From AEC commissioner Sumner Pike, Oppenheimer received a letter proposing questions that the General Advisory Committee might address at the meeting scheduled for the coming weekend in Washington. Broadly, asked Pike, was the commission doing things that might be slowed or stopped, and were there other things that ought to be done in addition or instead, “to serve the paramount objective of the common defense and security?” Pike asked specifically about civil defense, further production expansion, radiological warfare and “any new aspects of the international control of atomic energy which may be perceived as a result of the new situation,” but he was most concerned about the Super, which he noted “would conflict” with fission weapons “in terms of demand for neutrons.” (The commissioners had heard, a few days earlier, that by 1951, given present production rates, there would be only enough tritium available in the US program for the one D + T booster shot scheduled for
Teller had rushed back to Los Alamos because Carl Hinshaw and two other members of the JCAE subcommittee would arrive there on Thursday for a briefing. Bradbury led the briefing, describing a possible Super design to the congressmen that would weigh twenty thousand pounds and yield at least one megaton — one million tons of TNT equivalent, more than seventy times as powerful as the bomb that destroyed Hiroshima. Bradbury thought such a weapon could be ready by 1958, nine years hence, although a test might be possible by 1952. Evidently Bradbury was assuming, optimistically, that MANIAC calculations of the main Super problem would determine that a Super was feasible in the first place.
After Robert Serber returned from Japan at the end of the war, he had left Los Alamos and moved to Berkeley to become director of theoretical physics at the Radiation Laboratory. In that position, in 1949, he had witnessed Ernest Lawrence's agitation after the announcement of the Soviet test. “I warned him about Edward's Super,” Serber recalls, “that it wasn't a practical idea at the moment. I told him if you want to really find out, you should talk to Bethe, but he never did. He was all gung-ho for the Super and he immediately — action was always the thing with Ernest — immediately asked what he could do and the thing to do was to build these reactors to make tritium.” Now Lawrence delegated Serber, Oppenheimer's old friend, to make the case in Washington to the GAC. “Why was I representing Ernest and Luis [Alvarez]? The reason Ernest asked me was he thought I would get a more sympathetic hearing from Oppenheimer than Luis would. Lawrence was a dictator and if he asked you to do something you either did it or you got fired. But that wasn't the principal reason. It didn't seem like a bad idea to build some more reactors. To make neutrons which could be used to make tritium or to make plutonium or whatever. It seemed to me like a plausible thing to do at that point.” But Alvarez also traveled east at the same time to lobby the GAC and the AEC commissioners informally, stopping in Chicago to discuss reactor design with Argonne Laboratory director and reactor pioneer Walter Zinn.
Serber arrived in Princeton on Thursday, October 27, to talk to Oppenhei-mer and to spend the night before the GAC meeting, which was scheduled to begin informally the following afternoon. By Thursday, Oppenheimer may have heard from Conant in response to his October 21 letter. Serber remembers Oppenheimer telling him about Conant's position and possibly showing him a letter. Conant, it seemed, had moved to a moral position against the Super in addition to raising technical and strategic questions. “I was astonished,” Serber recalls. “Coming from Berkeley, I had no idea that people were thinking anything except pushing weapons development as fast as they could. Conant was the prime mover in that opposition.” Serber's sense is that Oppenheimer was reporting to him what Conant intended to propose to the GAC, not that Oppenheimer himself had signed on to Conant's position.
Friday, October 28, Oppenheimer and Serber rode down to Washington together by train. George Kennan was scheduled to open the informal Friday afternoon session. Bell Telephone Laboratories president Oliver Buckley, Caltech president Lee DuBridge, Fermi, Rabi and Cyril Smith were able to attend. Manley served as secretary. Glenn Seaborg was in Sweden. In early September, Swedish Nobel laureate physicist Manne Siegbahn had invited the co- discoverer of plutonium to lecture during October in the country of his ancestors. “Well,” Seaborg says with a grin, “I knew what they meant. They wanted to look me over for the Nobel. I wasn't about to miss that, so I went. But I wrote Oppenheimer a letter.” In his letter, dated October 14, Seaborg deliberately softened his endorsement of an accelerated Super program. “Although I deplore the prospects of our country putting a tremendous effort into this,” he wrote, “I must confess that I have been unable to come to the conclusion that we should not… I would have to hear some good arguments before I could take on sufficient courage to recommend not going toward such a program.” Cyril Smith remembered vividly that Oppenheimer showed Seaborg's letter to the GAC members before the meeting opened Saturday morning.
Kennan talked, says Smith, “of the general state of industry in the USSR and the attitude of the Russian government vis-a-vis America.” The director of the State Department's Policy Planning Staff left Smith at least with the impression that it might be possible to negotiate a halt to the arms race with the Soviet Union. Kennan spoke for forty-five minutes; for the next hour the committee members discussed the issues. Next they heard Bethe, Smith recalls, “on the general state of thermonuclear research and on the probability that a working bomb could be built.” Bethe stressed the many technical problems that remained to be solved; Smith remembers being “freshly and strongly influenced by what he… said.” Bethe also found occasion in the course of the afternoon to talk to some of the committee members about the dark vision Weisskopf had conjured of thermonuclear war and the sense both men shared that such a war would destroy what it was supposed to preserve.
Serber rounded out the afternoon with a presentation on Lawrence's plan to build a heavy-water reactor under Radiation Laboratory sponsorship, carefully disassociating himself from the all-out Super crusade. “Fermi said to me, ‘Why Berkeley?’” he remembers. “‘It's the one place that has no experience at all building reactors.’ I said I think the point is that Ernest is trying to stress what he considers the importance of building more reactors, to the point where he's even willing to build them himself, and if there's a better way of doing it, Ernest will be the first one to applaud it.”
Conant was on hand when the GAC convened formally on Saturday morning, October 29, 1949. So was respected senior GAC member Hartley Rowe, one of the pioneering engineers who had built the Panama Canal. Downstairs in the lobby of the AEC building, Alvarez stationed himself by the door and watched people come and go. Oppenheimer formally — “very solemnly,” says Rabi — opened the meeting by posing the question whether to recommend a major program to build the Super — “not whether we should make a thermonuclear weapon,” Rabi interprets, “but whether there should be a crash program.” Next, DuBridge testified, Oppenheimer “asked the members of the committee if they would in turn around the table express their views on the question.” Oppenheimer was careful not to lead the committee members, but in DuBridge's recollection they had already made up their minds in any case:
Dr. Oppenheimer did not express his point of view… until after all the rest of the members of the committee had expressed themselves. It was clear, however, as the individual members did express their opinions as we went around the table, that while there were differing points of view, different reasons, different methods of thinking, different methods of approach to the problem, that each member came essentially to the same conclusion, namely, there were better things the United States could do at that time than to embark upon this super program… I suppose each person took five to ten minutes or thereabouts to express his views. After they were all on the table, the chairman said he also shared the views of the committee. We then discussed the question of how to state our views and our recommendations most effectively to the Commission. It was on this subject of how our general conclusions could be most effectively and clearly stated that a very substantial discussion went forward for the next day or two.
Not everyone would recall having made up his mind before the meeting began. Rabi had not; “there were some people,” he would testify, “and I myself was of that opinion for a time, who thought that the concentration on the crash program… was the answer to the Russian [atomic]… weapon.” Oppenheimer himself had not made up his mind before the meeting, he testified under oath in 1954; his views changed “in the course of our discussion.” They changed in the direction of Conant's views, an interviewer paraphrased Oppenheimer in 1957, as “a result of
