On August 20, 1940, Leon Trotsky was assassinated by an agent of the Soviet secret police, the GPU, in Coyoacán, a suburb of Mexico City, where he was living in exile. Thus ended the life of the great Marxist theoretician of world socialist revolution and one of the towering figures of modern political history.
Trotsky’s assassination ranks among the most politically consequential crimes of the 20th century, with far-reaching implications for the international working class and the world socialist movement. And yet, for decades, the circumstances surrounding the assassination remained shrouded in secrecy. The massive scale of the Stalinist conspiracy against Trotsky was the subject of a carefully orchestrated cover-up.
In 1975, the International Committee of the Fourth International launched the first systematic investigation by the Trotskyist movement into the assassination. This investigation, known as Security and the Fourth International, led to the exposure of the network of GPU and American intelligence agents within the Fourth International that ensured the success of Stalin’s conspiracy against Trotsky’s life and facilitated state surveillance in the decades that followed. The investigation was bitterly opposed by Pabloite and pseudo-left organizations, which denounced the exposure of spies placed inside the Trotskyist movement as “agent-baiting.” This has remained their position, despite the fact that state intelligence documents released following the dissolution of the Soviet Union confirmed the findings of the International Committee and vindicated Security and the Fourth International.
On this page, you can explore the origins and findings of the investigation through interviews and lectures, a timeline, and read some of its major documents.
In this two-part interview, David North, who has played a central role in the investigation into the assassination of Leon Trotsky since its initiation in 1975, explains its principal findings and historical and political significance.
In this webinar, David North and Eric London discuss the results of the WSWS investigation into the role of Sylvia Ageloff in the assassination of Leon Trotsky.
In this lecture, delivered to the 2023 SEP Summer School, Eric London reviews the place of the investigation into Trotsky’s assassination in the decades-long struggle by the ICFI against Stalinism and Pabloite revisionism.
At age 26, Tom Henehan, a member of the political committee of the Workers League, was murdered in October 1977. It was a political assassination, aimed at intimidating the members of the WL, which was then involved in the investigation into Security and the Fourth International. In this tribute, North reviews the political significance of the life and murder of Tom Henehan.
Harold Robins was the first to respond to Trotsky’s anguished appeal for help after he had been struck with an ice pick by the Stalinist GPU assassin, Ramon Mercader, on August 20, 1940. He later supported the ICFI’s investigation into this political crime. His death in 1987 marked the parting from the scene of one of the last living links to Leon Trotsky.
In this statement on the death of Mark Zborowski, the International Committee reviews his role as one of the most murderous agents in the Fourth International.
In this Open Letter, sent to Suzi Weissman, a representative of the Pabloite Socialist Workers Party, David North refutes falsifications and slanderous accusations leveled against the Security and the Fourth International investigation.
This essay reviews how the Socialist Workers Party covered up the role of Sylvia Callen, a Stalinist spy, in enabling Roman Mercader to gain access to Trotsky’s study and murder the revolutionary. When the ICFI launched its investigation, the leader of the SWP, Joseph Hansen, defended Sylvia Callen openly as an “exemplary comrade.” He too was exposed as an agent working for both the GPU and the FBI.
In this series, published in 2021, Eric London reviews major new findings by the Security and the Fourth International investigation concerning the role of Sylvia Ageloff in the murder of Leon Trotsky.
This statement, published on the occasion of the death of Nancy Fields and the 50th anniversary of the initiation of Security and the Fourth International, reviews the origins of the investigation.
In this 2023 lecture, Evan Blake and Tom Mackaman explain the origins of the investigation in the fight against the renegacy of former Workers League national secretary Tim Wohlforth, and the concerted efforts of the Workers League to train a cadre in the history of the Trotskyist movement.
David North delivered this series of lectures on the occasion of the 5th anniversary of the assassination of Tom Henehan and in the early stages of the struggle against the Pabloite degeneration of the Workers Revolutionary Party. In reviewing the theoretical and historical foundations of the training of Trotskyist cadre, the series drew out the lessons of the Security and the Fourth International investigation. To this day, this series plays an important role in rooting workers and young people in the principles of Trotskyism.
In their break from the Trotskyist movement in 1985-1986, the leadership of the Workers Revolutionary Party, which had initiated the investigation in 1975, began to publicly denounce it, joining the witch-hunt of the Pabloites. In particular, the WRP now denounced the case of Alan Gelfand against the US government, which brought to light critical information about the infiltration of the SWP with FBI and GPU agents. In this Open Letter to Cliff Slaughter, Gelfand repudiates their slanderous accusations, and lays out the key findings of his legal case.
Tom Henehan was assassinated on October 16, 1977, at the age of 26. Tom was a member of the Political Committee of the Workers League, the forerunner of the Socialist Equality Party (US), and a leader of the Young Socialists. His murder was a political attack, aimed at intimidating the Trotskyists in the US who had taken a leading role in investigating and exposing the plot to assassinate Leon Trotsky in 1940.
Soon after Tom’s death, the Workers League and the Young Socialists launched a campaign to demand the arrest and conviction of his killers. The campaign won widespread support from workers and youth throughout the country. Under growing pressure from the Workers League’s campaign, the police finally arrested Angelo Torres on a bus in Brooklyn on October 15, 1980. Several months later, in December 1980, after long denying that a second gunman was involved, the police arrested Edwin Sequinot. Both Torres and Sequinot were indicted for murder and attempted murder. This image gallery pays tribute to Tom Henehan and documents of his major political interventions. Readers can learn more about him on this site and on a special dedicated to his memory.
This is the preliminary report on the investigation into Security and the Fourth International. Many more pamphlets and books were published in the years to come.
The International Committee of the Fourth International published transcripts of the key briefs, depositions an court hearings in the Gelfand case in a two-volume edition. The documents are a devastating exposure of the US government’s infiltration of the Socialist Workers Party.
Based on extensive archival evidence, this book sheds new light on how the governments of the United States and the Soviet Union spied on and infiltrated the world Trotskyist movement from the 1930s through the 1980s.