On August 21, 1940, Leon Trotsky died from wounds inflicted the previous day by an agent of the Soviet Union’s secret police, known then as the GPU. The assassination occurred in the context of a historically unprecedented wave of political reaction. In Europe, fascist regimes held power in Germany, Italy and Spain. The Second World War had begun nearly a year earlier with the Nazi invasion of Poland on September 1, 1939, just days after the signing of the Stalin-Hitler Pact. The lives of tens of millions were to be destroyed in the ensuing paroxysm of imperialist violence. This was the terrible consequence of the deliberate sabotage of the revolutionary struggles of the working class by the mass Social Democratic and Stalinist parties in the years that preceded the outbreak of the Second World War.

The assassination of the greatest and last surviving leader of the 1917 October Revolution marked the climax of the Stalinist regime’s eradication of the heroic generation of socialist workers and intellectuals who had secured the victory of the Bolshevik revolution, founded the Soviet Union as the first workers’ state in history, and posed before the international working class the overthrow of capitalism and imperialism as a realizable strategic objective.

By the time Trotsky was assassinated, Stalin’s regime of bureaucratic terror had already murdered hundreds of thousands of revolutionists within the USSR. The frame-up trials held in Moscow between 1936 and 1938, which doomed dozens of the principal leaders of the Bolshevik Party, were only the public manifestation of a broader wave of murderous terror. Stalin’s homicidal rampage was not confined to Old Bolsheviks whom he perceived as a direct political threat to his regime.

The Stalinist terror was nothing less than a war aimed at the extirpation of the entire Soviet culture, profoundly influenced by socialist internationalism, which developed in the aftermath of the October Revolution. Writers, musicians, painters, mathematicians, physicists, biologists, economists and engineers were persecuted, sent to brutal prison camps, tortured and slaughtered. Members of foreign Communist parties, on the mere suspicion of harboring sympathy for Trotsky, were shot en masse. Entire party leaderships were liquidated.

The monstrous crimes committed by the Stalinist regime were carried out under the banner of the “Struggle against Trotskyism.” The unrelenting campaign of hate directed against Trotsky was not only the expression of Stalin’s obsessive desire for revenge against his unyielding political opponent. More significantly, Trotsky represented—in the history he personified and the program for which he fought-—the conscious socialist-internationalist negation of Stalin’s bureaucratic-nationalist regime.

It is a commonplace among most contemporary academics that Trotsky represented no threat to the Stalinist regime. Such cynical appraisals are contradicted by a study of Stalin’s personal archive. Though in exile, without any of the external trappings of power, Trotsky’s specter haunted Stalin. Stalin’s biographer, General Dmitri Volkogonov, has recounted that Stalin had a “special cupboard in his study” where he kept “virtually all of Trotsky’s works, heavily scored with underlinings and comments. Any interview or statement that Trotsky gave to the Western press was immediately translated and delivered to Stalin.” Describing the dictator’s fear of Trotsky, Volkogonov wrote:

The thought that Trotsky was speaking not only for himself, but for all his silent supporters and the oppositionists inside the USSR, was particularly painful to Stalin. When he read Trotsky’s works, such as the Stalinist School of Falsification, an Open Letter to the Members of the Bolshevik Party, or The Stalinist Thermidor, the Leader almost lost his self-control.

For Stalin, the threat posed by Trotsky was not limited to hidden and potential opposition within the Soviet Union. Trotsky’s struggle for the Fourth International—that is, to reestablish socialist internationalism as the program of the working class in all countries—was seen by Stalin as the most dangerous threat to the nationalist policies pursued by the Kremlin in the interests of the ruling bureaucracy.

The assassination of Trotsky in August 1940 was prepared over many years through the infiltration of the international Trotskyist movement in Europe and the United States by agents of the GPU. In the initial stage of their activity, the Stalinist agents sought to disrupt, through factionalism and intrigues, the activities of the small Trotskyist organizations that were part of the International Left Opposition (predecessor of the Fourth International).

Among the first and most significant of these agents were the Sobolovecius brothers—known as Senin and Well—who wreaked havoc within the German section of the Left Opposition, thus undermining its political effectiveness during the two crucial years that preceded Hitler’s rise to power in 1933. Following the political catastrophe in Germany, Senin and Well would continue to play a central and deadly role in GPU operations against the Trotskyist movement, both in Europe and the United States.

Of all the GPU agents, the most notorious was Mark Zborowski, an émigré from Poland who infiltrated the Trotskyist movement in France. With the unflagging assistance of his collaborator, Lola Dallin (who once described herself as his “Siamese Twin”), Zborowski, using the party name “Etienne,” successfully wormed his way into the leadership of the Fourth International. He became the ever-present political assistant of Leon Sedov, Trotsky’s eldest son and the leader of the Fourth International in Europe. With information provided by Zborowski-Etienne, the GPU was able to steal in November 1936 a valuable portion of Trotsky’s archive that had been secretly stored in a research center in Paris. However, in the aftermath of the first trial in Moscow, at which Trotsky and Sedov were sentenced to death in absentia, the Kremlin demanded that its agents find the means to carry out the sentences.

While the Stalinist regime sought to justify its persecution of Trotsky by slandering him as an agent of imperialism, the ruling elites in the capitalist countries left no doubt as to where their sympathies lay in Stalin’s war against the persecuted revolutionary. In the United States, the Moscow correspondent of the New York Times, Walter Duranty, vouched for the legal integrity of the frame-up trials. Countless liberal intellectuals, in the interest of strengthening ties between the American Communist Party and the Roosevelt administration, went to extraordinary lengths to justify the murder of Old Bolsheviks in Moscow and lend credence to the preposterous accusations against Trotsky.

When the first trial began in August 1936, Trotsky was living in exile in “democratic” Norway. His efforts to expose the frame-up were blocked by that country’s Social-Democratic government, which was anxious to avoid giving offense to Stalin. Trotsky and his wife, Natalia Sedova, were placed under house arrest and denied all contact with the press and their own supporters. Trotsky was denied the right to communicate with his closest political assistants. For a time the Norwegian Social-Democratic regime even toyed with the idea of returning Trotsky to the Soviet Union. Finally, with the assistance of the great painter Diego Rivera, the left nationalist government of Lazar Cárdenas granted Trotsky asylum in Mexico, where the aged but still vigorous revolutionist arrived in January 1937.

Trotsky immediately set about to organize a great “counter-trial.” Its purpose was to not only refute Stalin’s charges but also to expose the proceedings as a criminal frame-up. In a public statement denouncing the trial, recorded on film, Trotsky declared:

Stalin’s trial against me is built on false confessions, extorted by modern Inquisitorial methods, in the interests of the ruling clique. There are no crimes in history more terrible in intention and execution than the Moscow trials of Zinoviev-Kamenev and of Pyatakov-Radek. These trials develop not from communism, not from socialism, but from Stalinism, that is, from the unaccountable despotism of the bureaucracy over the people!

What is my principal task now? To reveal the truth. To show and to demonstrate that the true criminals hide under the cloak of the accusers.

Trotsky’s appeal led to the formation of an international commission of inquiry, chaired by the celebrated American liberal philosopher, John Dewey. In April 1937, members of the commission traveled to Mexico where they held public hearings at which Trotsky answered questions dealing with all aspects of his political principles, ideas and activities. He testified for eleven days. The commissioners then returned to the United States, where they pored over the evidence and finally rendered their verdict in December 1937. They found Trotsky not guilty and denounced the trials in Moscow as a frame-up.

The Stalinist regime responded to Trotsky’s exposure of the Moscow Trials by escalating its attacks on the Fourth International. In July 1937, the German Trotskyist Erwin Wolf, one of Trotsky’s most capable secretaries, was kidnapped while on assignment in Spain. He was tortured and murdered. In September 1937, Ignace Reiss—who had defected from the GPU, denounced Stalin and declared his support for the Fourth International—was tracked down by the Stalinist secret police and murdered in Switzerland. The circumstances of Reiss’ murder raised suspicions that he had been betrayed by an agent planted by the GPU inside the Paris center of the Fourth International. The principal target of these suspicions was Mark Zborowski-Etienne. However, with the assistance of Lola Dallin, who wrote regularly to Natalia Sedova in Mexico and portrayed herself and Zborowski as selfless comrades and assistants of Leon Sedov, the accusers of the GPU agent were kept on the defensive.

In February 1938, Sedov suddenly fell ill with what appeared to be a routine appendicitis. He was transported to a hospital—the Clinic Mirabeau—chosen by Lola Dallin. It was known to be infested with anti-Bolshevik Russian émigrés as well as GPU agents. Zborowski informed the GPU of Sedov’s illness and whereabouts. Following a routine operation, Sedov appeared to be recovering. But he suddenly took a turn for the worse, fell into a delirium, and died in agony. The physical cause of Sedov’s death was never precisely determined. The available evidence indicates that he was the victim of either a peritonitis attack caused by deliberate medical malpractice or poisoning. But while the means employed to bring about Sedov’s death remain unknown, there is no reason to doubt—to quote the words of the old Trotskyist Georges Vereeken (1896–1978)—“that Trotsky’s son was deliberately handed over to the GPU killers by Zborowski.”

Following the murder of Leon Sedov, Zborowski and Dallin sent a tender message of condolence to his bereaved parents. However, suspicions against both Zborowski and Dallin mounted, and an effort was made by Trotsky to establish a commission of inquiry. It is believed that Rudolf Klement, the secretary of the Fourth International, was in possession of an appeal from Trotsky for the creation of a commission when he suddenly disappeared from his Paris apartment in July 1938, just six weeks before the founding congress of the Fourth International was to be held. Klement’s decapitated torso was eventually pulled out of the Seine River. Within the space of one year, four major figures in the Fourth International had been murdered. In each case, the GPU assassination squads acted with information provided by Zborowski-Etienne. And with both Sedov and Klement murdered, Zborowski participated in the founding congress of the Fourth International as the official Russian delegate.

As the GPU murdered his closest collaborators and supporters, the preparations for Trotsky’s assassination intensified. Seeking information about and access to Trotsky, the GPU successfully placed an agent in the New York headquarters of the Socialist Workers Party (SWP) in 1938. The agent was a young member of the Communist Party by the name of Sylvia Franklin, who was married to a Stalinist agent named Zalmond Franklin. Louis Budenz—the editor of the Stalinist Daily Worker who was also heavily engaged in anti-Trotskyist espionage operations—introduced Franklin to one of the top Soviet GPU operatives in the United States, Gregory Rabinowitz (alias “John”), who selected her for the assignment. She adopted the party name Sylvia Caldwell, and soon managed to become the personal secretary of SWP national secretary James P. Cannon. In that position, she had access to all communications between Cannon and Trotsky. She systematically copied documents in Cannon’s office and turned them over to the GPU.

Another critical step in the conspiracy against Trotsky was taken when Budenz, again working with Rabinowitz, carefully stage-managed the rekindling of a friendship between Ruby Weill, a member of the Communist Party, and an old acquaintance named Sylvia Ageloff, who had become active in the Trotskyist movement. Weill accompanied Ageloff on a trip to Europe in 1938, and it was there that Ageloff was introduced by Weill to Ramon Mercader, alias “Frank Jacson,” the future assassin of Leon Trotsky.

The GPU also planted agents inside Trotsky’s villa in Coyoacan. Many years later, in May 1956, in the course of a US Senate investigation into Soviet espionage, an American ex-GPU agent by the name of Thomas L. Black testified that he was selected by Rabinowitz to take part in the conspiracy against Trotsky. He told the Senate committee:

First, I was to go to Coyoacan, and there would be other Soviet agents in Trotsky’s household, and I asked him who they would be.

He said that I would find out that when the time came.

Black was asked if he knew the nature of the planned assignment. He replied: “To arrange for the assassination of Trotsky.”

As it turned out, Black did not travel to Mexico and participate in the assassination. However, agents were already in place in Coyoacan, and—as subsequent evidence eventually confirmed—at least one other American GPU operative in the SWP was sent down to Mexico from New York in the spring of 1940 to participate in the assassination conspiracy.

Trotsky was not unaware of, let alone indifferent to, the Stalinist efforts to murder him and strangle the Fourth International. In November 1937, he wrote “An Open Letter to All Workers’ Organizations.”

Never before has the labor movement had in its own ranks so vicious, dangerous, powerful, and unscrupulous an enemy as Stalin’s clique and its international agents. Remissness in the struggle against this enemy is tantamount to betrayal. Only windbags and dilettantes but not serious revolutionists can confine themselves to pathetic outbursts of indignation. It is necessary to have a plan and an organization. It is urgent to create special commissions which would follow the maneuvers, intrigues, and crimes of the Stalinists, warn the labor organizations of dangers in store, and elaborate the best methods of parrying and resisting the Moscow gangsters.

This passage refutes the absurd and lying claim—propagated by the SWP in the aftermath of the assassination—that Trotsky emphatically opposed any discussion of, let alone counter-measures against, the danger posed by the GPU to the Fourth International. The historical record establishes that Trotsky actively sought to expose and counteract the operations of the GPU. These efforts, however, were frustrated by agents already positioned inside the Fourth International.

In late 1938, Alexander Orlov, who had occupied a high position in the GPU, defected from the Soviet Union. He was intimately familiar with the murderous operations of the GPU against the Fourth International. Though his motivations remain unclear, Orlov sent Trotsky a secret communication that identified a certain “Mark” as an agent of the GPU. Though he did not know the last name of the agent, it was clearly Zborowski-Etienne. Trotsky—who did not know of Orlov—immediately sought to make contact with the unknown correspondent. The effort, for reasons that remain unclear, was not successful.

Several months later, Orlov sent a second and even more detailed denunciation of the agent in Paris. The letter also warned Trotsky that a female GPU agent would come to Mexico and attempt to poison him. Shortly afterwards, in the summer of 1939, Lola Dallin arrived in Mexico. Trotsky confronted her with the letter. In testimony later given to a Senate subcommittee, Dallin claimed that she persuaded Trotsky that the letter was a GPU hoax. She told Trotsky: “See how they work? They want that you should break with the only people that are left over in France, Russians, let us say, in France, in Paris.” Despite Dallin’s attempt to discredit the warning, Trotsky attempted again, but without success, to make contact with its anonymous author.

As for Dallin, upon returning to Paris she immediately—according to her Senate testimony—warned Zborowski of the messages Trotsky had received. This information effectively rendered useless Trotsky’s proposal that his followers in Paris secretly track Zborowski’s movements.

In the early morning hours of May 24, 1940, a Stalinist raiding party armed with machine guns, led by the painter and fanatical Stalinist David Alfaro Siqueiros, was able to enter the grounds of Trotsky’s villa on the Avenida Viena. They did not need to scale the walls of the villa or use explosives to blow the front gate open. The gate was opened for them by Robert Sheldon Harte, a 25-year-old Stalinist from New York City who had gained admission to the SWP. With the indifference to security that characterized the SWP leadership, Harte—whose personal and political background was all but unknown—was soon sent to serve on Trotsky’s guard detail.

Miraculously, Trotsky and Natalia managed to survive the assault by slipping under the bed as the assassins sprayed their bedroom with machine gun fire. The raid exposed the utter lack of preparation by Trotsky’s guard detail. After the raiding party retreated from the villa, believing that it had accomplished its mission, Trotsky was the first to walk out onto the grounds. He had to search for his guards. None of them had fired their weapons. The few who had attempted to fight back were unable to do so because their machine guns jammed, apparently because they were using the wrong ammunition.

Almost immediately, well-grounded suspicions were raised about the role of Sheldon Harte in the assault. He disappeared with the raiding party, and eyewitness accounts indicated that Harte had left the villa of his own volition. A picture of Stalin was discovered in Harte’s New York apartment. A dictionary in his possession bore the signature of Siqueiros. Several weeks after the raid, Harte’s body was discovered. Members of the Siqueiros gang had executed him. At that point, Trotsky did not accept the allegations against Harte. But the peculiar and highly suspicious aspects of Harte’s behavior did not allow Trotsky to categorically declare the dead man’s innocence. He left open the possibility that Harte may have been involved in the attempt on his life. In any event, documents discovered after the dissolution of the Soviet Union have irrefutably established that Harte was, indeed, a Stalinist agent. He had been murdered because Siqueiros doubted that he could be trusted with information relating to the organization and execution of the raid.

In the final weeks that remained of his life, Trotsky devoted his immense reserves of energy to the exposure of the Stalinist murder machine. He wrote two major documents relating to the May 24th raid: “Stalin Seeks My Death,” completed on June 8, 1940, and “The Comintern and the GPU,” completed on August 17, 1940, just three days before his assassination.

On August 20, 1940, shortly after five in the afternoon, Frank Jacson arrived unexpectedly at the villa on the Avenida Viena. Following his previous visit, on August 17, Trotsky had expressed displeasure with Jacson’s odd behavior. He voiced doubts about Jacson’s claim that he was a Frenchman. Except for his relationship with Sylvia Ageloff, the nature of his interest in the Fourth International remained entirely unknown and unexamined.

But no notice was taken of Trotsky’s concerns, and Jacson was admitted into the compound. Though it was a warm and sunny day, Jacson was carrying a raincoat, in which he concealed an alpenstock, an automatic firearm, and a large dagger. In violation of the most elementary security procedures, Jacson was permitted to accompany Trotsky alone into his study. Minutes later, while Trotsky reviewed an article written by Jacson, the assassin struck Trotsky from behind with the alpenstock. Jacson had expected that the blow to the head would immediately render Trotsky unconscious. But Trotsky screamed, rose from his chair and fought back against his assassin. Guards ran into the study, and disarmed Jacson.

Trotsky gradually lapsed into unconsciousness as he was driven to the hospital. He died 26 hours after the assault, on August 21, 1940. He was two months short of his sixty-first birthday.

The assassination of Trotsky was a devastating blow to the international working class. To the extent that any one man or woman can be described as politically indispensable to the cause of socialism, Trotsky was such a person. He embodied a vast and unequalled political experience. With the possible exception of Lenin, there was no other figure who played such a monumental role in the political history of the twentieth century. Moreover, seventy-five years after his death, Trotsky remains an extraordinarily contemporary figure. He has not yet passed entirely into history. He is as much a figure of the present as he is of the past. The writings of Trotsky, his theoretical and political conceptions, his revolutionary internationalism, still speak with immense power to the problems of the world in which we live today. Trotsky remains the great voice of the unfinished revolutionary tasks bequeathed by the twentieth century to the twenty-first.