Oppenheimer’s decision to entertain this macabre alternative to the bomb was arguably simple prudence, a hedge against the unpredictable. Two years earlier, Compton’s review panel had given radiological warfare precedence, ahead of the fission bomb, among the possible military applications of atomic energy. The figures that Teller cited in his lecture came from a December 1941 report by Princeton physicists Smyth and Wigner, who had likened the use of radiation as a weapon to “a particularly vicious form of poison gas.” Wigner found the subject so distasteful that he subsequently tried to disassociate himself from the report.20
But eighteen months of war had changed the old way of thinking.21 Fermi had already broached the subject of radiological weapons with Oppenheimer and was surprised at the reaction. Oppie wrote Fermi, in reply, of plans to poison “food sufficient to kill a half a million men, since there is no doubt that the actual number affected will … be much smaller than this.”22
Visiting from Chicago that spring, Fermi found Oppenheimer’s callous bravado indicative of a different mood among the scientists. He was surprised to discover, Fermi told Oppie, that his friends at Los Alamos now sounded like they actually wanted the bomb to work.23
* * *
By spring 1943, the Manhattan Project was also a priority of the Soviet Union’s. Two years earlier, the NKVD—the People’s Commissariat of Internal Affairs—had ordered its intelligence officers serving under diplomatic cover in Soviet embassies and consulates to begin collecting information on the status of technical research in the West. The NKVD’s spies were supplemented by a parallel espionage network run by the Soviet army’s Intelligence Directorate, the GRU.
Thirty-five-year-old Pavel Fitin, head of the NKVD’s First Directorate (Foreign Intelligence), had been instructed to focus his efforts upon answering some technical questions of particular interest.24 One of these concerned American progress toward a fission weapon. In preparations to steal U.S. secrets, Fitin had given his enterprise a code name appropriate to the Manhattan Project: Enormous (Enormoz).25 The cryptonyms that Fitin assigned to vital intelligence targets within the United States were borrowed from history. But they also reflected an ideological slant and, in some cases, a sense of humor: Washington, D.C., was Carthage; New York City was Tyre; San Francisco became Babylon.26
Nearly a generation’s experience of running spies in the United States had given the Soviets a base of operations that was both broad and deep. In the capital alone, the Russians had two active espionage rings stealing secrets from the U.S. government. The larger ring, headed by a Berkeley-trained economist, Nathan Gregory Silvermaster (code name Robert), had twenty-seven members working in six different federal agencies.27 The spies in Robert’s ring included the assistant secretary of the treasury, Harry Dexter White (Richard), and Lauchlin Currie (Page), a senior aide to President Roosevelt.28 Others recruited by the Soviets to spy included a congressman from New York (Crook), the daughter of the U.S. ambassador to prewar Berlin (Liza), and at least three State Department officials (Ernst, Frank, and Ales.)29
With the outbreak of war, American intelligence, too, became a target of particular interest to Fitin. The Office of Strategic Services (Cabin) was compromised from its mid-1942 birth by more than a dozen agents, who reported on its activities to Moscow; as was the Office of War Information (Wireless), which split off from the OSS that same year.30 Not surprisingly, also of special interest to the Soviets were the U.S. government agencies responsible for spy hunting, the FBI (Shack) and army G-2 (Salt).31
To pass stolen secrets to Russia, Fitin established a residentura, a base for espionage operations, at the four-story townhouse on East Sixty-first Street that served as the Soviets’ New York consulate. He put an NKVD agent with a background in engineering—Leonid Kvasnikov, code-named Anton—in charge of spying on the bomb.32
Like agents at other Soviet diplomatic posts, Kvasnikov used Amtorg, the Soviet Union’s import-export agency, as a cover for espionage activities. As the clearinghouse for the wartime Lend-Lease program, Amtorg had offices in major cities on both coasts. Soviet couriers sent purloined documents by diplomatic pouch on Russian-bound ships, as well as via a special air connection operating from an Army Air Corps field in Great Falls, Montana.33
Shorter messages were encrypted and sent between Moscow and the Soviets’ diplomatic posts by regular commercial telegraphy.*34 When the volume of cable traffic, including secrets, threatened to become overwhelming, the Soviets clandestinely installed illegal short-wave radio transmitters at their consulates in New York and San Francisco.35
But since research on a fission weapon had its true origins in England, it was through the NKVD’s British spies, rather than Fitin’s American network, that Moscow Center first learned about the bomb.36
On the same day in July 1941 that British scientists completed the M.A.U.D. report, the NKVD rezident in London, Anatoli Gorski (Vadim), had informed Moscow of its contents.37 The reliability of Vadim’s information was confirmed by another spy, code-named Rest.
Rest was Klaus Fuchs, a German-born physicist and Communist who had fled to England in 1933. By 1941, Fuchs was working with M.A.U.D. Committee physicist Rudolf Peierls on gaseous diffusion and bomb physics at Birmingham University.38 Shortly after Germany’s invasion of Russia, Fuchs had begun passing information on British atomic research to Moscow through the Soviets’ military attaché in London.39
With the enemy at the gates, the Russians did not react to the news from Gorski and Fuchs until March 1942, when Lavrentii Beria, head of the NKVD, informed Stalin and the State
