Szilard petitioned Truman not to bomb without warning

Person: Leo Szilard
Lived: 1898–1964
Field: Nuclear physics
From: Hungarian-American

The story

Leo Szilard had pushed for an American atomic bomb out of fear that Nazi Germany would build one first. In 1939 he drafted the letter, signed by Albert Einstein, that alerted President Roosevelt, and he worked throughout the war on reactor design at the Metallurgical Laboratory in Chicago. As Germany's defeat approached, his fear changed: he worried that the United States would use the weapon against Japan and set off an arms race with the Soviet Union.

In the spring of 1945 he tried to reach the White House directly. He arranged a meeting with Eleanor Roosevelt to pass on his concerns, but President Roosevelt died before it could take place, and a later meeting with James Byrnes, soon to be Secretary of State, found no sympathy. In June he was among the signers of the Franck Report, which urged a demonstration of the bomb rather than its first use on a Japanese city. That recommendation was rejected.

In July 1945 he drafted a petition to President Truman. It asked that Japan be told the terms of surrender and given the chance to accept or refuse them before atomic bombs were used. Its signers warned that by using the bomb the United States might bear the responsibility for opening the door to an era of devastation on an unimaginable scale. The final version was signed by 68 scientists at the Metallurgical Laboratory, by the Atomic Heritage Foundation's count; other accounts give 70 signers, including scientists at Oak Ridge.

General Leslie Groves strongly opposed the petition, and it never reached the president before the bombings of Hiroshima and Nagasaki in August 1945. It remained classified until 1961.

The petition is a landmark in the history of scientists' efforts to restrain the use of nuclear weapons. After the war Szilard and Einstein created the Emergency Committee of Atomic Scientists, and Szilard went on to campaign for civilian control of atomic energy and for arms control, founding the Council for a Livable World in 1962. The petition helped establish the idea that scientists bear responsibility for how their discoveries are used.

Why it matters

The petition helped establish a tradition of scientists speaking out on the moral consequences of their work, a tradition that shaped the arms-control movement.

About Leo Szilard

Physicist who conceived the nuclear chain reaction in 1933, drafted Einstein’s letter to Roosevelt, co-built the first reactor, then campaigned for the rest of his life against nuclear war.

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Leo Szilard

1898–1964 · Nuclear physics

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