---
title: "J. Robert Oppenheimer"
chunk: 10/17
source: "https://en.wikipedia.org/wiki/J._Robert_Oppenheimer"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:07:13.473219+00:00"
instance: "kb-cron"
---

As a member of the Board of Consultants to a committee appointed by Truman, Oppenheimer strongly influenced the 1946 Acheson–Lilienthal Report. In this report, the committee advocated the creation of an international Atomic Development Authority, which would own all fissionable material and the means of its production, such as mines and laboratories, and atomic power plants where it could be used for peaceful energy production. Bernard Baruch was appointed to translate this report into a proposal to the United Nations, resulting in the Baruch Plan of 1946. The Baruch Plan introduced many additional provisions regarding enforcement, in particular requiring inspection of the Soviet Union's uranium resources. It was seen as an attempt to maintain the United States' nuclear monopoly and rejected by the Soviets. With this, it became clear to Oppenheimer that an arms race was unavoidable, due to the mutual suspicion of the United States and the Soviet Union, which even Oppenheimer was starting to distrust.
After the Atomic Energy Commission (AEC) came into being in 1947 as a civilian agency in control of nuclear research and weapons issues, Oppenheimer was appointed as the chairman of its General Advisory Committee (GAC). From this position, he advised on a number of nuclear-related issues, including project funding, laboratory construction and even international policy—though the GAC's advice was not always heeded. As chairman of the GAC, Oppenheimer lobbied vigorously for international arms control and funding for basic science, and attempted to influence policy away from a heated arms race.
The first atomic bomb test by the Soviet Union in August 1949 came earlier than Americans expected, and over the next several months, there was an intense debate within the U.S. government, military, and scientific communities over whether to proceed with the development of the far more powerful, nuclear fusion–based hydrogen bomb, then known as "the Super". Oppenheimer had been aware of the possibility of a thermonuclear weapon since the days of the Manhattan Project and had allocated a limited amount of theoretical research work toward the possibility at the time, but nothing more than that, given the pressing need to develop a fission weapon. Immediately following the end of the war, Oppenheimer argued against continuing work on the Super at that time, due to both lack of need and the enormous human casualties that would result from its use.
Now in October 1949, Oppenheimer and the GAC recommended against the development of the Super. He and the other GAC members were motivated partly by ethical concerns, feeling that such a weapon could only be strategically used, resulting in millions of deaths: "Its use therefore carries much further than the atomic bomb itself the policy of exterminating civilian populations." They also had practical qualms, as there was no workable design for a hydrogen bomb at the time. Regarding the possibility of the Soviet Union developing a thermonuclear weapon, the GAC felt that the United States could have an adequate stockpile of atomic weapons to retaliate against any thermonuclear attack. In that connection, Oppenheimer and the others were concerned about the opportunity costs that would be incurred if nuclear reactors were diverted from materials needed for atom bomb production to the materials such as tritium needed for a thermonuclear weapon.
A majority of the AEC subsequently endorsed the GAC recommendation, and Oppenheimer thought that the fight against the Super would triumph, but proponents of the weapon lobbied the White House vigorously. On January 31, 1950, Truman, who was predisposed to proceed with the development of the weapon anyway, made the formal decision to do so. Oppenheimer and other GAC opponents of the project, especially James B. Conant, felt disheartened and considered resigning from the committee. They stayed on, though their views on the hydrogen bomb were well known.
In 1951, Teller and mathematician Stanislaw Ulam developed the Teller–Ulam design for a hydrogen bomb. This new design seemed technically feasible and Oppenheimer officially acceded to the weapon's development, while still looking for ways in which its testing or deployment or use could be questioned. As he later recalled:

The program we had in 1949 was a tortured thing that you could well argue did not make a great deal of technical sense. It was therefore possible to argue also that you did not want it even if you could have it. The program in 1951 was technically so sweet that you could not argue about that. The issues became purely the military, the political and the humane problem of what you were going to do about it once you had it.
Oppenheimer, Conant, and Lee DuBridge, another member who had opposed the H-bomb decision, left the GAC when their terms expired in August 1952. Truman had declined to reappoint them, as he wanted new voices on the committee who were more in support of H-bomb development. In addition, various opponents of Oppenheimer had communicated to Truman their desire that Oppenheimer leave the committee.

=== Panels and study groups ===