Jeremy Bernstein is a physicist and gifted writer who has succeeded admirably in making the history and sociology of science understandable to laymen. His profiles of scientists appeared in the New Yorker for nearly 30 years and his book on Albert Einstein gained a wide audience. Until now, Bernstein never wrote at length about J. Robert Oppenheimer (or "Julius Robert Oppenheimer," as J. Edgar Hoover preferred), who conducted the orchestra of brilliant physicists, chemists and others to develop the atomic bomb during World War II. Bernstein's admiration is transparent: Oppenheimer's "ability in physics" and his "astounding charisma" enabled him to accomplish what probably none other might have done. But Oppenheimer: Portrait of an Enigma is tempered with criticism of the physicist's naivete and his arrogance, which contributed to his tragic public humiliation in 1954 when the government withdrew his security clearance.

Bernstein's engaging and revealing profile is a reminder of the events that so colored and charged Oppenheimer's life but, in the longer run of history, pale when measured against his signature achievements.

At his 1954 hearing, Oppenheimer stated that he had been largely apolitical until the mid-1930s. But his growing concern with the fate of Jews in Germany (for him a rare conscious identification with things Jewish) and the effects of the Depression led him into a flurry of political activity. His new friends included Jean Tatlock, a colleague's daughter who was deeply involved in Communist Party affairs, and his future wife, Kathryn "Kitty" Puening, also a party member and then married to one of Oppenheimer's colleagues. Oppenheimer involved himself in union activities and various anti-fascist and pro-communist causes, but Bernstein flatly rejects any idea that he was a Communist Party member.

Before he was tapped for the Manhattan Project, Oppenheimer taught advanced physics at UC Berkeley and Caltech. He was highly regarded as a scientist but hardly known outside academic circles. In 1942, the War Department selected then-Col. Leslie Groves to head the top-secret project. Groves knew nothing about physics and needed a scientist coordinator. Oppenheimer seemed an unlikely choice. He was a theoretical, not an experimental, physicist; he read poetry in several languages; and he had a good deal of left-wing baggage. Bernstein speculates that Oppenheimer's apparent modesty about his work appealed to Groves, who later described the physicist as strictly his subordinate. He acknowledged his dependence on Oppenheimer's scientific advice but kept him compartmentalized from the whole project.

Despite Groves's self-promoting description of himself as the man in charge, Oppenheimer's role is universally conceded to have been indispensable. He had the respect, admiration and affection of the Los Alamos scientists; clearly it was he who marshaled the disparate personnel that shaped America's nuclear future, according to scientists who worked with him.

Oppenheimer worried the higher-ups who were charged with maintaining secrecy and security. The record of his left-wing political attachments was available from the start. Groves's aides Maj. K.D. Nichols and William L. Borden, with assists from Army intelligence and the FBI, made them an issue, but Groves was unimpressed. He had seen FBI reports and knew of Oppenheimer's political involvements, as well as those of his brother, wife and girlfriend. But Groves deemed him "absolutely essential to the project" and insisted on security clearance "without delay, irrespective of the information which you have concerning Mr. Oppenheimer."

At the same time, Oppenheimer encountered a more dangerous adversary in the gifted physicist Edward Teller. Oppenheimer named Hans Bethe to head the theoretical division, a slight the Hungarian-born Teller never forgot. Bethe's efforts to involve Teller in the primary atom bomb work proved futile. Bernstein believes that Oppenheimer had abandoned any hope for Teller to be a productive group member, leaving him to work mostly alone on a hydrogen, or "super" fusion bomb. Teller continued that work and pursued his theories after the war. Only the discoveries made by the Polish-born mathematician Stanislaw Ulam in 1951 and the work of others finally made the hydrogen bomb possible.

The Atomic Energy Commission's General Advisory Committee, which consisted of Oppenheimer and a roster of distinguished scientists, unanimously recommended against a crash program to accelerate development of the super bomb. Oppenheimer's "lack of enthusiasm" was shared by a group that hardly could be surpassed for its expertise. Its 1949 report centered on two points: First, the then-circulating proposals for an H-bomb were based on Teller's yet-unrealized ambitions; second, the H-bomb's potential for far greater destruction than the atomic bomb alarmed committee members, who feared it would become a weapon of genocide.

Bernstein remembers that Oppenheimer once suggested that potential Cold War targets in the Soviet Union and elsewhere were "too small" for a hydrogen weapon. Atomic weapons would have been as effective. "[I]f the hydrogen bomb had never been invented," Bernstein writes, "the nuclear stockpile would have been about the same." But military and scientific enthusiasm for bigger and bolder weaponry proved irresistible. The Soviets had exploded their first atomic device just two months before the committee's report. U.S. scientists' pervasive contempt for Soviet science meant, of course, that they could not have developed it themselves. The United States must have been betrayed from within, and an already-burgeoning fear of subversion broadened into wholesale inquiries of patriotism and loyalty. Oppenheimer became the most famous casualty.

The AEC moved to suspend Oppenheimer's clearance in the spring of 1954. Chairman Lewis Strauss, a longtime adversary and previously an isolated voice on the commission, led the effort, motivated by his personal animus toward the physicist and their fundamental disagreement over weapons development. Strauss handpicked a three-judge panel to conduct a "trial" that in many ways parodied the infamous Soviet purge trials fifteen years earlier. Oppenheimer was only publicly humiliated, not executed. The presiding judge consistently ruled in favor of the government. Oppenheimer's prosecutor had complete access to classified documents, which were denied to Oppenheimer's lawyer.

Why bother to suspend his clearance? Oppenheimer had not been active in weapons development; he was then head of the Institute for Advanced Study at Princeton. His clearance had been scheduled to expire in June 1953, but was extended for another year. With Oppenheimer's allies gone, Strauss, a former investment banker who would later become Eisenhower's commerce secretary, had to rush the proceedings because Oppenheimer would not be subject to AEC jurisdiction after June 30, 1954.

The hearing resurrected Oppenheimer's political involvements and associations of two decades earlier. Particular attention centered on the "Chevalier incident," involving Haakon Chevalier, a UC Berkeley French professor and Communist Party member. Chevalier relayed information in 1943 to Oppenheimer from a friend with contacts to a Soviet spy ring in San Francisco that Soviet scientists were eager to share information with their U.S. counterparts. Oppenheimer failed to report the encounter promptly to security forces, then hesitated before revealing names. Bernstein believes the best that can be said is that Oppenheimer, torn by divided loyalties, made the worst choice. At his hearing, Oppenheimer called himself an "idiot" for his involvement, delighting prosecutors, who were eager to have him as an accomplice to his humiliation.

Panel members had no interest in Borden's charges that Oppenheimer was a spy. After all, what could they do, try him for treason? Espionage? The security charges were old stuff and the irony was that Oppenheimer still was being used by the government as an advisor, notwithstanding the allegations.

Oppenheimer's "lack of enthusiasm" for building more or bigger weapons simply meant that the government had no further use for him. And his enemies were formidable. An Air Force general testified that he believed Oppenheimer loyal but misguided. The Air Force wanted him removed; after all, Oppenheimer had dismissed its pet project for a nuclear-powered aircraft.

Bernstein focuses on the high drama of the conflict between Oppenheimer and Teller. Certainly Teller gave important testimony, affirming Oppenheimer's loyalty while questioning his commitment to further development of nuclear weapons. Teller alone was not decisive; he was not yet the commanding figure of later years. But he did provide legitimacy for the political, military and scientific forces (and Strauss) that demanded accelerated weapons development. Oppenheimer's dubious political past merely nourished prevailing demands for conformity.

Two judges concluded that Oppenheimer's security clearance was not in the country's interests. They said that Oppenheimer's "continuing conduct and associations" showed a dangerous disregard for national security; more to the point, his conduct in the hydrogen bomb debate was "sufficiently disturbing as to raise a doubt to whether his future participation & would be clearly consistent with the best interests of security." The third, Northwestern University chemist Ward V. Evans, dissented, bluntly concluding that "[t]o deny him clearance now for what he was cleared for in 1947, when we must know he is less of a security risk now than he was then, seems hardly the procedure to be adopted in a free country." The Institute for Advanced Study remained free to follow its own course. Oppenheimer offered his resignation, but the trustees unanimously expressed complete confidence in him. Institute trustee Strauss was absent.

In April 1963, the atomic commission announced that Oppenheimer had been selected for the Fermi Prize, which provided a $50,000 stipend. Teller had been the previous winner and, following custom, it was he who recommended Oppenheimer's selection. Bernstein is at a loss for an explanation; perhaps for Teller it was a means of repairing his relations with fellow physicists, many of whom supported Oppenheimer at the time of the hearing. President Kennedy's office announced on Nov. 22, the same day he was assassinated, that he would present the prize. President Johnson decided to go ahead with the ceremony, despite potential criticism from Oppenheimer's critics. Accepting the award, Oppenheimer told Johnson: "I think it is just possible, Mr. President, that it has taken some charity and some courage for you to make this award today. That would seem a good augury for all our futures." Oppenheimer and Teller shook hands; doing the right thing cost Johnson nothing. The trial belonged to a distant past.

Time and events have eroded the circumstances of Oppenheimer's fall from official grace. Communism is largely a relic of the past, and the Soviet Union is no more; we preoccupy ourselves now with political correctness as ideological attachments have declined. Oppenheimer's formal accusers are mostly forgotten. Nobel laureate Bethe, the sole surviving senior scientist at Los Alamos, has said that Oppenheimer "did a job & that perhaps no one else could have done." Oppenheimer and his incredible team transformed the world of science -- and more. Now, with his enemies on the sidelines of history, J. Robert Oppenheimer's reputation is secure, and his monumental achievement endures.