Literally boxcars of "stuff" got shipped to the USSR - oh, yes the head of Lend-Lease - Harry "The Hop" Hopkins!!! One of FDR's favorites!!!
My father, who was a career active-duty USAF Reservist (1950-62, a "retread" for Korea), told me about some of that stuff back in the 1950's. It was common knowledge in the Air Force that Hopkins and Harry Dexter White had been solid red, and that they'd sent nuclear materials over the pole to the USSR in the 40's, but nobody could do anything about it. Some USAAF officer who'd tried to stop a shipment up in Montana or Idaho or someplace had had a can tied to his ass by Hopkins personally, the story went.
There was never any doubt in my dad's mind that McCarthy had been right, but that The Club had hated his guts and ridden him down because he'd tried to crash the party uninvited. Not that they had anything against drunks, but that didn't stop them from telling everyone else about it.
This knowledge weighed on my dad's and other people's minds a lot in the 50's and contributed greatly to the atmosphere of pessimism and worry that dominated the era. But media types never talk about that.