For those ready to devote a whole season to absorbing Oppenheimer entire, an excellent introduction can be found in another of the new books now appearing; Jeremy Bernstein’s short profile, Oppenheimer: Portrait of an Enigma, will prepare the reader for the story in its long form. Bernstein was a student at the Institute for Advanced Study (IAS) in Princeton in the late 1950s when Oppenheimer was its director and took away a vivid impression of the man. A lively writer as well as a physicist, Bernstein has written many articles for The New Yorker and a number of books about scientists, and he not only understands but is actually interested in the physics that brought the bomb into the world. Indeed, his short book has the clearest feel for Oppenheimer’s way of doing science; it goes beyond the names of problems and papers to explain in brisk fashion the questions he was thinking about, and how he made such a profound impression on the leading physicists of the period before the war.
Best are several telling anecdotes of Bernstein’s encounters with Oppenheimer in the years closely following his public humiliation by the AEC. He notes, for example, that Oppenheimer always sat in the front row at Institute for Advanced Study physics seminars and often made sharp or biting comments about things said or questions asked. “If he made what he thought was a witty comment,” Bernstein writes, “he would look around to make sure that we had all taken it in.” Reading that we better understand the impulse behind Oppenheimer’s question to Joseph Volpe, the AEC’s lawyer, after a hearing in which Oppenheimer made cruel fun of Strauss for opposing export of American radioactive isotopes, a position Oppenheimer dismissed as silly: “My own rating of the importance of isotopes in this broad sense,” he said, “is that they are far less important than electronic devices, but far more important than, let us say, vitamins, somewhere in between.” “Well, Joe, how did I do?” Oppenheimer asked, expecting praise for the way he had skewered Strauss. “Too well, Robert,” Volpe answered, “much too well.” He had seen the look on Strauss’s face, and so had two other AEC members, Gordon Dean and the chairman of the AEC, David Lilienthal. “I remember clearly the terrible look on Lewis’ face,” said Dean. Lilienthal called it “a look of hatred …that you don’t see very often in a man’s face.”
This gratuitous offense was given in June 1949, when Oppenheimer was still a national hero and probably had more influence on American atomic policy than any other single person. He was chairman of the AEC’s General Advisory Committee (GAC) but his power was of the moral, not the bureaucratic, variety. Military officers, and especially the “big bomb” men of the Air Force, egged on by Edward Teller, found him a formidable adversary. As early as March 1950, McMillan writes, Teller sought out Borden, then a staffer on Congress’s Joint Committee on Atomic Energy (JCAE), to suggest that slow going on the hydrogen bomb was Oppenheimer’s fault for discouraging younger men from working on the problem. A few months later Teller planted another seed with Borden. Oppenheimer, he said, had been quite a leftist in his day; his brother Frank never would have joined the Communist Party without Robert’s approval; it was Robert who brought Frank to Los Alamos to work on the atomic bomb; and as chairman of the GAC, with a Q clearance that allowed him to know everything, Oppenheimer was well placed to be the most damaging spy in American history—that is, if he were a spy.
This speculation came only a few months after the confession of the Soviet spy Klaus Fuchs, prominent at Los Alamos and the man who kept the notes during an early conference on “the super”—the hydrogen bomb—in 1946. In the realm of malevolent insinuation Teller’s sly suggestion ranks as a grandmaster chess opening, and it was more than Borden could handle. By November he was telling the chairman of the JCAE, “I conclude that we may well have another Fuchs still in the project today….”
But personal animosity alone does not explain the destruction of Oppenheimer. Just as important was the argument over building a hydrogen bomb. The decision rested with the president but the man with the most powerful public voice in arguing whether it was to be yes or no was Oppenheimer. On this question he was of two minds between the end of the war and the moment in October 1949 when the GAC, prompted by the discovery that Russia had successfully tested its own atomic bomb, had to take a stand. Central to Oppenheimer’s thinking was the bomb itself—not just the practical difficulties of making it “better,” but also the troubling implications of the huge increase in destructive power promised by fusion weapons, a thousand times greater than the fission bombs which had destroyed Hiroshima and Nagasaki.
The practical difficulties, always safer to stress than moral hesitations, were formidable. The inventive Teller had many ideas for using fission bombs to create the high temperatures required to ignite fusion but none of the ideas worked—a fact Teller blamed on three people: on Oppenheimer for discouraging the project; on Norris Bradbury, the new director of Los Alamos, for not giving the program a crash priority; and above all on the Polish mathematician Stanislaw Ulam, for demonstrating time and time again that Teller’s math was wrong since the hydrogen would cool down too quickly for a working bomb. Never once, then or in the decades before his death in 2003, did Teller concede that while he was the one insisting the problem had to be solved, he did not know how to do it.
The years of intellectual combat that preceded a solution for the ignition problem are brilliantly told by McMillan, who explains the science, evokes the contrasting styles and gifts of Ulam and Teller, and brings fully to life the strangely distant time when men were learning how to unleash the energy of stars, but still had to do their calculations with slide rules and the primitive early computers that John von Neumann was building at the IAS in Princeton. One of Ulam’s inspired discoveries was a kind of shorthand method for calculating the progress of an exploding bomb, a gimmick that saved months of laborious number-crunching by hand. From Teller’s point of view the news from Ulam was always bad—rapid cooling, no ignition or no propagation of fusion throughout the hydrogen fuel, ever larger estimates of the amount of tritium needed to help trigger ignition. Tritium was expensive in the usual way of money, but in another way as well—every gram of it tied up production capacity that could have been used to make about eighty grams of plutonium, the fissionable material principally used in fission bombs.
Teller’s wartime design for the so-called “classical super” called for about four hundred grams of tritium; by 1947 he conceded that the requirement had doubled to eight hundred grams at a “cost” of sixty-four kilograms of plutonium, enough for perhaps between four and six fission bombs. The bad news did not halt there. In the fall of 1950 a new tritium estimate suggested a need for between three and five kilograms. Now the “cost” was four hundred kilograms of plutonium, getting on toward enough for fifty bombs. Teller’s bright ideas never caught up with the ignition problem, but despite these repeated failures Oppenheimer and the GAC supported and funded research on fusion weapons, albeit without enthusiasm, arguing what seemed self-evident—a larger number of smaller bombs would provide a lot more military clout than a smaller number of larger bombs, which in any event were too big for any targets except the largest cities.
When the GAC with Oppenheimer as chairman met at the end of October 1949 to consider whether an all-out “crash” program for the H-bomb was a sensible response to the Russian success, Teller’s difficulties offered a ready excuse for delay. But after two days of discussion, as McMillan describes in detail, the GAC raised a very different objection to H-bombs—they were immoral. Eight of the nine members of the GAC—Glen Seaborg was absent and could not participate—opposed a crash program, saying, “We all hope that by one means or another the development of these weapons can be avoided.” More remarkably, all agreed that the power of hydrogen bombs made them essentially weapons of genocide. Two of the members, Enrico Fermi and I.I. Rabi, went still further in a separate opinion, putting into words conclusions their colleagues probably shared, at least in part, but were unwilling to state baldly. “It is clear that the use of such a weapon cannot be justified on any ethical ground,” they wrote.
The fact that no limit exists to the destructiveness of this weapon makes its very existence and the knowledge of its construction a danger to humanity as a whole. It is necessarily an evil thing considered in any light.
Oppenheimer did not write this strong version of the case against the H-bomb, but Teller, Strauss, and the Air Force “big bomb” generals all assumed that it was his doing. They were not far from right. Since Hiroshima and Nagasaki Oppenheimer had changed. He soon developed second thoughts about the use of the bomb on Japan when it was already “essentially defeated,” and he was disturbed and probably a little shocked by the cavalier way in which an early effort to halt the spread of the bomb—the “Acheson-Lilienthal plan,” actually written by Oppenheimer with the help of the faithful Rabi—was handed over to a self-important financier, Bernard Baruch, by President Truman. Baruch reshaped the plan as a poisoned apple and the Russians predictably turned it down.
But Oppenheimer did not simply disagree with the drift of official policy; his moral qualms cut closer to the bone. There was no hiding from the horror of the destruction at Hiroshima and Nagasaki. Philip Morrison and Robert Serber had both been part of a survey team which had walked the ground, seen the victims, and returned to describe the devastation.
It should not seem odd that a weapon which killed a hundred thousand people in a day, most of them women and children, would raise troubling thoughts in the minds of the people who had worked flat out for two years to build it. When I first started to talk to Los Alamos scientists about the invention of nuclear weapons twenty years ago I assumed that they had long since confronted and sorted out the rights and wrongs of the case, but I soon found that it wasn’t so. At an early date their thinking had frozen around a handful of simple ideas—building the bomb was justified because the Germans were trying to do it; using the bomb was justified because it ended the war and demonstrated to the world their terrible destructive power; building more and better bombs was justified because they served as a deterrent and made it more difficult to use them again. Perhaps this self-reassurance should not surprise us; it is hard to condemn something that you have irretrievably done.