The State Department Panel of Consultants on Disarmament, sometimes referred to as the Oppenheimer Panel, was a group created by the United States Department of State that existed from April 1952 to January 1953, during the last year of the Truman administration. It was composed of prominent figures from science, law, education, and the government, and chaired by physicist J. Robert Oppenheimer. Its purpose was to make recommendations regarding U.S. disarmament policy in the context of the Cold War.

The panel's initial recommendation represented a last attempt to forestall the advent of thermonuclear weapons by urging the U.S. government to not undertake a first test of the hydrogen bomb.Bernstein, "Crossing the Rubicon", p. 133. This recommendation was not followed and the test went ahead as planned in the fall of 1952. The panel subsequently made a series of recommendations regarding U.S. policy towards nuclear weapons and relations with the Soviet Union. One recommendation, advocating that the U.S. government practice less secrecy and more openness towards the American people about the realities of the nuclear balance and the dangers of nuclear warfare, attracted the interest of the new Eisenhower administration and led to that administration's Operation Candor and Atoms for Peace initiatives during 1953.

Background Following the first atomic bomb test by the Soviet Union in August 1949, there was an intense debate within the U.S. government, military, and scientific communities regarding whether to proceed with development of the far more powerful hydrogen bomb, a debate that was decided on January 31, 1950, when President Harry S. Truman gave the order to go ahead with the new weapon.Young and Schilling, Super Bomb, pp. 1, 62–65. At the time, creation of a thermonuclear device was by no means assured, since initial ideas for how to create one had proved unfruitful. However, beginning with the Teller–Ulam design breakthrough in March 1951, there was steady progress and by 1952 there were additional resources devoted to staging, and political pressure towards seeing, an actual test of a hydrogen bomb.Bernstein, "Crossing the Rubicon", pp. 137–139.

Although defeated in January 1950, the opponents of the hydrogen bomb did not give up, instead continuing to fight a battle against the new weapon in different forms, and on different fronts, over the next several years.Young and Schilling, Super Bomb, pp. 2, 151.

The panel The creation of the Panel of Consultants on Disarmament was announced by the State Department on April 28, 1952. The panel was commissioned by Secretary of State Dean Acheson and its purpose was to advise the State Department and other federal agencies regarding U.S. disarmament policy and the U.S. role within the United Nations Disarmament Commission.Chernus, "Operation Candor", p. 781. In particular, the panel members met with officials from the State Department, the U.S. Department of Defense, the Atomic Energy Commission (AEC), as well as with U.S. representatives to the UN commission."Oppenheimer and Bush Appointed to New Advisory Group on Disarmament", p. 133.

The five members of the panel, and their organizational affiliations at the time of its establishment, were: J. Robert Oppenheimer, Director, Institute for Advanced Study Vannevar Bush, Carnegie Institution of Washington John Sloan Dickey, President of Dartmouth College Allen Dulles, Deputy Director of the Central Intelligence Agency Joseph E. Johnson, Carnegie Endowment for International Peace

The two most prominent members were Oppenheimer, a physicist who as head of the Los Alamos Laboratory had been a key figure in the Manhattan Project that created the U.S. atomic bomb, and Bush, an electrical engineer who as director of the Office of Scientific Research and Development had played a pivotal role in persuading the United States government to initiate said project. Both had been members of the group behind the Acheson–Lilienthal Report of 1946, an early proposal for international control of atomic weapons. Oppenheimer had chaired the General Advisory Committee to the AEC, which had issued a report opposing development of the hydrogen bomb, while Bush had remained always influential in nuclear policy discussions.Young and Schilling, Super Bomb, pp. 41, 45–48, 92. Dickey and Johnson were both former State Department officials, and both had become believers in efforts towards international cooperation. Oppenheimer was selected as chair of the panel, and its executive secretary was McGeorge Bundy, at the time an associate professor of government at Harvard University.Bernstein, "Crossing the Rubicon", pp. 140–141.

An article in the Bulletin of the Atomic Scientists said that the creation of the panel was "encouraging news, indicating at least some realization of the urgency of the general disarmament problem," but added that it was hoped the panel could focus on the nuclear weapons aspect of the problem.Inglis, "The New Working Paper and U.S. Atomic Policy", p. 134.

Report on timing of a thermonuclear test At the panel's second meeting, in May 1952, the members agreed to form a proposal that the first test of a thermonuclear weapon be postponed.Young and Schilling, Super Bomb, p. 92. That test, known as Ivy Mike, had been scheduled well in advance,Rhodes, Dark Sun, p. 487. and was set to take place on November 1, 1952, on Enewetak Atoll in the Pacific (October 31, Washington time).Hewlett and Duncan, Atomic Shield, pp. 590–591. This would be just a few days before the November 4 holding of the United States presidential election, 1952, was to take place, in which Truman was not running for re-election.Rhodes, Dark Sun, p. 497.

Bush brought the test postponement idea to Acheson verbally, saying it was improper to, just before an election, conduct a test which would leave an incoming administration in a more dangerous world that they had had no say in bringing about. Bush also argued that conducting a test would forestall the best chance of preventing that more dangerous world; instead, he and the panel favored the idea of a mutual test ban, on the grounds that it could be verified without intrusive inspections, as both nations had the ability to detect violations through atmospheric testing and other unilateral means.Bernstein, "Crossing the Rubicon", pp. 141–142.

Meanwhile, with Bush and Oppenheimer as the leaders of the effort, the panel worked on a written report which would further explain its thinking.Bernstein, "Crossing the Rubicon", p. 143n31. The panel argued that a successful U.S. test would only encourage the Soviets to intensify their efforts towards an H-bomb, both out of an urgent need to match the American achievement and because a successful test would prove that a thermonuclear device was technically possible.Holloway, Stalin and the Bomb, p. 311. In propaganda terms, conducting a test would be to the disadvantage of the United States, since it would appear to be the country marching towards nuclear war. Militarily, the advent of hydrogen bombs on both sides could prove to be an overall negative for the United States, since the United States and its Western European allies had more targets within their territory that were suitable for attack by the hydrogen bomb than the Soviet Union and its Eastern European allies did, and the Soviets could more effectively use their smaller amount of fissionable materials in H-bombs than they could in A-bombs. Most importantly, a conducted H-bomb test would represent a point of no return; whereas a test ban or delay would give everyone a chance to step back and think about whether they really wanted the world to go where it was headed (and since the United States had a big enough lead in A-bombs, it could afford to take that chance).

The main argument against the panel's proposal was made to Acheson by Paul Nitze, the Director of Policy Planning in the State Department and a lead architect of the NSC 68 blueprint for the Cold War.Bernstein, "Crossing the Rubicon", p. 142. Nitze's logic was that if a test ban was to the advantage of the United States, the Soviets would use the ban to make up time in their weapons development work and then violate it by testing themselves.Young and Schilling, Super Bomb, pp. 92–93. Nitze further argued that the ability to do effective unilateral monitoring of a test ban might not always exist, and that if an inspection regime became necessary, the Soviets would never accept it.Young and Schilling, Super Bomb, p. 93. Finally Nitze thought that American development of the H-bomb ahead of the Soviets, combined with the existing American lead in A-bombs, might intimidate the Soviets into accepting a disarmament agreement.

Another reason the panel gave for not conducting a U.S. test of a thermonuclear weapon was that such a test would produce radioactive debris, the capture and analysis of which would give Soviet scientists clues about the nature of the U.S. design and thus help them in their own efforts to develop a weapon.Holloway, Stalin and the Bomb, pp. 311–312. Scholars have disagreed on whether in fact the Soviets did gain any useful information from the Ivy Mike test when it occurred, but on balance it seems that Soviet detection and analysis equipment was insufficient to the task.Young and Schilling, Super Bomb, pp. 85, 180n85.

The panel had little chance of any of their pleas succeeding in Washington, where they were almost completely lacking in political allies: some of those who had opposed the H-bomb in 1949 had since left positions of influence, while many others had changed their views and now supported it.Bernstein, "Crossing the Rubicon", pp. 145–148. The panel's formal report, "The Timing of the Thermonuclear Test", was submitted around early September 1952.Bernstein, "Crossing the Rubicon", p. 143. It gained few adherents, and at a meeting of the National Security Council in October 1952, the panel's suggestions were quickly dismissed by Acheson and Secretary of Defense Robert A. Lovett – with Lovett even suggesting that papers on the proposal should be destroyed.Bernstein, "Crossing the Rubicon", pp. 148–149. President Truman never saw the panel's request for a test ban or delay, but if he had, there is little doubt he too would have rejected it.Bernstein, "Crossing the Rubicon", p. 151.

There was a separate desire voiced for a very short delay, perhaps of two weeks, in the test, for reasons related to the test date being just before the presidential election date. Truman wanted to keep the thermonuclear test away from partisan politics but had no desire to order a postponement of it himself; however he did make it known that he would be fine if it was delayed past the election due to "technical reasons" being found.Hewlett and Duncan, Atomic Shield, p. 591. AEC commissioner Eugene M. Zuckert was sent to Enewetak to see if such a reason could be found, but weather considerations indicated it should go ahead as planned; and so Ivy Mike did, on the date intended.Rhodes, Dark Sun, pp. 497–498. A few days later, in a secret meeting at Augusta National Golf Club, President-elect Dwight D. Eisenhower was briefed on what had taken place; the report forwarded to him from the AEC stated in simple fashion that "The island ... which was used for the [test] ... is missing".Hewlett and Holl, Atoms for Peace and War, pp. 1, 3.

Report on armaments and U.S. foreign policy On around January 9, 1953, the panel submitted to Acheson the main focus of its work, a final report titled "Armaments and American Policy".