Also, I just think it's amusing that his lists came from the State Department itself.
The History Channel's OTD message for today repeats what we all know:
Senator McCarthy famously announced that he had a list with the names of over 200 members of the Department of State "that were known to the Secretary of State as being members of the Communist Party and who nevertheless are still working and shaping the policy of the State Department.”What's not so famous is that McCarthy's list(s) of names, whatever else they may have been, were "not fictitious."
Have a look at Chapter Four of the history of State's Bureau of Diplomatic Security (here), an official publication of State's Office of the Historian.
McCarthy’s numbers—205, 57, and 81—were inconsistent, but not fictitious. The numbers were derived from testimony by Department of State officials and Division of Security files. An SY [Office of Security] memorandum admitted in April that the “81” figure that McCarthy presented to the Senate was drawn from the “108 Cases,” which had been derived from SY files by a team of House of Representatives researchers in 1947. That group found 108 employees of questionable loyalty working for the Department. The “57” figure was also from the 108 cases; Deputy Under Secretary for Administration John E. Peurifoy had testified to Congress in March 1948 that 57 of the 108 still worked for the Department.(4) The number “205” was also derived from SY figures. In 1946, Robert L. Bannerman’s Security Office and the Department’s Screening Committee had flagged 284 “security risks.” Secretary of State James F. Byrnes reported this to Congress in July 1946, noting that the Department had dismissed 79 of the 284, leaving 205 possible risks. As the Senate’s Committee on Foreign Relations emphasized, McCarthy’s “information was beyond all reasonable doubt … a ‘dressed up’ version of material” previously presented to Congress. Yet McCarthy had so effectively repackaged the numbers that it was several weeks before Department of State officials determined their origins.(5)So, I guess those listed names really were known to the SecState.Footnotes(4) Memorandum, Division of Security, n.d. [April? 1950]. Memorandum “History of 108 Cases,” Division of Security, 6 April 1950, Folder – Administrative Folder, Box 5; and Memorandum “Report on Loyalty Security Performance – 1947-1952,” Conrad E. Snow, Chairman of the Loyalty Security Board, to Dean Acheson, Secretary of State, 8 January 1953, Folder – Loyalty Security Board, Miscellaneous 3/1952 – 3/1953, Box 4; both Security Files 1932-63, A/SY/Evaluations. Committee on Foreign Relations, State Department Employee Loyalty Investigation, p. 8.(5) Oshinsky, A Conspiracy So Immense, 109, 111-112, 156 ( McCarthy quotation on page 156. Committee on Foreign Relations, State Department Employee Loyalty Investigation, 81st Congress, 2nd Session, Senate Report 2108, p. 7, 14-17. Of that report, pages 6-17 make clear the connection between McCarthy’s numbers and the figures and files of the Security Office and of SY. Memorandum, Division of Security, n.d. [April? 1950], p. 6.
There is more detail here on the interplay between McCarthy and his Permanent Subcommittee on Investigations of the Senate Government Operations Committee and the subcommittee of the Senate Foreign Relations Committee (“Tydings Committee”) concerning those lists.