Szilard's petition against immediate use of the atomic bomb on Japan

Leo Szilard’s petition against immediate use of the atomic bomb on Japan was a wartime appeal to Harry S. Truman to make the surrender terms public before using the weapon. Its circulation drew substantial support among Manhattan Project scientists, but J. Robert Oppenheimer resisted accelerating its delivery to Washington. The petition arrived too late, leaving a consequential dispute over scientific responsibility and civilian authority without a timely place in the decision.

The petition and its demand

Two weeks after J. Robert Oppenheimer wrote his June 16 memorandum summarizing the science panel’s views, Edward Teller brought him a copy of a petition circulating at Manhattan Project facilities. Drafted by Leo Szilard, it urged the president not to use atomic weapons against Japan unless the terms to be imposed had first been made public and Japan, knowing those terms, had refused to surrender. The appeal did not simply object to the weapon’s use in the abstract: it made prior disclosure of the surrender terms a condition for using it.

The petition gathered 155 signatures over the following weeks. A counter-petition collected only two. A separate Army poll of 150 project scientists on July 12 found that 72 percent favored demonstrating the bomb’s power rather than using it militarily without prior warning. The poll and petition were distinct measures, but together they show that opposition to an unannounced attack was not confined to Szilard or a small circle of associates.

Oppenheimer’s opposition to circulation

Teller’s presentation provoked real anger from Oppenheimer. According to Teller, Oppenheimer dismissed Szilard and his colleagues as unqualified to judge how the war should end, asking, “What do they know about Japanese psychology? How can they judge the way to end the war?” He believed those judgments belonged with officials such as Henry L. Stimson and George C. Marshall. Teller was distressed by Oppenheimer’s harshness toward friends of his, but accepted Oppenheimer’s decision.

Oppenheimer’s position followed the view he had advanced in his June 16 memorandum: he believed the scientific community had already been given an opportunity to express its opinions and that the petition added little. He told Ralph Lapp and Edward Creutz, who had agreed to help circulate it, that the proposed method was “somewhat redundant and probably not very satisfactory.” Creutz, persuaded by Oppenheimer’s frank and non-peremptory manner, told Szilard he wished to abide by his suggestions.

That influence had an immediate procedural consequence. Oppenheimer would not expedite the petition to Washington; instead, it was sent through normal Army channels and arrived too late. The delay did not erase the scientists’ signatures or their argument, but it deprived the appeal of timely access to the officials deciding whether and how the bomb would be used.

Teller’s position and the limits of the appeal

Teller’s own stance complicates the image of a united scientific opposition. Although his later memoir described the use of the bomb without a demonstration or warning as morally deplorable and of uncertain expediency, his July 2, 1945, reply to Szilard expressed a different view. Teller wrote that he was “not really convinced of your objections” to immediate military use. He considered actual combat use potentially the best way to convince everyone that another war would be fatal, and argued that developing the weapon did not give its makers responsibility for deciding how it should be used.

Oppenheimer likewise treated the petition as an unnecessary intervention into decisions he believed belonged to political and military leaders. Yet the episode’s contrasting positions reveal a deeper disagreement: whether participation in making a weapon entailed a duty to challenge its use, and whether scientists’ judgments should enter policy directly or only through established channels. The petition offered a concrete answer to that dispute—a public condition for use—but its route through the Army meant that the condition reached Washington too late to shape the decision.

The petition’s immediate aftermath

Oppenheimer informed Leslie Groves about the petition in a disparaging tone, describing Szilard’s note as another incident in developments Groves had been following. Groves’s aide, Kenneth Nichols, raised the possibility of getting rid of Szilard. Groves rejected that course for the time being, recognizing that firing or arresting him could provoke a revolt among the other scientists. With Oppenheimer also annoyed by Szilard’s actions, Groves believed the problem could be contained until the bomb was ready.

The episode thus ended not with the petition’s demand adopted, but with its circulation managed, its author left in place, and its delivery delayed. The contrast between 155 signatures and the two on the counter-petition registered substantial dissent within the project; it did not translate into control over the weapon’s use. The petition’s failure to arrive in time made that gap between scientific objection and governmental decision especially stark.