Cynthia C. Kelly is President of the Atomic Heritage Foundation. This article is drawn from a series on the atomic bombings of Hiroshima and Nagasaki, "Perspectives on Hiroshima," published by the Federation of American Scientists. Read the full series here.

On September 17, 1942, General Leslie R. Groves took command of the Manhattan Engineer District for the Army Corps of Engineers, assuming direct responsibility for all aspects of the atomic bomb project. As Robert S. Norris documents, Groves proved himself “the Manhattan Project’s indispensable man.”[1]

Groves was a force of nature, extremely driven and ambitious. As Stephane Groueff discovered in researching the Manhattan Project, “Each time precise instructions were missing, [Groves] didn’t ask. He acted.”[2] On paper, General George Marshall, Chief of Staff for President Roosevelt, was responsible for overseeing the Manhattan Project. But according to Groueff, “General Marshall’s contacts with Groves were infrequent…Almost as removed as the president and Stimson, Marshall did not keep in direct touch with the Manhattan Project’s command, except at the very end, when the bomb was almost ready.”[3] As commander of the top-secret project, Groves was virtually unchecked.

General Leslie R. Groves’ son, Richard H. Groves, reflected, “[General Leslie Groves] was very, very competitive. He played games not to play games, but to win…He always spoke of the Navy as being content to have ‘moral victories.’ He said there’s no such thing as a ‘moral victory.’ There’s a victory or otherwise, you lose. And he was after winning.”[4]...