Judith Coplon Socolov (May 17, 1921 – February 26, 2011) was an alleged KGB spy whose trials, convictions and successful appeals had a profound influence on espionage prosecutions during the McCarthy era. In 1949, three major cases against American communists started: Coplon's case (1949-1967), the Alger Hiss-Whittaker Chambers Case (1949-1950), and the Smith Act trials of Communist Party leaders (1949-1958).
Coplon obtained a job in the Department of Justice shortly after she graduated from Barnard College, cum laude in 1943. She transferred to the Foreign Agents Registration section in 1944, where she had access to counter-intelligence information, and was allegedly recruited as a spy by the NKGB at the end of 1944.
Evidence later emerged that Coplon was recruited as a Soviet spy during the early months of 1945. Judith Coplon had a meeting with Vladimir Pravdin, the NKVD station chief in New York City on 4 January 1945. Pravdin was impressed by Coplon who was described as "very serious, shy, profound girl, ideologically close to us." He went on to argue: "We have no doubts about the sincerity of her desire to work with us. In the course of the conversation (Coplon) underlined how much she appreciated the credit we gave to her and that, now knowing for whom she was working, she would redouble her efforts. At the very first stage of her work (Coplon) thought she was helping the local compatriots (the CPUSA)... She thought the stuff acquired by her couldn't represent an interest to the compatriots but could for an organization like the Comintern or another institution bearing a relationship to us. She added that she hoped she was working specifically for us, since she considered it the highest honor to have an opportunity to provide us with modest help". Soon afterwards she was recruited as a Soviet spy (codename Sima).
Judith Coplon became one of NKVD's most valued sources. Coplon's main attention was focused on the main Justice Department counter-intelligence archive that collected information from the various government agencies - FBI, OSS, and naval and army intelligence. She passed to her NKVD contact a number of documents from this archive. This included FBI materials on Soviet organizations in the United States and information on leaders of the Communist Party of the United States.