President Truman decided that a domestic policy on atomic energy had to be adopted before the issue of international control could be addressed. The War Department favored the May-Johnson bill, which would give the military a prominent role in atomic matters. The bill was also backed by J. Robert Oppenheimer, who’d become a celebrity since the end of the war, renowned as “the father of the atomic bomb.” But the legislation was vehemently opposed by most of the young scientists who’d worked on the Manhattan Project. For years they had resented the strict, compartmentalized secrecy imposed by General Groves. Few of the Manhattan Project scientists had been allowed to know how the atomic bomb would be used. Many now regretted that both Hiroshima and Nagasaki had been destroyed. They considered themselves far more qualified than anyone in the Army to make decisions about atomic energy — and warned that passage of the May-Johnson bill could turn the United States into a secretive, totalitarian state. Some still had an idealized vision of the Soviet Union and thought that the War Department’s bill would endanger world peace. At the heart of the debate were fundamentally different views of who should control the atomic bomb: civilians or the military.
Physicists representing groups like the Federation of American Scientists and the Association of Los Alamos Scientists traveled to Washington, D.C., testified before Congress, wrote editorials, gave impassioned speeches, and publicly attacked General Groves. An ambitious first-term senator from Connecticut, Brien McMahon, soon embraced their cause, asserting that the atomic bomb was too important to be left in the hands of “a militaristic oligarchy.” He was particularly upset that General Groves would not tell anyone in Congress how many atomic bombs the United States possessed or where they were kept — and that Groves refused to share that information with Cabinet members, the Joint Chiefs of Staff, or even the secretary of war. President Truman backed the Army’s insistence that details of the atomic stockpile should remain top secret, for the sake of national security. But he sided with the young scientists on the issue of civilian control and threw his support to legislation sponsored by Senator McMahon.
McMahon’s bill, the Atomic Energy Act of 1946, was passed by Congress in a somewhat amended form and signed into law by the president. It created an Atomic Energy Commission (AEC) run by civilians and a Joint Committee on Atomic Energy that provided congressional oversight. Members of the military could serve on a liaison committee that advised the AEC, but they could not determine the agency’s policies.
The president was given the sole authority to decide how many atomic bombs the United States should have, when they should be handed over to the military, and whether they should be used against an enemy. One person now had the power to end the lives of millions, with a single command. All of the laboratories, reactors, processing plants, fissile material, and atomic bomb parts belonging to the Manhattan Project were transferred to the AEC. Civilian control of the atomic bomb was now an American principle firmly established by law — but that did not prevent the military, almost immediately, from seeking to undermine it.
“We are here to make a choice between the quick and the dead,” Bernard Baruch told a gathering of United Nations delegates on June 14, 1946, at the Hunter College gymnasium in the Bronx. “We must elect World Peace or World Destruction.” Baruch was an elegant, silver-haired financier in his midseventies who’d been asked by President Truman to offer a proposal for international control of the atomic bomb. The “Baruch plan” called for the creation of a new agency, affiliated with the U.N., that would own or control “all atomic-energy activities potentially dangerous to world security.” The agency would have the power to inspect nuclear facilities throughout the world, so that any attempt to make nuclear weapons could be discovered and severely punished. The new system of international control would be imposed in stages — and would eventually outlaw the manufacture, possession, or use of atomic bombs. The United States was willing to hand over its “winning weapons,” Baruch said, but would require “a guarantee of safety” stronger than mere words.