Why Albert Einstein’s message to FDR is ‘one of the most influential letters in history’

The atomic bomb is one of the most consequential inventions of the 20th century. It heralded a new era in global politics, society and culture, and its aftereffects echo throughout our lives today. Before its successful testing on 15 July 1945 at Alamogordo, New Mexico and its horrific detonation one month later at Hiroshima, the bomb was developed by a group of physicists working on a top-secret effort code-named the Manhattan Project. The origins of this effort can be traced back to a letter Albert Einstein wrote to President Franklin Delano Roosevelt.

‘This has been described as one of the most influential letters in history,’ says Peter Klarnet, Senior Specialist for Americana, Books and Manuscripts at Christie’s. In Einstein’s concise but insistent note, he alerted the President that Germany could be working on nuclear weapons. ‘Recent work in nuclear physics made it probable that uranium may be turned into a new and important source of energy,’ wrote Einstein. This energy, he warned, could be harnessed ‘for the construction of extremely powerful bombs.’ Given the threat of this development, Einstein urged the US government to initiate its own research into nuclear fission.

On 10 September, the signed but unsent version of Einstein’s letter will be offered at Christie’s in New York as part of Pushing Boundaries: Ingenuity from the Paul G. Allen Collection. The auction is one of a series of three sales from Gen One: Innovations from the Paul G. Allen Collection. Einstein’s letter, one of the collection’s landmark objects, is the only copy in private hands. The other, slightly longer version that was delivered to the President is now in the permanent collection of the Franklin D. Roosevelt Library at Hyde Park, New York.

As a legendary innovator and the co-founder of Microsoft, Mr. Allen was interested in historically significant objects that chronicled technological advancement and was drawn to this pivotal document. The invention of the atomic bomb brought both sweeping devastation and significant scientific developments across the globe. ‘Like every technological advancement, it’s a double-edged sword,’ explains Klarnet, ‘and this letter epitomises that conflict.’

Einstein the advocate

While Einstein was the letter’s author, the idea did not originate with the famed theoretical physicist. In 1938, German scientists Lise Meitner, Otto Hahn and Fritz Strassman discovered nuclear fission, a breakthrough that hinted at the possibility of harnessing atomic energy. The potential use of this discovery for military means alarmed many scientists of the era.

One such person was the Hungarian-born physicist Leo Szilard who, like Einstein, had been driven from his homeland by the Nazis’ rise to power. Szilard, a former student of Einstein’s, had conceived of and patented the idea of nuclear chain reaction before it was realised. He understood the threat it posed in a military setting. Though Einstein was a theoretical physicist and not directly involved in experimental physics, he was one of the most celebrated scientific figures of his time. Szilard knew that a document bearing his signature would hold substantial influence.

‘Einstein became a celebrity after he won the Nobel Prize in physics in 1921,’ says Klarnet. ‘He realised that his voice carried significant weight, and he became very politically engaged. This was the emergence of Einstein the advocate.’

In early July 1939, Szilard and the physicist Eugene Wigner met with Einstein at his home on Long Island. Hitler had recently seized Czechoslovakia, home to some of the world’s only active uranium mines. One of the other main stores of uranium was located in present-day Zaire, then a colony of Belgium. The trio decided to craft a letter to the Belgian Ambassador to the United States warning of the threat. Szilard changed course after speaking with Dr. Alexander Sachs, an influential economist, who recommended the warning be sent to the White House. Sachs, who knew Roosevelt well, offered to deliver it in person.

A second meeting took place on Long Island, where Einstein dictated the letter in German. Unsure of the level of detail to provide to the president, Szilard translated the text into two typed versions of differing lengths. Both were sent to Einstein for his approval and signature. Einstein left the choice of which version to present up to Szilard, but noted that he preferred the longer one. That letter is now in the permanent collection of the Franklin D. Roosevelt Library at Hyde Park, New York.

The birth of the bomb

On 11 October 1939 Sachs met with the President to discuss the letter, but Roosevelt appeared distracted by other concerns. Hitler had invaded Poland in September, sparking a declaration of war from France and Great Britain, and the American administration was consumed with the fallout.

They decided to continue the discussion the following morning, and the gravity of the situation dawned on Roosevelt. ‘Alex,’ he said, ‘what you’re after is to see that the Nazis don’t blow us up.’ What followed was a chain of decisions that culminated in the establishment of the Manhattan Project.

Under the direction of the physicist J. Robert Oppenheimer, the top-secret research and development initiative brought together the brightest scientific minds around the world. Working out of the Los Alamos Laboratory in Los Alamos, New Mexico — called Site Y — Oppenheimer led the secret weapons facility from 1942 to 1945. The project would go on to employ 130,000 workers and cost $2.2 billion by the end of the war.

On 16 July 1945, ‘the Gadget,’ the first atomic test device, successfully detonated in a remote part of the New Mexico desert called the Trinity Site. At the time, Germany had already surrendered to the Allied powers. Yet shortly thereafter, the Japanese government rejected the Potsdam Declaration, effectively refusing to surrender. On 6 August, Roosevelt’s successor, President Harry Truman, authorised the dropping of the atomic bomb on Hiroshima. On 9 August, a second bomb was detonated over Nagasaki. Five days later, on 14 August, the Japanese government announced their plan to surrender.

The complexities of advancement

The nuclear weapons deployed during the Second World War killed and wounded hundreds of thousands of Japanese civilians. Many more would die over the next decades from radiation poisoning. Two Japanese cities went from bustling metropolises to desolate wastelands. Their infrastructure was wiped out, making it nearly impossible for first responders to provide relief. The bombs forever changed the landscape of warfare, and the reality of nuclear weapons continues to shape today’s geopolitical relations.

Einstein, an avowed pacifist, regretted his role in convincing the US government to fund the development of the bomb. He later confided in his friend, the biochemist Linus Pauling, that his life’s ‘one great mistake’ was sending the letter to Roosevelt. ‘One of the most monumental things he did was also one of his greatest regrets,’ says Klarnet. ‘With this letter, he set something in motion, and once it started, he couldn’t stop it.’

In response, Einstein dedicated the rest of his life to advocating for nuclear disarmament. ‘To him, war was the core problem,’ says Klarnet. ‘And the advent of atomic weapons just made it more urgent to end warfare absolutely.’

Einstein’s role in the beginning of the atomic era coupled with his subsequent horror encapsulates the conflict at the heart of scientific and technological advancement. Humanity’s ability to wield the power of the atom brought profound ethical and existential questions to the fore. As we navigate the complexities of the 21st century, Einstein’s quest to invoke science for the betterment of the humankind remains as relevant as ever.