The Manhattan Project Target Committee meetings of May 10 and 11, 1945, translated the prospective use of the atomic bomb into choices about targets and warnings. Held in J. Robert Oppenheimer’s office at Los Alamos, the meetings exposed a divide between the committee’s operational planning and a scientist’s appeal to give the Japanese an opportunity to evacuate. Morrison’s proposal was quickly rejected, leaving him with the sense that those building the weapon had little influence over how it would be used.

Setting and purpose

The meetings took place in the spring of 1945 as the Target Committee considered where the bomb might be used. The official minutes record agreement that a target should be in a large urban area more than three miles in diameter. The participants also discussed the emperor’s palace in downtown Tokyo, bringing the political and symbolic center of Japan into the target deliberations.

Phil Morrison attended as a technical expert. A former student of Oppenheimer and, after transferring from the Met Lab in Chicago, one of his close friends at Los Alamos, he was positioned to speak within the planning process, but not to determine its terms. His recollection later supplied a view of the discussion that the formal minutes did not: how a proposal to warn civilians was received in the room.

The warning proposal

Morrison argued for some kind of formal warning if a demonstration of the bomb proved impractical. He thought even leaflets could give Japanese civilians a chance to leave. An unidentified Army officer rejected the proposal, reasoning that a warning would allow the Japanese to prepare to attack the aircraft carrying the bomb. The objection framed warning as an immediate operational danger; the possibility of evacuation did not alter the committee’s course.

Oppenheimer did not support Morrison. Morrison later recalled that he was given a hard time and excluded from making any real comment. David Hawkins, who was also present, corroborated the substance of Morrison’s recollection: Morrison proposed a warning and an opportunity to evacuate, while the officer argued vehemently against it. The episode records both the proposal and its limits: Morrison could raise the humanitarian alternative, but the discussion did not give it traction.

Decisions and limits of influence

The official record and Morrison’s account illuminate different aspects of the meetings. The minutes show the broad target criterion and the discussion of Tokyo’s palace; Morrison’s memory shows a warning being proposed and dismissed. Together they describe a planning process in which an urban target was treated as a practical requirement while a warning was rejected on military grounds.

Morrison came away believing that the scientists had little influence over what would happen. That judgment gains context from the subsequent May 31 meeting of the Interim Committee, which advised the secretary of war on atomic policy. Although Oppenheimer and other scientists attended as consultants, the question of whether to use the bomb against Japan was not on the agenda; military-use decisions were understood to rest with the White House. The Target Committee meetings thus mark a narrower but consequential stage of the process: deliberation over targets and warning took place, while the scientists’ ability to redirect the outcome remained sharply constrained.