Decoded VENONA intercepts of Soviet espionage messages (which are available online now) established that there were well over 300 Soviet agents in the U.S. in the 1940's and 1950's, many of them in the government. Among the Soviet agents identifed by VENONA were Alger Hiss and the Rosenbergs, whom many have believed to be innocent, but whose guilt is proven beyond even a shadow of a doubt by VENONA.
Other Soviet agents identified by VENONA included:
Lauchlin Currie, senior White House aide to President Roosevelt
Alger Hiss, chief of the State Department's Office of Special Political Affairs
Duncan Lee, senior aide to OSS chief William J. Donovan (the OSS, of course, later became the CIA)
Laurence Duggan, the Secretary of State's personal adviser
Harry Dexter White, senior adviser to the American delegation to the United Nations and assistant secretary of the Treasury
Julius and Ethel Rosenberg, Harry Gold, Klaus Fuchs, and David and Ruth Greenglass, the so-called "Manhattan Project spies," who passed American nuclear secrets to the USSR
Additionally, VENONA proved that American Leftists were actively engaging in Soviet espionage, as it documented many espionage activities by members of the American Communist Party on behalf of the USSR.
What does this mean? Several things, one of which is that the American Left's frequent claim to never have actively engaged in anti-American activities is a big lie. Another is that Senator Joseph McCarthy was indeed generally right, but didn't have all facts in hand and didn't know who the 300-plus Soviet agents really were, because the agency intercepting the messages (SIS) couldn't tell him for security reasons. David Major, former director of counterintelligence programs for the National Security Council, has said that Joseph McCarthy "was right for the wrong reasons." Oleg Kalugin, a retired major general of the KGB, said this about McCarthyism: "It has often been betrayed as an evil, but on the other hand, it was an awakening of America. Not to condone McCarthy, but it was a more realistic approach."
The VENONA intercepts were declassified and released in 1995. If you want to know the facts you can read them and government comments about them yourself at:
www.nsa.gov/docs/venona/
www.cia.gov/csi/books/venona/venona.htm
foia.fbi.gov/venona.htm
Some good online references on VENONA are:
"REMEMBRANCES OF VENONA" by Mr. William P. Crowell, Deputy Director, National Security Agency:
http://history.acusd.edu/gen/text/coldwar/venona-crowell.html VENONA Historical Monograph #1:
http://history.acusd.edu/gen/text/coldwar/venona1.html VENONA Chronology:
http://tms.physics.lsa.umich.edu/214/other/handouts/VenonaChrono.html Interview with David Major:
http://www.pbs.org/redfiles/kgb/deep/interv/k_int_david_major.htm You might also want to read:
VENONA: Decoding Soviet Espionage in America, by John Earl Haynes and Harvey Klehr, (New Haven and London: Yale University Press, 1999. Pp. xiii, 487. $30 cloth.)
Thank you for the info and all of those great links. This is bigger than I ever would have imagined.