Groves, Leslie Richard

Groves, Leslie Richard (1896-1970), general of the United States Army Corps of Engineers and, during World War II (1939-1945), director of the Manhattan Project, the vast program that developed the atomic bomb.

Groves was born on August 17, 1896, in Albany, New York, the son of a U.S. Army chaplain. In 1913 he entered the University of Washington in Seattle, transferring the next year to the Massachusetts Institute of Technology in Cambridge. In 1916 he went to the United States Military Academy at West Point, New York, and was commissioned a second lieutenant in the Army Corps of Engineers upon graduation in 1918.

Groves soon won a reputation as an efficient and highly capable engineer who completed large-scale projects on time. However, he was also regarded by some as arrogant and difficult to work with. In 1941 Groves was put in charge of constructing The Pentagon, the headquarters of the U.S. military and one of the world’s largest office buildings, in Arlington, Virginia. By 1942 he was responsible for all U.S. military construction projects.

In September 1942 Groves was promoted to temporary brigadier general and selected to direct the project to develop and build the world’s first atomic bomb. Groves made many of the key decisions regarding the bomb. He decided to pursue simultaneously the most promising technologies proposed for separating fissionable uranium, U²³⁵, which was needed to build the bomb, from natural uranium, U²³⁸. He then supervised the construction of the huge facilities needed at the three most important sites used in the bomb’s development—Oak Ridge, Tennessee; Hanford, Washington; and Los Alamos, New Mexico—recognizing that to be successful the bomb had to be built on an industrial scale. He was in charge of a workforce of almost 175,000 people and supervised the spending of about $2 billion (as measured in 1945 dollars). Groves imposed a security so tight that the project was conducted in almost total secrecy.

In 1942 Groves appointed J. Robert Oppenheimer as the scientific director of the top-secret bomb design laboratory at Los Alamos. Groves had overruled Army intelligence, which refused to confirm Oppenheimer’s appointment because of his alleged associations with Communists. In return, Oppenheimer repeatedly defended Groves against the objections of other Los Alamos scientists. Accustomed to free scientific communication, the scientists hated the draconian security measures Groves imposed on them. At Los Alamos those restrictions were eventually lifted.

Groves was known for his unrelenting drive and ability to solve problems. As director of the Manhattan Project, he had wide-ranging powers and became extremely influential. His influence affected the ultimate decision to drop atomic bombs on the Japanese cities of Hiroshima and Nagasaki.

After the war, Groves played an important part in keeping the military in control of administering the nuclear weapons (and hence, nuclear energy) program. This aroused objections from some scientists, who had hoped for greater influence in putting the program on a more international footing. As the Cold War between the United States and the Soviet Union developed, Groves failed to maintain his support for Oppenheimer. Groves testified at the scientist’s security hearing in 1954 when Oppenheimer was dismissed from the Atomic Energy Commission, saying he would not approve a security clearance for Oppenheimer at that time although he had done so during the war.

Groves left the Army in 1948, having attained the rank of lieutenant general (temporary), and became vice president for research at the Remington Rand Corporation (later Sperry Rand). He retired in 1961 and died in 1970 in Washington, D.C.