[throw0101c]

> Had information on warheads and the like been properly contained, maybe other countries would not have so easily developed the bomb.

The Soviets had people inside the Manhattan Project / Los Alamos. As the US made progress that information was fed to the Soviets/Russians.

* https://en.wikipedia.org/wiki/Klaus_Fuchs

* https://en.wikipedia.org/wiki/Atomic_spies