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Jay Vivian Chambers (April 1, 1901 - July 9, 1961), known as Whittaker Chambers, was an American editor who denounced his Communist spying and became respected by the American Conservative movement during the 1950s. After early years as a Communist Party member (1925) and Soviet spy (1932-1938), he defected from communism (underground and open party) and worked at Time magazine (1939-1948). Under subpoena in 1948, he testified in what became Alger Hiss's perjury (espionage) trials (1949-1950) and he became an outspoken anti-communist (all described in his 1952 memoir Witness). Afterwards, he worked briefly as a senior editor at National Review (1957-1959).

Hiss filed a $75,000 libel suit against Chambers on October 8, 1948. Under pressure from Hiss's lawyers, Chambers finally retrieved his envelope of evidence and presented it to the HUAC after they subpoenaed them. It contained four notes in Alger Hiss's handwriting, sixty-five typewritten copies of State Department documents and five strips of microfilm, some of which contained photographs of State Department documents. The press came to call these the "Pumpkin Papers" referring to the fact that Chambers had briefly hidden the microfilm in a hollowed-out pumpkin. These documents indicated that Hiss knew Chambers long after mid-1936, when Hiss said he had last seen "Crosley," and also that Hiss had engaged in espionage with Chambers. Chambers explained his delay in producing this evidence as an effort to spare an old friend from more trouble than necessary. Until October 1948, Chambers had repeatedly stated that Hiss had not engaged in espionage, even when Chambers testified under oath. Chambers was forced to testify at the Hiss trials that he had committed perjury several times, which reduced his credibility in the eyes of his critics.  The five rolls of 35 mm film known as the "pumpkin papers" were thought until late 1974 to be locked in HUAC files. Independent researcher Stephen W. Salant, an economist at the University of Michigan, sued the U.S. Justice Department in 1975 when his request for access to them under the Freedom of Information Act was denied. On July 31, 1975, as a result of this lawsuit and follow-on suits filed by Peter Irons and by Alger Hiss and William Reuben, the Justice Department released copies of the "pumpkin papers" that had been used to implicate Hiss. One roll of film turned out to be totally blank due to overexposure, two others are faintly legible copies of nonclassified Navy Department documents relating to such subjects as life rafts and fire extinguishers, and the remaining two are photographs of the State Department documents introduced by the prosecution at the two Hiss trials, relating to U.S./German relations in the late 1930s.  This story, however, as reported by the New York Times in the 1970s, contains only a partial truth. The blank roll had been mentioned by Chambers in his autobiography Witness. But in addition to innocuous farm reports, etc., the documents on the other pumpkin patch microfilms also included "confidential memos sent from overseas embassies to diplomatic staff in Washington, D.C."; worse, those memos had originally been transmitted in code, which, thanks to their (presumably) having both coded originals and the translations forwarded by Hiss, the Soviets now could easily understand.
Whittaker Chambers