That's a fact!
The Venona papers proved McCarthy was essentially right, even if his own personal flaws allowed him to go too far (probably out of frustration and being demonized from the get-go), and
make some charges and name some names who were “innocent”.
Not just Venona, but tons of other scholarship proved Communist infiltration at the highest levels of government.
It was,needless to say, FDR , his worldview,and the choices he made, that made that possible.