Day One
When Hungarian physicist Leo Szilard leaves Europe he eventually arrives in the United States where, with the help of Albert Einstein, he persuades the Federal government to build an atomic bomb. General Leslie Groves selects physicist J. Robert Oppenheimer to head the Los Alamos Laboratory in New Mexico, where the bomb is built. As World War II draws to a close, Szilard (whose idea was responsible for the progress made) has second thoughts about atomic weapons and debates how and when to use the bomb.
The film focuses on the organization and the politics of the whole affair, such as tensions between the scientists and the military, the communist affiliation of many scientists around that time, the (perceived) risks of espionage and the decision whether to use the bomb after Germany is defeated. Concerning the actual scientific work on the bomb, some of it is shown, but not explained, so an understanding of the workings of the bomb is needed to understand what is going on in that respect.
The story starts with Leo Szilard fleeing Germany on the last train out and trying to convince the military that a nuclear bomb can be built and that the Germans are already working on it. In England, his idea is filed and ignored, so he travels to the USA, but there too, he has to wait a year until something is done with it and Project Manhattan is started.
As Germany is being defeated and its scientists interrogated, it is found out that they have not even come close to constructing a nuclear bomb (partly due to bad cooperation by scientists). Despite the fact that no one has the technology now, and the original reason for project Manhattan is gone, work continues. Szilard, who first used Einstein to get his ideas about building a bomb across to the US leaders, now convinces him to join him in writing a letter to the president to do the opposite, namely not to build the bomb, in order to avoid an arms race. 68 scientists sign a petition, but that is held back by the military.
U.S. President Truman is faced with four options: peace talks (which would not have worked because the US did not want the Japanese to keep their emperor), a blockade (which was thought to be cowardly), an invasion (which could cost from 20,000 to a million lives), or dropping the bomb. Another consideration is that the USSR had said they would enter the war against Japan three months after the surrender of Germany and there is a fear that they might not leave. So Truman decides that the best course of action is to drop the bomb on Hiroshima, against the advice of General Eisenhower.
suspenseful