The declassified Soviet files show that they developed their A bomb on their own. The declassified US files show that they were right to fear a US unprovoked first strike nuclear attack, so they had good reason to. :sigh:
Those who attempted to give US nuclear secrets to the Russians (things Russia already knew) were, in some cases, motivated by fear of an out-of-control US government -- essentially noble motives.
Until the 1960s, nobody in power in any world government seemed to understand the dangers of radioactive fallout -- they just thought of nuclear weapons as large bombs. We know this from the declassified documents. They should have known better, because the Radium Girls cases are from the 1920s and were front-page in the NYT and Marie Curie was killed by radiation, but they never consulted the biologists and didn't remember the NYT headlines. I guess.
Only when the evidence of radioactive isotopes in children's baby teeth was brought to the attention of JFK and Khrushchev did world leaders start to understand the true nature of the horror they had created, leading to the Partial Test Ban Treaty. Even then, deranged factions in both militaries tried to blow up as many nukes in the atmosphere as possible before the treaty went into effect, poisoning a generation of children even more,
I'm not sure what the conclusion of this is.