I notice in pop culture this reference to The USSR obtaining the Atomic Bomb through espionage. Then there’s the whole Rosenberg debacle. Is there truth to this or is it more of hype of pre-McCarthyism?
This recent thread touches on this. There was certainly actual espionage that occurred (though the Rosenberg part of it was pretty minor compared to other kinds). But the Soviets didn't use the information in a straightforward way, which complicates the question of whether the espionage was how they "obtained" the bomb.