Within 4 months we shall in all probability have completed the most terrible weapon ever known in human history, one bomb of which could destroy a whole city.
These words began a memo that was drafted by Secretary of War Henry Stimson and presented on April 25, 1945, to President Truman. Truman had been president less than two weeks, and, with the help of General Leslie Groves, Stimson provided Truman’s first, in-depth introduction to the Manhattan Project on that day.
On May 8, 1945, Germany, its war machine defeated and many of its cities in ruins, had surrendered. Even in the face of Germany’s defeat, the pace of development of the atomic bomb intensified at Los Alamos, Oak Ridge, and Hanford. Looming in the near future was the test of the implosion-based gadget, the so-called Fat Man atomic bomb. In late February, the date for the test had been set; named Trinity, the test would occur in early July.
Fear of a German atomic bomb, which, given Germany’s deep reservoir of scientific talent, seemed likely for the first few years of the war initially drove the scientists of the Manhattan Project. But like many science and engineering projects, once it got going, the Manhattan Project moved with the inertia of discovery. Years later, J. Robert Oppenheimer, director of the work at Los Alamos said:
When you see something that is technically sweet, you go ahead and do it and you argue about what to do about it only after you have had your technical success. That is the way it was with the atomic bomb.
He wasn’t the only Manhattan Project scientist and engineer to feel that way, but it wasn’t a universally shared position.
At the University of Chicago’s Metallurgical Laboratory, known informally as the Met Lab, the pace of research and development had slowed enough to allow the scientists to catch their collective breath. Met Lab scientists were had responsible for ground-breaking work on the chemistry of plutonium and the physics of nuclear chain reactions, but both of those programs were foundational, early-days items. As the spring of 1945 made way for the summer, Met Lab scientists, particularly Leo Szilard, began to think about the future. As ever, the future concerned Szilard.
As Richard Rhodes says in The Making of the Atomic Bomb, Szilard was “the man who had thought longer and harder than anyone else about the consequences of the chain reaction.”
The government, too, was finally beginning to wrestle with the nuclear genie threatening to escape its bottle. On May 9, 1945, the Interim Committee met for first time. The Interim Committee, composed of academics, military leaders, and politicians, was created to provide guidance and develop policy on nuclear affairs as the United States ventured into an uncertain nuclear future. The committee was chaired by Stimson and advised by a Scientific Panel comprised of Arthur Compton, Ernest Lawrence, Robert Oppenheimer, and Enrico Fermi. The scientists on the panel were told to report any issues to the committee in a blunt and open manner. Compton, a Nobel Prize winner, was the leader of the Met Lab, and he took it upon himself to gather and convey the concerns of the researchers under his leadership.
Compton decided to convene yet another committee; this one consisted of Met Lab senior scientists. This sub-sub-committee was led by yet another Nobel Prize winner, James Franck, and its members included Szilard and future Nobel Prize awardee Glenn Seaborg. Bruce Cameron Reed’s book, The History and Science of the Manhattan Project, has this to say:
Franck’s committee […] was to prepare a report on “Political and Social Problems” associated with the bomb. Working over the week of June 4-11, they drafted a document known as the Franck Report, which is now acknowledged to be a founding manifesto of the nuclear non-proliferation movement.
One of the more provocative recommendations made in the Franck Report was the call for the atomic bomb to NOT be used against Japan. Instead, the Franck Report called for a “technical demonstration” of the weapon. Numerous concerns generated this suggestion, but they all centered on the reality that the United States couldn’t hope to maintain a monopoly on nucleonics, which was then the favored Met Lab term for all things related to atomic science.
The Franck Report was given to the Interim Committee on or about this date in 1945 (some sources say June 10, others say June 11, whereas others refer to mid-June). The committee passed it on to the Science Panel for their thoughts. The Science Panel wasn’t of one mind, and their thoughts ranged from support for technical demonstration—in a remote part of the desert or perhaps on an island—to the outright use of the weapon against Japan. On June 21, 1945, the Interim Committee recommended the military use of the atomic bomb.
The Trinity test went ahead as planned in July, and the first two atomic bombs were dropped on Hiroshima and Nagasaki in early August. World War II came to a close shortly afterwards.
For more in the series Countdown to The Cold War, click Countdown to The Cold War.