That was a really interesting post.
Pinging the others who have posted on this thread to #19.
RE: "The NSA told the FBI about the Venona intercepts but insisted that the FBI could not use NSA intercepts as evidence in court. The FBI had to develop their own leads. As a result most of the spies escaped prosecution. The FBI did not get their man."
An early version of "the Wall?" But recently even without "the Wall" between agencies there appeared to have been walls among FBI personnel -- at least some recent writings about 9/11 are saying it.
.. and Ronald Kessler cites the FBI to impugn Senator McCarthy?!