The initial stages of the investigation uncovered recently declassified documents, which revealed the conspiracy that prepared Trotsky’s assassination and the fatal role played by agents who had managed to infiltrate all the major political centers of the Fourth International. The ICFI uncovered documents relating to the activities of agents such as Mark Zborowski, who became the principal assistant of Trotsky’s son, Leon Sedov. Zborowski played a key role in the murder of Sedov and other leading members of the Fourth International in Europe. Another important Stalinist agent, who supplied the Kremlin with valuable information on Trotsky’s activities was Sylvia Caldwell (née Callen), the personal secretary of James P. Cannon. But the most significant information uncovered by the ICFI related to the activities of Joseph Hansen. Documents discovered in the US National Archives, and others obtained through the Freedom of Information Act, revealed that Hansen, immediately after the assassination of Trotsky, sought out and established a covert relationship with high-level US government agents. One such document, a letter from the American Consul in Mexico City to an official in the State Department, dated September 25, 1940, reported that Hansen “wishes to be put in touch with someone in your confidence located in New York to whom confidential information could be imparted with impunity.”^[1]

The ICFI discovered conclusive evidence that Joseph Hansen had functioned as an agent inside the Trotskyist movement. A lawsuit brought by Alan Gelfand against the US government, alleging state control of the Socialist Workers Party, forced the release of official documents that substantiated the findings of the Security and the Fourth International investigation. Among the most significant facts uncovered as a result of the lawsuit was that the FBI had known, from at least the mid-1940s, that Joseph Hansen had worked for the GPU inside the SWP. He had been identified as a Stalinist agent by former Communist Party leader Louis Budenz, the same man who had publicly exposed Sylvia Caldwell. This revelation made clear why Hansen and the SWP leadership vehemently denounced Budenz and defended Caldwell. To admit the truth of Budenz’s allegations against Caldwell would lend substantial credibility to his identification of Hansen as an agent. Thus, up until the court-ordered release of Sylvia Caldwell’s grand jury testimony, in which she admitted to having worked inside the SWP as a GPU spy, the SWP defended her as an “exemplary” comrade. Reba Hansen, the wife of Joseph Hansen, lied publicly about the reasons for Caldwell’s sudden departure from the party in 1947 (the year Budenz’s revelations were made public). Describing Caldwell as “a warm human being,” Reba Hansen claimed that “Sylvia left New York in 1947 because of family obligations.”^[2] SWP national secretary Jack Barnes, in testimony given during the trial of Gelfand’s lawsuit, declared that Caldwell “is one of my heroes after the harassment and what she’s been through in the last couple of years.”^[3]