This is the second part of the lecture on the most recent developments in Security and the Fourth International, delivered by Eric London to the 2025 Summer School of the Socialist Equality Party (US). The first part, delivered by Thomas Scripps, is here. This concludes the publication of the lectures at the school.
In a four-part series published in February 2021, the WSWS refuted the 80-year-old unchallenged narrative that Sylvia Ageloff was an innocent dupe who was used by Mercader to gain access to Trotsky. This public persona was invented by Ageloff and Mercader in the immediate aftermath of the assassination and later promoted by the Socialist Workers Party and Joseph Hansen. The actual facts concealed by the pathetic tale of “Poor Little Sylvia” were never seriously investigated. The narrative acquired a mythic status, but this myth has no basis in reality.
The Myth of Poor Little Sylvia was promoted by various sources. In The Chosen, the 2016 film by Antonio Chavarrias, Ageloff is played by Hannah Murray according to the myth. The same was true with The Assassination of Trotsky, the 1972 film by Joseph Losey, in which Ageloff was played by Romy Schneider.
One of the earliest inventors of the myth of Poor Little Sylvia was Joseph Hansen, who wrote in With Trotsky To the End, in the immediate aftermath of the assassination: “For months [Mercader] did not come near Coyoacan but stayed in Mexico City. When Sylvia Ageloff, his wife, who was well known to the household, came to Mexico, he did not attempt to enter the house with her.”
Decades later, in Healy’s Big Lie, in a section titled “The Case of Robert Sheldon Harte,” Hansen again promoted the myth: “The odor of the old GPU slanders against Harte, we see, still persists in the headquarters of the Workers Revolutionary party. There is no thought there that Harte might have been victimized by Jacson the way Sylvia Ageloff was victimized.” The myth of “Poor Little Sylvia” therefore became a crutch for the defense of other agents, including Harte.
Even after the publication of the four-part series, the pseudo-left has continued to attack Security and the Fourth International.
Nathanial Flakin of the Morenoite Left Voice wrote in a June 23, 2022 article that Security and the Fourth International was a “vile conspiracy theory” which “never came up with anything more than the most laughably circumstantial evidence.”
Flakin was, and will remain, unable to challenge any of the evidence uncovered in Security and the Fourth International. It is his goal to present as “laughable” attempts to maintain the physical independence of the revolutionary movement from agents of the state, regardless of the evidence, for the same reason that the Pabloites defended Sylvia Franklin even after the testimony of her admitting to being a GPU agent was released to the public. They are not opposed to state infiltration of their movements because their movements are not politically opposed to capitalism and the capitalist state. It is notable that Flakin wrote his article attacking our “laughable” evidence of GPU penetration over a year after the World Socialist Web Site established that Sylvia Ageloff was a GPU agent and a linchpin in the GPU plot to kill Trotsky. He could not respond to it. Nobody could.
In contrast to the middle class radicals, here is how the IC explained security in the introduction to How the GPU Murdered Trotsky:
The assassination of Leon Trotsky in Mexico City on August 20, 1940 was the greatest crime of the 20th century and the highest expression of the counterrevolutionary character of Stalinist reaction. In the months prior to the attack, Ramon Mercader, alias Frank Jacson, an agent of the Stalinist secret police, the GPU, had ingratiated himself into Trotsky’s compound, where the leader of the Russian Revolution had been living in exile since January 1937. Mercader entered the compound, and then Trotsky’s guards, including Joseph Hansen, allowed the assassin to meet with Trotsky in his office, alone. Mercader pulled out the ice pick he had hidden in his raincoat and used it. Trotsky died the next day at the age of 60.
Mercader’s access to Trotsky hinged on his relationship with Sylvia Ageloff. After the attack, Ageloff consistently presented herself as Mercader’s unwitting dupe, a claim never directly challenged by the SWP. For decades, the broader Trotskyist movement and popular culture reinforced this image, failing to scrutinize the contradictions of Ageloff’s story or the political context of the time.
Mercader, operating under the aliases “Jacques Mornard” and later “Frank Jacson,” entered Trotsky’s fortified villa thanks to Ageloff’s endorsement. The SWP, principally responsible for Trotsky’s security in its capacity as the US section of the Fourth International, did not conduct a substantive investigation into the GPU infiltration efforts or into Ageloff’s actions. The party actively discouraged discussion of infiltration, labeling such concerns as “agent-baiting.”
Sylvia Ageloff was arrested by the Mexican police for her role in the events, charged as an accomplice, and prosecuted. Her conviction was forestalled by outside intervention, while the SWP neither reported the ongoing investigation nor questioned her narrative.
Ageloff’s background
Sylvia Ageloff was raised in a prosperous, politically active family and spoke multiple languages, including French and Russian. Ageloff’s family background provided access to sophisticated networks in the US and abroad. Her sister Hilda had traveled to the Soviet Union in 1931, securing an interview with Lenin’s widow—a feat that would have required the approval of high-level Stalinist officials, likely Stalin himself. Her 1931 published article about Soviet education in the New York Times were openly pro-Stalinist, showing no sympathy with the persecuted Left Opposition and praising the dismissal of Lunacharsky.
Ruth Ageloff, Sylvia’s younger sister, became Trotsky’s secretary in Mexico City on the recommendation of SWP leaders. Ruth’s later husband, John Poulos, was a prominent union activist who subsequently joined the Shachtmanite Workers Party; his brother, Constantine Poulos, had close ties to the Greek Communist Party and worked for a press agency connected to British intelligence.
Sylvia Ageloff herself was not only from a family with radical and complex political ties, but she was highly educated—earning a master’s in psychology at Columbia University in 1934. Her scholarly work focused on “suggestibility,” with particular attention to how authority figures influence perception and behavior, a fact at odds with the notion that she herself could have been so easily deceived by Mercader. Her dissertation, “A Study of ‘Prestige’ and ‘Objective’ Factors in Suggestibility,” examined how children responded to figures they respected, and concluded that individuals often abandon common sense under such influence. Ageloff was, by all accounts, analytical, observant, and accustomed to critical evaluation—qualities that contradict the legend of her being a passive, gullible victim.
Politically, Ageloff was an early and active participant in several radical left groups. She and her sisters joined the American Workers Party (AWP) in the 1930s, later merging into the Workers Party (US) and ultimately the Socialist Workers Party. Within the SWP, Ageloff gravitated toward Martin Abern, who was the center of a New York-based clique, before eventually supporting Shachtman in the 1940 split.
Ageloff and Mercader, July 1938-May 1940
Ageloff later described her 1938 trip to Europe, where she met Mercader, as a vacation. But at the time, the stated purpose of the trip was to attend the clandestine founding congress of the Fourth International—a period when Trotskyists in Europe were being systematically hunted by the GPU. Despite this, her traveling companion, Ruby Weil, was an active Stalinist and GPU agent, and Ageloff later testified under oath that she was aware of Weil’s Communist Party ties at the time. This alone raises substantial concerns: Why would a trusted Trotskyist, traveling for sensitive political purposes during one of the most perilous periods for the movement, associate intimately with a known Stalinist? Correspondence and interviews confirm that Ageloff was well aware of the Weil sisters’ political alignments and family connections, making the claim of ignorance increasingly untenable.
When she met “Jacques Mornard” in Paris, Ageloff developed a relationship with a man who openly claimed to be the son of a Belgian diplomat, was always flush with cash, and offered a background story riddled with inconsistencies. She never saw him work nor ever read a published article by him, despite his posing as a sports journalist. Ageloff, with her advanced training in psychology and her personal experience in political circles under threat, evidently chose to overlook—or willfully ignore—every red flag.
The security environment surrounding the Trotskyist movement in the late 1930s was incredibly dangerous. The Soviet GPU (later NKVD) had begun a campaign of infiltration and targeted killings. Trusted Trotskyist cadres, particularly those who gathered in Paris for the clandestine founding of the Fourth International, were being hunted by GPU agents, some of whom gained access through personal relationships. Trotsky’s European secretary, Rudolf Klement, was murdered and had his body mutilated during this period. Despite these well-known dangers, Ageloff associated closely with individuals later proven to be Stalinist agents, including Ruby Weil. She also introduced Mercader—with his ever-shifting stories and shadowy finances—to leading Trotskyists at the founding conference of the Fourth International in Paris, where extraordinary precautions were taken.
Nevertheless, she took him to the founding conference, where he mingled with guests from many countries and passed on information to the GPU.
After establishing a cover story of her meeting with Mercader, Ageloff’s actions directly facilitated his access to the Trotskyist movement and, ultimately, into Trotsky’s household in Mexico. Mercader came to the US in 1939 under his new alias “Frank Jacson,” despite severe restrictions on immigration, and, through Ageloff, rapidly achieved unprecedented intimacy with the movement in the US.
Ageloff’s French associates, including Marie Craipeau, grew suspicious of the generous payments she received from Mercader for translation work and ghostwriting. Such jobs rarely existed at such high pay, and when questioned, Ageloff falsely attempted to explain Mercader’s behavior as that of an infatuated lover. Her subsequent invitation of Mercader to the September 1938 founding conference of the Fourth International resulted in the future assassin spending hours socializing in the garden with leading Trotskyists. Trotskyists from several countries met Mercader through Ageloff’s introduction, further entrenching him in the international movement’s milieu, all while he worked for the GPU.
Next, Mercader came to the US on Ageloff’s invitation. The outbreak of World War II increased the security dangers. By September 1939, as Hitler invaded Poland and global migration ground to a halt, Mercader—now calling himself Frank Jacson—used a forged Canadian passport to enter the United States. Despite strict Roosevelt-era immigration restrictions, judicial records show that an “Executive Order” was issued to facilitate his entry, suggesting either powerful external intervention or use of forged contacts to bypass controls. The fact that the leadership of the immigration service allowed him in despite his traveling on fake documents raises serious questions that merit further investigation about the role of the US government in facilitating the assassination, and also perhaps shed additional light on the role of double agents like Hansen.
Ageloff assisted in this process, providing references and vouching for Mercader as he integrated into the SWP’s New York social circles. Friends of Ageloff, including Lillian Pollak, would later describe their own suspicions of Mercader, based on his demeanor and his lack of verifiable background.
Next, in early 1940, Ageloff arranged for time off from her job in New York to travel to Mexico, where Mercader was by then based. There she became a frequent visitor at Trotsky’s heavily guarded home in Coyoacán, further leveraging the trust her family and personal relationship had secured over time. Mercader soon followed, and Ageloff took up the role of integrating him into the social fabric of the Trotskyist circle in Mexico. Not only did she fail to alert Trotsky or his guards to the still-unfolding inconsistencies in Mercader’s identity and actions, but she continued, even after credible suspicions arose, to support his presence.
Throughout 1940, significant warning signs emerged. Notably, Ageloff recounted later to police that she had grown concerned about Mercader after discovering that his business address in the Ermita Building did not exist. Instead of reporting this directly to Trotsky’s security detail or withdrawing from the relationship, Ageloff continued her involvement and later claimed to have attended with Mercader a Stalinist-organized rally where Trotsky was publicly denounced. She later claimed to believe that Mercader might be a British spy, reflecting a strategic alibi to muddle the true origins of her suspicions.
In March 1940, before temporarily returning to New York, Ageloff personally brought Mercader into Trotsky’s home for the first time, granting him an opportunity to observe the villa’s layout and household routine. This would prove critical for the GPU’s planning and was likely a key moment in the ultimate success of the assassination. Access to the interior and the chance to build trust with the guards made the May 24 attack feasible.
After the May 24 attack, Mercader’s assignment
On May 24, Trotsky’s home was the target of a major armed assault orchestrated by Stalinist painter David Alfaro Siqueiros. Attackers entered the compound, fired hundreds of rounds, and attempted to kill Trotsky and his family and destroy confidential archives, only failing by chance. Trotsky’s grandson was shot. The attackers, importantly, had intimate knowledge of the compound’s layout—information very likely gleaned through insider access facilitated by Ageloff and others. Among Trotsky’s personal security team was Robert Sheldon Harte, later uncovered as an agent working for the GPU.
After the failed May assault, security around Trotsky was theoretically strengthened. But lessons from the attack, such as the need to thoroughly vet those entering Trotsky’s inner circle, went mostly unheeded. Meetings between SWP leaders in Mexico and associates such as Mercader continued to occur, often enabled by previous introductions or recommendations made by Ageloff herself. Throughout this period, the chain of access always led back, directly or indirectly, to her.
After the May attack, the task of carrying out the assassination fell on Mercader, who traveled back to New York to meet Ageloff and his GPU handlers to discuss the plans and to write a letter that was likely intended to result in Trotsky’s guards killing him when they discovered it on his person in the event he was able to carry out the attack.
Mercader appeared to buckle under the pressure of the new assignment. Ageloff was sent back to Mexico later that summer because Mercader began to suffer a mental breakdown as the task fell on him to carry out the assassination after the May 24 attack failed. This fact was confirmed by Volkogonov decades later.
In July and August of 1940, unusual behavior by Mercader began to attract attention within Trotsky’s circle. He alternated between social withdrawal and fits of talkative bravado, sometimes boasting about his physical prowess and his affinity with Trotsky’s enemies. Ageloff made the extremely costly flight down to Mexico City to get a hold of the situation.
Despite increasing wariness from Trotsky and his wife, Natalia Sedova, Ageloff intervened to allay suspicions, and even lied to Sedova by claiming she was engaged or married to Mercader. This lie proved instrumental in persuading the household to grant him continued access. During this period, Trotsky expressed growing unease, reportedly telling associates he feared he would fall victim to someone who had been given access to the house.
On August 17, just days before the eventual murder, Mercader made an unannounced visit to Trotsky’s home, seeking to discuss an article purportedly inspired by a political debate with Ageloff. This encounter, which involved Mercader sitting menacingly close to Trotsky with his coat draped across his arms, only deepened Trotsky’s suspicions. He told Sedova he did not wish to see “Jacson” again, sensing an impostor behind the polite façade.
On August 20, 1940, the day of Leon Trotsky’s assassination, Mercader and Ageloff began the morning at the Hotel Montejo in Mexico City. Mercader left the hotel at 9 a.m., returning around midday. Ageloff would later claim that he explained his tardiness to her as the result of long waits at the US Embassy to arrange their return to the United States. Per Ageloff, she suggested a walk to calm him, during which they encountered Otto Schüssler—one of Trotsky’s long-time aides and guards and a man with substantial experience in the workers movement on security questions—and his wife. The couples exchanged pleasantries and Ageloff explained that she and Mercader planned to visit Trotsky that afternoon to say farewell before supposedly leaving due to Mercader’s ill health.
Ageloff insisted on having Schüssler join them for dinner out of the compound, but he tried to defer to the next day, only relenting after Ageloff pushed him. They scheduled to meet at 7:30 p.m. During this midday meeting, Mercader acted nervously, eventually excusing himself abruptly.
That evening at the Swastica restaurant, Schüssler and his wife arrived for dinner but only Ageloff appeared, claiming Mercader had urgent business with one “Mr. Viñas.” In reality, he had already entered Trotsky’s compound in Coyoacán, falsely assuring guards that Ageloff would soon arrive as well, making his arrival seem routine. When Schüssler grew concerned about Mercader’s whereabouts, she told Schüssler not to call the Trotsky home.
Mexican investigation
Ageloff, upon discovering the assassination, feigned hysteria and obstructed initial questioning, further complicating the investigation. Mexican police, unconvinced by her apparent distress, arrested Ageloff as a possible accomplice. Medical officials soon declared that her hysterics were performed rather than genuine; physiological measures like her heart rate remained unaffected during supposed panic attacks. During interrogation, Ageloff’s responses were often inconsistent, bewildered, or evasive. Investigators and colleagues alike grew increasingly skeptical of her innocence, with some openly declaring her an accomplice or, at minimum, a shockingly negligent party. Her employer in New York dismissed her, citing both her absence and the “low moral turpitude” of her actions.
A key episode during police proceedings was the confrontation of Ageloff and Mercader. Rather than aiding the authorities, Ageloff indulged in histrionic calls for his death, echoing the cover stories crafted by the GPU intended to shield the broader conspiracy and prevent deeper investigation. She did not confront him with any of the information she had acquired through her relationship with him, which could have helped establish his connections to the GPU. Her demand for his death, instead of indicting him with the facts she uniquely possessed, ran counter to the Trotskyist method of confronting crimes not with retributionary violence, but with political exposure.
By 1940, Ageloff had accumulated substantial experience as a socialist and Trotskyist, operating through years of Stalinist terror. Her failure to take action—a failure spanning from initial associations in Europe to the final hours in Mexico—cannot be credibly explained as mere innocence or emotional dependence. Multiple records and witness accounts emphasize that Sylvia Ageloff’s intervention was indispensable to the success of the GPU’s plot. Had she not repeatedly vouched for or reinforced the standing of Mercader, it is doubtful he would have succeeded in gaining the necessary access. Her conduct, intentional or the result of reckless disregard, proved catastrophic for Trotsky and the international movement.
Research by Mexican criminologist Barrón Cruz has proved vital to a better understanding of the response of Mexican authorities to the assassination. The Mexican authorities, under the government of President Lázaro Cárdenas, approached the murder of Trotsky as a matter of national sovereignty and prestige, assigning senior investigators—most famously criminologist Alfonso Quiroz Cuarón—to handle the inquiry. Their investigation was notable not only for its thoroughness but also for its impartiality amid immense international pressure. From the start, investigators were suspicious of Ageloff’s narrative that she was merely an unwitting victim, drawn into the plot through her romantic involvement with Mercader.
The scrutiny of Ageloff’s explanations for her behavior began with interviews that showed significant inconsistencies in her account compared to other witnesses and Mercader himself. Prosecutors quickly amassed a body of circumstantial evidence that contradicted her claims of ignorance and innocence. Central to these doubts was her involvement in organizing the dinner with the Schüssler family, which investigators believed was orchestrated to ensure that key members of Trotsky’s security detail would be absent, giving Mercader the best opportunity to strike. Ageloff’s admissions that she had family in Russia, and her acknowledgment of having witnessed Mercader communicating in code and being extraordinarily secretive with his correspondence and belongings, only deepened suspicion as to why she had failed to report critical details to Trotsky or the authorities.
Further complicating her situation, financial investigations revealed that Ageloff received substantial sums—over $3,000, a considerable amount at the time—from Mercader, which she claimed to have deposited in a New York bank, although she could not recall the name. Mexican prosecutors further suspected these were espionage-related funds, as Ageloff’s income as a psychologist made her extensive travels otherwise inexplicable. This same pattern of financial transfers was highlighted by the FBI as a hallmark of Soviet clandestine operations, with Agent Raymond E. Murphy noting that such deposits were typical in cases involving GPU (Soviet secret police) co-conspirators.
The FBI conducted its own investigation, drawing similar conclusions to their Mexican counterparts. Agents pressed Sylvia Ageloff and her family to cooperate, believing she withheld information that could unravel the internal workings of the GPU’s espionage apparatus. FBI memoranda described Ageloff as emotionally manipulative and implied that her fits of hysteria were calculated performances. In their view, she was a hard, secretive individual who might never divulge the full extent of her involvement. They described her as a “tough cookie” who would likely never divulge all she knew about the assassination.
Former GPU operative Whittaker Chambers told the SWP he, too, could not believe in the innocence of the Ageloff sisters, stating that only extreme ignorance or willful blindness could explain Ageloff’s failure to recognize Mercader’s espionage activities. Chambers characterized such secretive households—marked by family members in both radical and non-political circles—as typical of GPU infiltration tactics. His comments, confidentially shared with the SWP and later relayed to the US State Department by Joseph Hansen, influenced further covert inquiries by federal authorities.
As the murder trial began in Mexico City, the GPU and its sympathizers launched a campaign of intimidation. Judge Raúl Carrancá Trujillo, who presided over the case, and prosecutor Francisco Cabeza de Vaca both received death threats warning them against exposing the assassination’s origins or implicating the Soviet Union. Their determination to follow the evidence regardless of such hazards was instrumental in producing the most complete investigation of the crime.
Prosecutor Cabeza de Vaca’s filings, expressed in the distinctive legal prose of the Mexican criminal system, outlined a litany of facts tending to show Ageloff’s guilt. He argued that, although not physically present during the attack, Ageloff’s knowledge of previous threats, her privileged access to the Trotsky household, and her clear awareness of Mercader’s lack of Marxist background, numerous aliases, false addresses, and secretive conduct, all pointed to her complicity or, at the least, to her gross negligence. He contended that a properly loyal, intelligent friend of the household would have reported these anomalies long before the murder. On this basis, both Ageloff and Mercader were charged with homicide and imprisoned pending trial.
The press widely reporting Ageloff’s incarceration. Defense attorneys sought her release, but the judge consistently sided with the prosecution, echoing the view that her actions defied any innocent explanation. Prosecutor Cabeza de Vaca’s subsequent filings elaborated on how Ageloff’s actions could only be explained by her foreknowledge of the plot. He further emphasized that Ageloff’s financial and logistical support to Mercader, especially given her limited salary and repeated international trips, was inexplicable absent an espionage-related motive.
The Ageloff family used diplomatic channels, with her father directly appealing to US authorities and the Mexican president for her release. There were also moves to protect her sister Hilda from arrest, as Mexican authorities considered broadening the investigation to include her as a possible accomplice. Ageloff was ultimately released despite consistent protest from the Mexican prosecution. It appears clear from FBI documents that high-level intervention, motivated by a mixture of diplomatic expediency and intelligence objectives, resulted in a political decision to drop the most serious legal charges against Ageloff. A living relative of Ageloff told me in a phone discussion that the release was secured with a large suitcase full of cash. Ageloff returned to the United States, whereupon she and her family publicly declared their intent to put the episode behind them and refused to testify further in the ongoing Mexican case.
The statement Ageloff released flatly contradicted the established record. She denied that she had played any role in introducing Mercader to Trotsky or facilitating his access. She further claimed to have been merely an admirer of Trotsky with no political affiliations, an assertion belied by years of documented socialist activism and Trotskyist involvement.
Prosecutor Cabeza de Vaca was assassinated in 1943, a presumed victim of the same Stalinist network he had attempted to expose. His grandson, later a high-ranking Mexican government official, publicly credited his grandfather’s investigation with having revealed the true nature of the assassination conspiracy long before it became accepted fact. Mercader, the assassin, was eventually released from prison and honored by the Soviet and Cuban governments, while Ageloff lived out her life in comfortable obscurity in New York, never seriously inconvenienced by her central role in the greatest political killing of the era.
In 1950, Ageloff, her sister Hilda, and Ruby Weil were summoned before the House Un-American Activities Committee, which was investigating American ties to the Trotsky assassination. The committee was interested in the broader GPU network, linking the Trotskyist murder to Soviet espionage in the United States and the later infiltration of atomic and military secrets. Ageloff downplayed her political connections, again characterized her European travel as a pleasure trip, and responded to questions in a manner that suggested calculated evasion. Nevertheless, the committee offered a public statement saying the sisters cooperated fully and had furnished “valuable information,” a diplomatic formulation suggesting off-the-record disclosures rather than a genuine exoneration.
The accumulated evidence from Mexican and US archives, combined with witness testimony and circumstantial facts, overwhelmingly challenges the myth that Sylvia Ageloff was a naive, manipulated bystander.
In the three years since this series was published, nobody has presented a shred of evidence to contradict any of the information we presented. The concluding paragraph of the series stands: “Based on all the information that is now available, it is possible to replace the myth of ‘poor little Sylvia’ with an accurate account of her role in the political catastrophe of August 20, 1940. The real person finally takes the place of the constructed persona. Who was Sylvia Ageloff? The evidence leads overwhelmingly to the conclusion that she was an agent of the GPU who played a critical role in the assassination of Leon Trotsky.”