands. He was an impulsive entertainer and partygoer, loving the limelight, always the life and soul of a party. We can imagine, ten years later, when the Beatles made Liverpool a world center of pop culture, Pontecorvo becoming the first Beatles fan and helping them in their rise to fame and fortune. Even if he had not become a Beatles fan, he could look forward to a promising future as an experimenter in Liverpool.

Close offers his own conjectural solution of the mystery of Pontecorvo’s hasty flight to Russia. Suppose that he had really been a spy, but that he had told his Soviet contact in 1950 that he would be moving from Harwell to Liverpool and would no longer be able to provide any secret information. It is possible that the authorities in Moscow regarded this as an act of betrayal to be severely punished. When he was in Italy in the summer of 1950, a Russian agent might have informed him that he must decide immediately between two alternatives. Either he must fly to Russia or the Russians would make sure that the British government would have legal proof of his criminal activities.

This theory, that Pontecorvo flew to Russia because he was blackmailed by his Russian contacts, would also explain the fact that the Soviet authorities kept him incommunicado for five years after his arrival in Russia and never really trusted him. Close concludes his story with the remark that the USSR may have punished Pontecorvo more severely for his act of betrayal than the United Kingdom punished Nunn May. Nunn May sat in prison for seven years, Pontecorvo for forty-three.

I met Pontecorvo at an international meeting of physicists at Dubna in 1956. This was the first chance for most of the foreign visitors to see Russia and learn about Russian nuclear projects that had been secret until 1955. Pontecorvo was wearing elegant white trousers and a white sweater, as if he had just stopped by on his way to a game of tennis. He said nothing about his work. It seemed as if his appearance at the meeting was choreographed to give us an impression of relaxed well-being without any opportunity for real communication. The Dubna laboratories were still under construction, and we could see gangs of gulag prisoners working outside when we looked out of the windows. Communication with Pontecorvo or with the construction workers was equally impossible.

Close tells the story of Pontecorvo’s life in sharp detail, with all of the facts and conjectures carefully documented. He has two main sources of information. He interviewed many of Pontecorvo’s friends and relatives, including especially his oldest son Gil, who stayed close to his father and still lives in Dubna today. He examined the voluminous reports about Pontecorvo that are now accessible in the archives of the intelligence services of Britain, Canada, the United States, and Russia. The intelligence records never give any clear evidence that Pontecorvo was a spy, but they give abundant evidence that he was a person of serious concern to all four countries. He may not have been a spy, but he was certainly spied upon by many others.


What do we learn from spy stories like this one? If Pontecorvo was a spy, the main effect of his spying was to advance the building of a nuclear reactor in the Soviet Union by a few years. The Canadian reactor may have provided some information that was useful for Soviet bomb designers, but the overall effect of Pontecorvo’s information could not have been militarily important. With or without Pontecorvo, the Soviet Union had enough competent bomb designers to produce all the bombs that it needed. Other technical spies, Klaus Fuchs and Ted Hall, were inside Los Alamos and gave up-to-date information about bomb designs to their Soviet contacts. But this information too had only a minor effect on the history of Soviet weapons development. Perhaps the spies accelerated the production of the first Soviet bombs by two or three years, but those bombs soon became obsolete and were superseded by new designs invented without the help of spies.



Bruno Pontecorvo arriving in Rome with his KGB minders, 1978

Technical spies were unimportant because the Soviet Union had plenty of first-rate scientists working in the relevant areas of nuclear physics. In 1939, immediately after the discovery of fission, the first paper describing in detail the possibilities for nuclear power reactors was published in the open Soviet literature by Yakov Zeldovich and Yulii Khariton. Fifteen years later, Khariton was director of the Soviet bomb laboratory at Sarov, and Zeldovich was a member of his team of brilliant theoreticians, working with Andrei Sakharov to design hydrogen bombs.

If a country has this kind of home-grown technical talent, it does not need technical spies to make progress. If a country does not have this kind of talent, technical spies will not be an effective substitute. In either case, the contribution of technical spies will be marginal. Science is a collective enterprise, and needs a community of active participants to succeed in any large venture.

The public vastly overrates the importance of technical spies such as Klaus Fuchs, because the same word “spy” is used for technical spies and for tactical spies. The archetype of the tactical spy is Judas Iscariot, the secret enemy betraying his master and directly causing his master’s death. For two thousand years, the story of Judas has been linked with the image of a spy in the cultures of Europe. Another tactical spy, not quite as notorious as Judas, was Kim Philby, a British intelligence officer who held high positions in the British diplomatic service. He gave his Soviet contacts lists of names of undercover agents operating in various countries, so that Soviet authorities could quickly eliminate them. He was directly responsible for many disappearances. Tactical spies are rightly condemned by public opinion and by the traditional rules of war. They have immediate effects on the life and death of fellow citizens. They are fair game for any soldier to kill, with or without a legal trial. But technical spies are different. Technical spies are more concerned with things than with people.

Another spy story illustrates the general truth that technical spies do not do much harm. When I first came to America as a graduate student at Cornell University in the fall of 1947, I got to know two young families who were building homes side by side in Ithaca. In those days of postwar scarcity, the wartime ethic of helping neighbors and sharing resources still prevailed. The graduate students helped to build houses for the young professors. I have a vivid memory of the joyful winter day when we pulled on the ropes with all our strength and hauled the two rooftrees into place. The fathers were Alfred Sarant, a junior professor of engineering, and Bruce Dayton, a junior professor of physics. Each had a wife and two young children. In the spring of 1948 we celebrated with them when they moved into their new homes. They left in our minds a lasting image of American friendliness and competence.

One morning two years later, Alfred Sarant’s wife woke up and found her children still asleep and her husband missing. The same morning, Bruce Dayton found his children still asleep and his wife missing. Alfred and Carol had disappeared from the face of the earth. Cornell University was in an uproar, and the whole country joined in the search for the missing pair. No trace of them was found. I heard nothing more of them for sixty-two years.

Then in 2013 I met in California a Russian lady who is married to a Russian mathematician. They had emigrated some years earlier from Russia to the US.

After a few minutes of conversation, I was able to tell the Russian lady that I had known her parents. She is a daughter of the missing pair. She told me that her father had a distinguished career in Russia as a leading designer of computers. Unlike Pontecorvo, he changed his name to Filipp Staros and was able to pass in Soviet society as a Russian. Filipp and Carol raised four Russian children.

When Filipp died in 1979, the official Soviet newspaper Izvestiya published a glowing obituary, celebrating his achievements and his services to the Soviet people, and not mentioning his foreign ancestry or his undercover activities. So Staros achieved what was denied to Pontecorvo, being acclaimed by his adopted country as a great scientist and not as a chewed-up spy. Twelve years later, when the Soviet Union disintegrated, Carol returned to the US and was reunited with her original husband. When I spoke with her Russian daughter, Carol and Bruce were still alive, enjoying a peaceful old age in California. So their story had a happy ending.

The beginning of their story was not so happy. Sarant was in fact a Soviet spy, working in a ring organized by Julius Rosenberg and including another engineering colleague, Joel Barr. The ring operated successfully for several years during and after World War II, while the three spies were engaged in various kinds of secret work. Then Rosenberg was arrested and executed, and Barr and Sarant—along with Carol, who had not been a spy—escaped to Russia. Joel Barr became Iosif Berg.

Staros and Berg lived openly with their Russian names, and their past history as spies was forgotten. A Communist society gave them some of the opportunities that they and Rosenberg had dreamed of when they were idealistic left-wing students at the City College of New York and Cooper Union in the 1930s. With the help of Nikita Khrushchev, who was then trying to modernize the Soviet Union, Staros and Berg built a high-tech city with the name Zelenograd, intended to be the Soviet equivalent of Silicon Valley. Zelenograd flourished under their leadership and became a center of electronic and computer industries.*

It is difficult to weigh the good that they did in providing modern electronic technology to Russia against the evil that they did to the United States by spying. I do not pretend to be unbiased in my judgment. Having known Alfred and Carol personally, I find that the good greatly outweighs the evil in their lives. My meeting with their daughter only confirms this conclusion.

Why then does the American public still consider all spies to be demons? Why does the public make no distinction between technical spies like Julius Rosenberg stealing useful knowledge and tactical spies like Kim Philby destroying human lives? Perhaps it is because the American public is misled by the American secrecy system. The secrecy system is a bureaucratic monster that classifies vast quantities of information as secret, making it impossible for the ordinary citizen to see the difference between important and unimportant secrets.

I have observed the secrecy system from the inside for many years and I faithfully obey its rules. But I consider it profoundly harmful to national security as well as to public morality. It is habitually abused to protect ineffective weapons and tactical mistakes from public scrutiny. And it is abused to protect illegal and unconstitutional activities such as ill-treatment of prisoners and domestic spying.

Of the millions of official documents that are stamped “Secret” every year, perhaps 1 or 2 percent contain real secrets. A real secret is one that would cause real danger if our enemies got hold of it. The rest of the so-called secrets are mostly the result of bureaucratic caution. The system rewards caution, because the penalties for revealing secrets are severe, but there are no penalties for putting “Secret” stamps on harmless pieces of paper. Among the millions of harmless pieces of paper are many that are stamped “Secret” because they contain information that could be politically embarrassing to the government.

A radical reform of the secrecy system is long overdue. Real secrets should be rigorously protected, as they are in the existing system. The rest should be thrown open, accepting the risk that some of them will be dangerous. The dangers of disclosure of unimportant secrets are outweighed by the advantages of openness. The reduction of the volume of secrets will reduce the number of people who require security clearances. Fewer secrets will mean fewer clearances and fewer spies inside the security fences.

Outside the security fences, a more open society means more public awareness and more participation of citizens in deciding questions of war and peace. Our spy stories are teaching us the same lesson as our strategic mistakes in Vietnam and Afghanistan and Iraq. Secrecy in the making of important decisions is the greater evil, and spies are comparatively harmless. Spies may cause us to lose a battle, but secrecy protecting political decisions from scrutiny may cause us to lose a war.