In 1938 German physicist Otto Hahn discovered how to split the uranium atom. Even though published accounts of the scientific breakthrough prevented keeping this knowledge secret, many scientists feared the Nazis might attempt to manipulate such an advancement to further their attack on the nations of Europe. Hungarian scientist and refugee Leo Szilard shared this apprehension -- believing the nuclear energy released during fission could be harnessed to produce bombs capable of severe destruction. Convinced he must act quickly, Szilard persuaded world-renowned physicist Albert Einstein to sign a letter (which Szilard wrote) addressed to President Franklin Delano Roosevelt describing the possible military implications of the German discovery and the urgent need for American research on the subject. Possibly in response to this plea, in addition to the advice of his advisers, FDR appointed the Briggs Committee in October of 1939 to investigate nuclear fission.

The government nonetheless gave little priority to the development of an atomic bomb until the fall of 1941. Sparked by positive results from British scientists studying the feasibility of atomic weapons as well as intelligence reports that the Nazis already had begun tests of their own, FDR authorized an intensive research effort in the United States. The shock of Pearl Harbor and the continued success of the Nazi military campaign in Europe served as reaffirmation that the American government must proceed at full speed to discover the secrets of atomic energy before the Axis Powers.

In June of 1942 the War Department's Army Corps of Engineers took charge of the effort to develop an atomic bomb. The subsequent top-secret project (code named Manhattan) cultivated a complex, but cooperative relationship between science, industry, the government, and the army. Although research took place across the nation, an obscure lab in Los Alamos, New Mexico became the central site in the effort to produce an atomic weapon. By 1944 both the United States and Great Britain realized Germany no longer had any realistic chance to develop an atomic bomb. Yet instead of slowing the momentum of the Manhattan Project, FDR stressed the need for the continuation of research and development; although Germany failed to pose a viable threat, Japan's reluctance to surrender signaled the possibility of a long and costly battle in the Pacific. Therefore, the government no longer viewed the bomb as a defensive weapon to protect the world from the Nazis, but as a way to save American lives and money by shortening the war against Japan.

Unaware of the intricacies surrounding the atomic bomb development in the United States, Harry Truman was briefed by presidential advisers concerning the confidential Manhattan Project two weeks after FDR's death. While at the Potsdam Conference in Germany only a few months later (July 1945) Truman received word of the successful test of an atomic bomb in the New Mexico desert. Until this meeting of the Allied nations, American and British officials failed to disclose any information to Soviet leader Josef Stalin regarding their attempts to build a new weapon. Resentful of the belligerent Soviet foreign policy in Eastern Europe, Truman and Churchill hoped their military secret would provide them with a post-war diplomatic advantage against Stalin. So, although originally conceived as a short-term solution in a military conflict, the atomic bomb eventually evolved into a vital tool of the political maneuvering between the two superpowers that emerged following the Second World War.


Research by Kathleen Johnson,
Volunteer for the Cold War Museum

Works Cited:
Bundy, McGeorge. Danger and Survival. New York: Random House, 1988.
Hershberg, James C. James C. Conant. New York: Alfred A. Knopf, 1993.
Stoff, Michael B., Fanton, Jonathan F., Williams, R. Hal, eds. The Manhattan Project. Philadelphia: Temple University Press, 1991.
Nobile, Philip, ed. Judgment at the Smithsonian. New York: Marlowe & Company, 1995.

To learn more about Japan's research on atomic weapons, visit Axis History Forum - Atomic plans returned to Japan