The Atomic Bomb
On October 11, 1939, FDR received a letter from Albert Einstein. In it, the distinguished physicist described the potential for an atomic weapon and warned that nuclear research was underway in Germany.
Roosevelt responded by forming a scientific committee to study whether a nuclear weapon was feasible. Later, he established the "Manhattan Project," a top-secret effort to build an atomic bomb. At a 1944 conference in Hyde Park, FDR and Churchill agreed to keep the bomb project secret from Soviet leader Stalin. But Russian spies were keeping Stalin informed about its progress.
FDR was prepared to use atomic weapons against both Germany and Japan. But a bomb was not ready for testing until after his death and Germany's surrender. In August 1945, President Harry Truman authorized the use of atomic bombs on two Japanese cities.
The decision to develop atomic weapons is part of a larger issue Americans grappled with during World War II - the bombing of civilians.
During the war's early years, Germany and Japan shocked the world when they bombed cities, killing thousands of civilians. Britain responded in kind. But when America entered the war, it opposed such indiscriminate bombing. American bombers accepted greater risks to bomb during the day - trying to pinpoint military targets and avoid civilian casualties, though such efforts provide unsuccessful.
But as the war dragged on, attitudes changed. Moral opposition to bombing urban areas gave way to a grim strategic conclusion that such actions were necessary to maximize the impact of bombing and win the war more quickly by demoralizing the enemy. By 1944, American bombers were making devastating firebomb raids on Japanese and German cities. A single raid on Tokyo in March 1945 killed nearly 100,000 men, women, and children.