Germany's scientists seem to have purposely slowed down their research on the weaponization of nuclear fission, itself a German discovery.

German physicists had, already in 1939, concluded that 'in principle atomic bombs could be made', but, Werner Heisenberg delayed and de-emphasized the possibility, as he 'did not want the Führer to get so interested that he would order great efforts immediately to make the atomic bomb'.

In September 1941, at the Heisenberg-Bohr meeting in Copenhagen, Werner Heisenberg asked Niels Bohr to ask scientists in the USA to also do as he had, to prevent 'grave consequences in the technique of war'.

When Bohr asked Heisenberg if a nuclear weapon was even possible, Heisenberg replied that he personally knew that it was. He even produced a drawing that showed how a reactor would produce the uranium or plutonium necessary to build an atom bomb. This was a very dangerous move, as it would have been considered treason.

Heisenberg furthermore informed Bohr that he was in a position to neutralize the German nuclear effort. But he also pleaded for Bohr to get 'Allied' scientists to do the same. He hoped that the international physics community could cooperate to spare the world of this horrendous weapon.

Bohr would have none of it. US teams pushed even harder to build the grotesque weapons of mass destruction. Once this was done, the USA would then use them on cities-full of civilians, women, children, etc., for no justifiable reason. The USA, far from desperate, was completely intact from the war, had suffered no civilian casualties, and was in no danger whatsoever.