Einstein to Roosevelt, August 2, 1939

In the summer of 1939,

six months after the discovery of uranium fission, American newspapers and magazines openly discussed the prospect of atomic energy. Most American physicists, however, doubted that atomic energy or atomic bombs were realistic possibilities. No official U.S. atomic energy project existed.

Hungarian-born physicist Leo Szilard was profoundly disturbed by the lack of American action. He had conceived the idea of a nuclear chain reaction in 1933, and kept his ideas from publication with a secret British patent. He had warned colleagues about the danger for years. Yet even the discovery of uranium fission, followed by proof that it released neutrons, had not lessened their disbelief.

If atomic bombs were possible, as Szilard believed they might be, Nazi Germany could gain an unbeatable lead in developing them. It was especially troubling that Germany had stopped the sale of uranium ore from occupied Czechoslovakia.

Unable to find official support, and unable to convince Enrico Fermi of the need to continue their experiments at Columbia University, Szilard turned to his old friend Albert Einstein. He had collaborated with Einstein in Berlin in the 1920s on the invention of novel refrigerators without moving parts. Now, he sought Einstein’s help about a very different matter.

Einstein was enjoying a sailing vacation in Peconic on the northern tip of Long Island, New York. On or about July 12, Szilard and fellow Hungarian physicist Eugene Wigner made the short drive from Manhattan in Wigner’s car. Einstein, true to his simple tastes, greeted his visitors wearing an undershirt and rumpled, rolled-up pants. He showed them to his cabin’s large, screened-in porch.

Szilard explained the state of international research on uranium and the evidence that a bomb might be possible. Given the seriousness of the situation, Szilard’s request was quite modest. He asked if Einstein would warn the Belgian Queen Mother, whom he knew, to prevent the large stockpile of uranium ore in the Belgian Congo from falling into Nazi hands. Einstein agreed to the idea, but he preferred to write to another friend, the Belgian ambassador. Einstein dictated a letter in German, which Wigner took down.



Einstein and Szilard re-enact their discussion for 1946 documentary

Within days, however, the plan became much more far-reaching when Szilard discussed the matter with economist Alexander Sachs. Sachs, who was an unofficial adviser to President Franklin Roosevelt, urged that Einstein should write directly to the President. If Einstein wrote such a letter, Sachs promised to deliver it to the President personally.

If they could gain the ear of the President, the Belgian uranium ore became a minor issue. Szilard produced a four-page draft letter, which he mailed to Einstein on July 19. By telephone, Einstein asked to discuss it with Szilard in person.

In the last days of July, Szilard returned to Einstein’s vacation cabin. Because Wigner was out of town, Hungarian physicist Edward Teller acted as Szilard’s chauffeur. Einstein again greeted his guests informally, wearing old clothes and slippers. He served them tea on the shady porch while they discussed the new approach.

Einstein was willing to write to the President. As a life-long pacifist, he opposed the making of weapons. He had been forced to conclude, however, that pacifism would not succeed against the Nazis, who viewed violence as an end in itself. He could not, he decided, let his inaction give Germany sole possession of such destructive power. His only objection was that Szilard’s letter was long and somewhat awkward. He preferred a shorter message stressing the main points. Einstein dictated a short draft in German, which Szilard took down.

Over the next few days, Szilard translated Einstein’s dictation, going through draft after draft. In the end, he prepared both a short and a long version. On August 2, he mailed them to Einstein. Einstein returned both versions signed, but he expressed a preference for the longer version. This was the version, dated August 2, that Szilard gave to Sachs for delivery to the President.

Einstein’s letter did not reach the President quickly, however, nor did it have much effect. On September 1, 1939, Hitler invaded Poland and World War II began. Sachs finally met with the President on October 11 and presented Einstein’s letter. The President appointed a “Uranium Committee,” but it approved only $6,000 to buy graphite and uranium for experiments Szilard proposed. Even that small sum was not provided promptly.

For years, as Hitler conquered Europe, official skepticism continued to stall American progress. A large-scale U.S. atomic project, still limited only to research, did not begin until December 6, 1941, one day before the bombing of Pearl Harbor. It became the “Manhattan” Project in August 1942.

Several months later, thanks to Szilard’s efforts, construction of the first nuclear reactor was completed as soon as sufficient uranium and graphite were made available. Its design was essentially the same as he had proposed in July 1939. The reactor, named CP-1, operated successfully at the University of Chicago on December 2, 1942.

Photos from re-enactments filmed for 1946 March of Time documentary Atomic Power, used under license from CriticalPast. Images of Einstein letter from FDR Presidential Library.