Oppenheimer first met Nelson at a Spanish war relief party in fall 1939, and the two men and their families had subsequently gone on social outings together. Nelson spent much of 1940 “on the shelf”—hiding out at a cabin in Redwood City under an assumed name, at a time when it appeared that the government was about to declare the Communist Party illegal. He had emerged shortly after America’s entry into the war to become chairman of the San Francisco branch of the Communist Party. He moved the party’s base of operations to a storefront office in Oakland when the big shipyards in the East Bay began recruiting new workers.111
What was said between Nelson and Oppenheimer in the meetings arranged by Folkoff remained outside the range of the bureau’s microphones. But Oppenheimer’s continuing involvement in progressive causes showed that he had decided to ignore Lawrence’s admonition against left-wandering.
Since the Schenectady meeting, however, Oppie had apparently begun rethinking his activist role. In mid-November, after failing to catch Lawrence before the latter left for a meeting in New York, Oppenheimer wrote a letter to him, apologizing for the blowup over the union and offering assurance that “there will be no further difficulties.”112
Still, it was soon evident that Oppie had not completely forsworn political causes. Three weeks later, on December 6, he attended a benefit for veterans of the Spanish war’s Abraham Lincoln Brigade. As late as April 1942, Oppenheimer was still giving $150 monthly to Folkoff.113
Acting on King’s recommendation, on January 26, 1942, the agent in charge of the San Francisco FBI office—N. J. L. “Nat” Pieper—asked bureau director J. Edgar Hoover for permission to extend COMRAP’s technical surveillance to Oppenheimer, Chevalier, and Addis. “This group of individuals is on such a plane that it is unlikely that any confidential Party informant now available to this office will be able to reach them and determine their actual position in the Party,” Pieper wrote Hoover.114
Ignorant of the S-1 Project and of Oppenheimer’s role in it, Hoover approved only the wiretap on Chevalier—which was subsequently denied by the attorney general. Pieper renewed his appeal to Hoover in March, citing further evidence from existing wiretaps that Addis remained an active party recruiter. On April 15, the FBI director turned down this request as well, chiding Pieper in the process for putting mention of the secret COMRAP program in writing.115
Just two weeks later, Oppenheimer filled out OSRD’s personnel security questionnaire, his first step in getting a clearance to work on the bomb project. Although Oppie, listing organizations to which he belonged, included the American Federation of Teachers and the left-wing American Association of Scientific Workers, there was no mention either of FAECT or of the “discussion group” that he and Chevalier had organized.*116
Lawrence’s was the first name that Oppie listed as a reference. While McMillan and Birge would also write glowing letters of recommendation to go in Oppenheimer’s file, Ernest’s was by far the strongest endorsement:
I have known Professor J. Robert Oppenheimer for fourteen years as a faculty colleague and close personal friend. I am glad to recommend him in highest terms as a man of great intellectual caliber and of fine character and personality. There can be no question of his integrity.117
* * *
Although Conant had grudgingly agreed to approve a temporary clearance for Oppenheimer, he had not ceased to worry about project security at Berkeley. In February 1942, Conant summoned John Lansdale, a newly promoted captain in the U.S. Army’s Military Intelligence Service, to OSRD headquarters. A Harvard law graduate, Lansdale before the war had defended the Cleveland Railway Company against personal injury suits resulting from trolley accidents. Since being recalled to active duty, he had been assigned to G-2’s Counter-Intelligence Group in Washington.118
Conant ordered Lansdale to Berkeley in civilian clothes to test security procedures at the Rad Lab. Lansdale was given a temporary membership card for the Faculty Club, obtained by Conant from Sproul, and a copy of a recent Stanford commencement speech by Lawrence describing the operation of the cyclotron.119
By chance, Lansdale encountered a Berkeley professor on the train en route to California who wrote him a letter of introduction to the dean of the law school, Max Radin.120 Max’s brother, Paul, was an anthropology professor on campus and a member of the political discussion group to which Oppenheimer and Chevalier belonged.
Renting a room at International House, Lansdale bought a notebook on Telegraph Avenue to serve as a diary and on Friday morning, February 20, strolled up Cyclotron Hill—through a pair of open gates posted with “No Visitors” signs, he noted—to the site of the unfinished 184-inch. After spending a leisurely two hours studying blueprints laid out on a bench and talking with the construction superintendent, Lansdale joined Max Radin for lunch at the Faculty Club. Radin pointed out Lawrence, who, he explained, was a frequent traveler to Washington on a government project seeking “an explosion from the sudden expansion of the atom.”
Later that afternoon, Lansdale returned to the 184-inch and was considering stealing some of the blueprints when he was noticed by Alvarez and asked to leave. During dinner at the Faculty Club, Lansdale brought up the subject of the cyclotron’s possible military use with Cooksey, who warily skirted the subject, speaking instead of the machine’s application to cancer research.121
Lansdale spent a total of two weeks in Berkeley getting to know many of those he identified in his diary as “Lawrence’s Brain Trust.” At breakfast one day, chemist Joseph Kennedy boasted that since a pound of U-235 contained enough energy to lift all the buildings in San Francisco half a mile into the air, whichever country separated enough uranium to make a bomb would win the war. But Kennedy told Lansdale that he doubted a way could be found to separate that much uranium before the fighting ended.
Lansdale returned to Washington in early March to brief Conant. (“Oh, dear … oh, dear,” the Harvard president
