Physicist Leo Szilard read “The World Set Free” in Berlin in 1932. Its story—of the discovery of atomic power, of the ensuing atomic war that destroyed the world’s major cities, and that war’s outcome—deeply impressed him. About five years later, a number of puzzling experimental outcomes were beginning to suggest the reality of what Wells had proposed (based on his intuition of what Einstein’s 1905 theory of relativity and Frederick Soddy’s work on radiation implied): splitting the atom to release immense energy.

In 1938, when Szilard realized how to create a chain reaction, he remembered Wells’ tale of a disastrous nuclear war. Until Hitler took over in Germany and even for awhile afterwards, discoveries in physics were freely shared internationally. But warned by Wells’ novel to the danger of his discovery, Szilard decided to keep it secret.

Szilard left for America, where he worked with Enrico Fermi, who had emigrated from Italy with his Jewish wife when Mussolini began to adopt Hitler’s persecution of Jews. When Szilard was sure an atomic bomb was theoretically possible, he discussed it with Einstein, who had also recently fled to America from Berlin. As a result of their discussion, they wrote the famous letter to FDR that Einstein signed, warning of the Bomb and the likelihood that Germany would pursue it, and urging the U.S. to develop it first.

Szilard eventually worked on the Manhattan Project, but when Germany was defeated and no German Bomb had been built, he got Einstein to write another letter to FDR, urging that the U.S. Bomb not be used in the war. After FDR’s death, he also led 69 other Manhattan Project scientists to write and sign a similar letter. He argued that using the Bomb against people would undermine the moral authority of the U.S. after the war, especially its ability to bring “the unloosened forces of destruction under control.”

Szilard realized two things that he might also have learned from Wells’ novel: because it was so immensely destructive, the atomic bomb was going to be the center of the largest moral questions the world had ever faced, and the geopolitical reality of the world had changed, because warfare with atomic weapons could destroy civilization and perhaps humankind itself.

These two areas—the moral and the geopolitical—were fused together by the first atomic explosion. They are fused together still. But for the purposes of analysis, let’s look at them separately.