These materials were transmitted by men working secretly for the Soviet Union and without the knowledge or permission of the British government. Later there would be more, and more valuable, information about the state of the British and American atomic-bomb programs, sent to Moscow by spies such as John Cairncross (the probable source of the data Kurchatov saw in early 1943), Klaus Fuchs, Theodore Hall, David Greenglass, and Julius Rosenberg. That these men, and others, provided important atomic intelligence to the Soviets is no longer in doubt: evidence gleaned from a US National Security Agency (NSA) top-secret codebreaking operation that ran for over three decades following the end of the Second World War, called ‘Venona’, shows that the Soviets had a number of spies in the United States, several of whom conveyed substantial knowledge of the Manhattan Project through handlers attached to the Soviet embassy or consulates. Venona, revealed fully only after the Cold War had ended in the mid-1990s, contained roughly 3,000 messages sent during the war by Soviet operatives to officials in Moscow. These messages were so highly classified that they were inadmissable as evidence in court cases pursued against accused spies during the early Cold War; successful convictions relied instead on less direct evidence from other sources, confessions, or the credibility to judges or juries of those making accusations of espionage.17
The discovery of Venona and the implication of Soviet spies more generally in the transmission of‘secrets’ from the West to the Soviet Union has contributed to a triumphalist conservative interpretation of the Cold War. Here is proofpositive, some historians have seemed to say, that the Russians were up to no good, that their own nuclear program was nothing without a supply of information from more advanced programs, that they stole and cheated their way to nuclear parity with the United States during the Cold War, as if confirming their general duplicitousness, untrustworthiness, and capacity for serious misbehavior. Each new disclosure about atomic spies, fully substantiated or not, was greeted with a kind of knowing sneer; driving spies out of history’s woodwork became an occasion for gleeful bashing of ‘revisionist’ historians who had dared to imagine more nuanced or numerous causes of the Cold War than Soviet perfidy alone. This tendency was abetted, though perhaps unwittingly, by the term used to describe the acquisition of nuclear weapons by more and more nations after 1945: proliferation. That is a biological, even botanical word, which means reproducing ‘by multiplying new parts’, as in budding. It suggests that the United States was the sole source of nuclear knowledge, of understanding how to develop a bomb, and that therefore anyone else who learned to do it must have discovered the Americans’ secret formula. There was a center and a periphery of nuclear knowledge. Since the Manhattan Project was secret, and since after 1945 the United States prohibited dissemination (another biological term—it means, first, ‘to scatter seed’) of information about the bomb’s construction, it must have been espionage that allowed the Russians to penetrate the American nuclear curtain and test a bomb in the late summer of 1949, many years before Groves, at least, thought such an occurrence possible.18
As Kurchatov’s excitement over the British material in March 1943 indicates, the Soviets did learn by espionage important information about nuclear physics and bomb building in the West. The Russians gave the codename ‘Enormoz’ to their ‘nuclear research’ project in the United States, Britain, and Canada. According to Pavel Sudoplatov, a general in the KGB and by his own account a Soviet ‘spymaster’ during the war, the Russians had twenty-nine agents inside the Manhattan Project. That is probably an exaggeration—and, even if there were that many, most were of negligible influence—but Enormoz plainly bore some attractive fruit. Quiet Klaus Fuchs, a communist driven from Germany by the Brownshirts, had found physics work alongside Rudolf Peierls at Birmingham; the two men began in earnest to work on the bomb in the spring of 1941. ‘When I learned the purpose of the work,’ Fuchs would say, ‘I decided to inform Russia’—a matter of ideological necessity and strategic duty, he thought. The Soviets, as noted, learned of the MAUD Report, engineering work at the great American plant at Oak Ridge, Tennessee (this courtesy of Fuchs), and evidently something of the composition of Enrico Fermi’s University of Chicago squash court reactor. Fuchs went to Los Alamos, part of the British scientific team there, in August 1944. Already in place was a precocious Harvard physics student named Theodore Hall. An expert on the properties of uranium, Hall had been assigned Room T-236. ‘Oh, that’s just next door to U-235,’ he quipped, but no one found it funny. Ted Hall thought the only way to ensure world peace over time was to make sure that the Russians knew what the Americans knew about atomic bombs. Also at Los Alamos, having arrived nine days before Fuchs, was David Greenglass. Not a physicist but a machinist, Greenglass was, along with his wife, Ruth, a member of the Young Communist League, though not of the Communist Party itself. He thought the Soviets were fighting a magnificent battle against Fascism and that Stalin and other Soviet leaders were ‘geniuses’ who used force against their own people only ‘with pain in their hearts’. Greenglass’s brother-in-law and recruiter was Julius Rosenberg, an inspection engineer for the Army Signal Corps and a Soviet agent since 1942.19
Through couriers and contacts, these men dispatched to Moscow a good deal of information about the atomic bomb. Fuchs and Hall, both well placed at Los Alamos, contributed material on the implosion core of the plutonium bomb. (None of the scientists underwent body searches when they left The Hill for time in town.) Fuchs provided, in early 1945, ‘a quite considerable packet of information’, according to his courier Harry Gold, which included an account ‘summarizing the whole problem of making an atomic bomb as he then saw it’. Hall offered much the same, telling his Soviet contact that ‘all the outstanding physicists of the US, England, Italy and Germany (immigrants), and Denmark are working on this thing’, and that he did not want to see the Soviet Union ‘blackmailed’ by some nuclear fraternity at the war’s end. David Greenglass gave Julius Rosenberg a list of Los Alamos scientists and several rough sketches of lens molds that would be used to make devices critical to the plutonium bomb’s implosion core. Rosenberg himself, excluded from life on The Hill but a true believer, gave his Soviet contact, Alexander Feklisov, a (non-nuclear) proximity fuse for Christmas in 1944. It was Julius’s most important gift to the Soviet Union—ironically, given his fate and his later reputation as an atomic-bomb spy.20
Some analysts have concluded that the information passed to the Soviets, especially by Fuchs, was critical to their ability to produce a plutonium-based bomb by August 1949. There is something oddly comforting in this belief, in the idea that Soviet knowledge came by proliferation: the American scientists are accorded a monopoly on perceptiveness, American officials a monopoly on problem solving, and only through underhanded means did the Russians (and ultimately others) gain the information they needed to make a bomb. Soviet intelligence officials, who have an interest in proving the importance of espionage, and some Soviet scientists, who do not, have claimed that they succeeded in building a bomb because ofsecrets stolen from the Manhattan Project. Kurchatov, who had found the British material of ‘inestimable significance’ in early 1943, two years later rated intelligence from Theodore Hall ‘of great interest’, then Fuchs’s 1945 report as having ‘great value’. (Fuchs provided more details of the plutonium bomb’s design in reports in June and September 1945.) Kurchatov later said that the first Soviet bomb, tested on 29 August 1949, was a replica of the one the Americans had dropped on Nagasaki, the design of which had been secured from Fuchs and others. The KGB officer Pavel Sudoplatov argued that the Soviets rejected all American attempts to limit atomic energy starting in late 1945 because they ‘had already stolen the information they needed from the United States to build their own bomb’. ‘The United States would later accuse the USSR of having stolen their atomic secrets,’ wrote Feklisov, the case officer for Fuchs and Julius Rosenberg. ‘This is true. I was in a position to know that Soviet nuclear weapons were very closely based on American prototypes,’ indeed that the first three Soviet test bombs were ‘replicas’ of American weapons.21
But there are several reasons to think that information purloined from the Americans was not, in itself, the critical factor explaining why the Soviets got the bomb when they did. In the first place, intelligence gained by espionage had to be crosschecked for accuracy. Stalin and Lavrenti Beria, the fearsome KGB chief whom Stalin put in charge of the Russian nuclear-bomb program in August 1945 (‘dealing with Beria was no joke’, recalled Yuli Khariton), worried that their intelligence was incomplete, or subject to disinformation by the Americans, whom they suspected were on to them. (There is a Soviet myth that, at one point, Kurchatov brought Stalin a plutonium sphere, coated with nickel, to reassure the dictator that the physicists knew what they were doing. ‘And how do we know that this is plutonium, not a sparkling piece of iron?’ Stalin allegedly asked.) Second, while Fuchs provided sound and specific data on the design of a plutonium bomb, he was not asked to describe the workings ofa plutonium-producing reactor, including how to ‘can’ the uranium (as at Hanford) or how to prepare graphite for use as a moderator. Either the Soviets did not know enough to ask Fuchs about these processes, or their scientists already knew what was needed to make them work. And Americans like Groves underestimated the ability of the Soviet Union’s centralized economy to gear up quickly for the production of nuclear weapons. What had been for the Americans an extraordinary wartime effort to mobilize production facilities, knowledge, and resources was for the Soviets, after August 1945, a matter of Stalin readjusting his economy’s priorities with a virtual stroke of the pen.22
Above all, the claim that the Soviet bomb succeeded primarily because of information passed by spies ignores substantial evidence that the Russians had deep nuclear knowledge and a sophisticated research program of their own, both before and during the war. Despite the decision taken to depri-oritize nuclear-weapons work during the war and the dislocation suffered by Ioffe and his physicists, Soviet scientists had not suspended their thinking about nuclear power and atomic weapons. Peter Kapitsa, mired in a liquid oxygen project and believing in any case that no bomb was in prospect any time soon, nevertheless suggested to a group of scientists in October 1941 that an atomic bomb, capable of destroying ‘a major capital city with several million inhabitants’, was theoretically possible. Popular science magazines carried reasonably accurate stories about the Soviet ‘discovery’ of fission and ongoing nuclear work in well-appointed labs. Russian physicists, who had before the war read and replicated the experiments of their counterparts elsewhere, and who had made discoveries of their own, did not forget what they had learned while the war raged. Stalin’s ‘hedged’ bomb project started in 1943. Khariton, Zeldovich, and others never abandoned work on explosives; engineers dedicated themselves to projects of a scale commensurate with what would be needed to create a bomb. As Holloway points out, the Soviets managed to test, in 1951, a gun-assembly uranium core bomb, for which Fuchs had provided no help. What did help, and despite more Soviet suspicion ofAmerican disinformation, was publication, just weeks after the atomic bombings, of an official US report called Atomic Energy for Military Purposes, usually called the Smyth Report after its author, Princeton physicist Henry D. Smyth. As they had with their agents’ reports from the United States, Soviet authorities read the Smyth Report ‘with great interest’.23
What most determined the timing of the first Soviet bomb test in 1949 was not information learned from spies but, Holloway concludes, the availability of uranium in the Soviet Union. ‘As soon as uranium became available in sufficient quantity,’ he writes, ‘Kurchatov was able to build and start up the experimental reactor.’ Fuchs, who had not visited the Soviet Union, thought that he had accelerated the Soviet bomb project ‘by one year at least’; Holloway is willing to make this one to two years’ time saved through intelligence information, and notes that the British, who were far better represented at Los Alamos than the Soviets, took five years from deciding to build a bomb to testing it, about a year longer than the Russians. ‘One should not overestimate the importance of [the] Soviet intelligence community in setting up the atomic program although its efforts and its contribution were commendable,’ wrote Khariton, who was there. Emphasis on the role of espionage in the Soviet project exaggerates the extent to which proliferation explains the extension of nuclear knowhow. A better model is polycentric, acknowledging as it does multiple sources of knowledge and multiple sites of imaginative and productive work on the nucleus. Physicists in the Soviet Union can share the credit and must share the blame for their efforts to build an atomic bomb after 1945.24