Considering Sputnik happened, it's totally possible that USSR could've developed nukes if US had no Manhattan Project.
And if that had happened, US (and rest of world) would've been really screwed. Manhattan Project used 1/7 of all electricity generated in US at the time. No way such gigantic project could've been conceived and completed in peace time in US. And definitely not fast enough if USSR had developed it first.
And if that had happened, US (and rest of world) would've been really screwed. Manhattan Project used 1/7 of all electricity generated in US at the time. No way such gigantic project could've been conceived and completed in peace time in US. And definitely not fast enough if USSR had developed it first.