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In the modern AI enterprise, adversaries no longer break in. They log in as autonomous AI agents and machines gain privileged access. Your risk is becoming invisible and legacy tools can't keep up. Introducing Idera from Palo Alto Networks. Idera is the next generation identity platform built for the scale of the AI workforce. It helps you discover hidden risks instantly, eliminate static privileges with just in time enforcement and automate governance at machine speed. Secure every identity, human, machine and agentic with Idera by Palo Alto Networks. Visit paloaltonetworks.com Idira to get started. Welcome to Spycast, the official podcast of the International spy Museum. I'm Dr. Marc Jacobson filling in for Sascha Ingar. Today we're stepping into the hidden world of spies shaping events around the world. For those of you who have visited the International Spy Museum, you may be familiar with one of our most prized artifacts. The ice axe used to assassinate leon Trotsky in 1940. Trotsky was the operational mastermind of the Russian Revolution of 1917. And when Vladimir Lenin died, many assumed Trotsky would succeed him as the central figure of the revolution. Joseph Stalin had other plans, a bitter rivalry that ended in Trotsky's demise. Our guest today, Keith Melton, not only tracked down the murder weapon, but alongside his colleague Nigel west, has written the most comprehensive account of the plot and the assassination to date. Keith and Nigel join me to discuss their book, the Assassination of Leon Trotsky, Espionage Scandal and the Crime of the Century, ahead of their live program coming up on August 6th here at the Spy Museum. Thank you, Keith. Thank you, Nigel, for being here today. I'm really excited to speak to you about the new book, not only because this is certainly going to be one of, if not the definitive history of the Trotsky assassination, but also because the two of you have such a wealth of experience and so many lenses with which to look at not just an intelligence operation, not just Trotsky, but the entirety of subversion, sabotage and assassination. That's not only of historical importance, but we'll get to the issue as it displays itself today in the actions of the Russian state.
A
Well, thank you. We appreciate the Spy Museum giving us this opportunity and we believe that the readers will be quite pleased when they discover all the newness that's built into our manuscript.
B
And I think that's a great place to start because some people will think about Trotsky and his death simply as an assassination with an ice axe. But what your book is getting to is something that's a much larger story. The might of Stalin's intelligence surfaces. This enormous bureaucracy with tremendous capability, focused across continents and across the decade on one man. They penetrate political movements, they exploit personal relationships, and as I said, it ultimately took a decade to succeed. Is this a fair way to think about the new book?
A
It is a fair way to understand how a 60 year old aging man with virtually no money, a cook, a house cleaner, his wife and five volunteer American guards were trying to stand off the might of the assassins of the Soviet Union. And the fact that he survived 11 years is almost a miracle. But it was never a question of if he would die, only when the assassins would get to it.
B
So before we get to that, I'd like if you both could set the scene. Not just who was Trotsky, but why did he matter? Why was Stalin so obsessed with him as a threat? And even after Trotsky had been driven
A
into exile, Trotsky was the last competitor with Stalin to see who would rule the Soviet Union after Lenin's death. Stalin was brilliant and ultimately cleverness and guile out ranked smartness. And Stalin succeeded him. Once he did, immediately began a program to discredit him. And within four years he was excommunicated from the party, kicked out of the Soviet Union into exile. From that moment he was penniless. And as soon as he left the Soviet Union, started writing damning books and articles criticizing Stalin and poking holes in this myth of Stalin. And Stalin very soon would say, my greatest mistake was allowing him to leave the Soviet Union alive. And they began work soon after on a program to kill him and kill his family and kill all of his supporters wherever they were. And it became one of the priorities of the Soviet Union.
B
A major point in the book is that Stalin is not just focused on Trotsky, but on Trotskyism. Destroying Trotskyism as a rival political movement, going after the family followers, anything that could be used to subvert Stalin in an ideological sense. How did Soviet intelligence go about planning and executing that?
C
Well, to start off with, Stalin was not only paranoid, but he saw Trotsky as the greatest threat to himself. He was confident that nobody else could challenge him. And so he gave Trotsky this extraordinary status. And to deal with it, he simply relied on his own secret police. And at that time, at the beginning of the Spanish Civil War, this was a period of terrible bloodletting on every kind of side, with Stalin standing above head and shoulders, above everybody else in his paranoia, determined to get his own way, but seeing enemies everywhere and not trusting anybody and turning to the henchmen that supported Stalin to go after Trotsky. And so it's a convergence of the political era, plus the ability to deploy these ruthless killers, and then finally the madman directing all of this. Who was Stalin?
B
One of the strongest arguments you both make in the book is that virtually every node around Trotsky is penetrated by Soviet intelligence. I know we use the term jpu, GPU to cover all the intelligence organizations, but you speak about how the Socialist Workers Party in New York, the CP USA network, and eventually the Mexico City compound, even the Paris circle around Trotsky's son Lev, are just all penetrated with ease. How complete was JPU's coverage of Trotsky's world and what advantage did that give Moscow?
A
Well, I would say their penetration was without parallel. Trotsky isolated in this self contained fortress. He cobbled together, he had essentially three nodes of communication. One, to the Socialist Workers Party in New York City, which was in effect the Trotsky Party in the United States. The second, his son Lev Sadoff, operating in Paris. And the third was communicating with his publisher, Harper Brothers, and he was communicating to them through a cutout. And the information was systematically provided to the gay payu in Paris. You had almost a similar situation where the number one assistant to Lev Sadov, who was Trotsky's son, the number one assistant, his code name was Tulip. And he had been inserted as a volunteer and became so important that literally Levsedov trusted him with his personal mail, the key to his communications. And any document that he received was given literally that day to the GPU office in Paris. The final note was his communications with Harper Brothers. And the GPU bribed a mailman in New Jersey. And all of the letters from Trotsky were intercepted and sent to a cutout where they were copied, photographed, and then ultimately redelivered to Trotsky. So his communication was completely compromised.
B
Was Trotsky aware of how transparent his communications were to the Soviets, or was he ignorant of that, or did he underestimate it?
A
Trotsky was willfully blind. He was known to having a towering intellect and he believed his ideas were so strong that any person that truly was a follower would see there was no other choice. His way was the only way. And he depended on New York City. That's where they got money for the fortifications and to pay the bodyguards. I depended on them for everything. He depended on Lev Sadoff in Paris to run the rest of the international network around the world. There were at that time an estimated 5000 air active Trotskyites in the world. There were in Mexico, a few hundred. In comparison, there were 5 million people, members of the Communist Party alone. And he was so drastically outnumbered, he had no counterintelligence. So he was not aware of what was happening to him.
C
It was a combination of arrogance and stupidity. And we can say that now because it's really only now that we can make an informed judgment about the scale of the threat and the degree of penetration of Trotsky's organization. He couldn't have imagined how many people around him had been recruited one way or another or put under pressure. This is an extraordinary conspiracy that really hasn't been touched on before, mainly because the VENONA material, which provided a lot of evidence for us in identifying these personalities and their duplicitous behavior, didn't become available until 1995, when it was declassified by the National Security Agency. So it's only now that we can pursue these issues.
B
And Venona, for our listeners, the U.S. army Counterintelligence Program that's able to intercept and decrypt the Soviet traffic. I think this is a really important point you make, Nigel. Could we go into a little bit more about what VENONA adds to the Trotsky case? Especially because this case is so full of COVID names, double identities, FBI intercepts and defectors. If you could discuss that a bit more.
C
Yes. Venona was a cipher system. The word Venona is an American code name. And it remained secret until 1995, when it emerged that the NSA decrypts could be just declassified. And much of the material relates to events concerning a planned escape of the assassin. And so we can see in the VENONA material, which was never intended by the Soviets to be read by anybody outside their own organization. This gives us a brilliant insight to be able to spot the bad people who had committed themselves to supplying information to Stalin.
B
In addition to the discussions of the intercepts, the material that the FBI learns about. How does love, ideology, trust and loneliness. How is that manipulated by the Russians in order to understand how the assassin Ramon Mercator is able to get his mission accomplished? I mean, there's quite a web here of false identities, betrayal. That's just fascinating.
A
They had to penetrate his inner circle because an assassination requires skills, but it depends on opportunity. And to do that, they knew they had to get a source. And there were three sisters, and one of the sisters had been to Moscow. Firm supporter, had met Stalin's wife Another sister named Ruth had been the secretary at the time of hearings that they held in Mexico City to support Trotsky in 1937. And she was seen as friendly to the family. And the third sister by the name of Sylvia was younger, but an idealist, very smart, master's degree in psychology from Princeton. And she was seen as the vulnerable. She had never had a long standing personal relationship. And they said, we will seduce her and manipulate her. They invited her to a meeting in the Paris that was scheduled in the fall of 1938. They had prepared her by conditioning her to believe that Paris was the city of love. And as soon as they landed, they arranged for her to meet a man by the name of Ramon Mercader. And he was the son of Caradad Mercader, who was the lover of General Eitengen, who was one of the key planners of the entire operation. His alias at the introduction was Jacques Monard. He purported to be the son of a retired ultra wealthy Belgian diplomat. And he was purported to be in the university. He was also writing sports articles, purportedly. And he was well dressed, urbane, knowledgeable, spoke beautiful French, he spoke Russian, he spoke Spanish. And he began to court her. He escorted around town for 10 days. And on the night of the 10th night, Caradat, his mother in cohorts with Eidegun, calculated that at this point the relationship had been personal. There was minor flirting. Mercadur was not at that point the assassin. He was simply to get information. And it worked. They ultimately moved back to New York City. Then he announced he's moving to Mexico City. He then wanted her to join him. He was the man of her dreams. And ultimately they used that relationship beginning in January of 1940 to lay what were the final plans.
B
The scene is set, it's 1940. All the players are in Mexico City. Nigel, you and Keith have written that one of the key pieces is figuring out the fortress security. That you can't have an assassination without understanding what the compound is like. And then from there you get into two very different attempts. The first being in May 1940. That's a more military style raid. Can you walk us through what's required in order to set up that first attempt in May 1940?
A
Well, the key was information. You have to have intelligence. And with the five bodyguards and a small entourage, no one entered it. He was the most famous man in Mexico. Hundreds of people wanted to meet him and wanted to be there. Security stopped them. So he began by Sylvia, volunteered to do work and work as one of his transcribers to help him typing up his lectures. And she was there each day. So he would drop her off and then at the end of the day pick her up. Well, he would wave to the guards, they began sharing cigarettes. And so he began to learn what were the security protocols that were in place. That was key were in the new facility. And the Soviets had never had someone inside. And it was a cobbled together summer home of a wealthy family, the Terate family in Mexico City. And they had turned it into kind of a walled fortress. And I surveyed the building, we did the most thorough examination and identified all of its original features, the features that were added. And the Soviets then thought there would be one plan. And the one plan was designed to go on May 24th, 1940. And the Soviets had recruited an American guard by the name of Robert Sheldon Hart. And he's son of a wealthy industrialist in New York City named Jesse Hart. And he was the guard. And he had arranged for himself to be the lone guard on the night of the 23rd of May. And they had actually a GPU officer by the name of David Alfero sicarios. And he was the second most famous muralist in Mexico City. And he had led the Mexican division of the International Brigades that fought in the Spanish Civil war. He selected 24 of the colleagues, the comrades, he paid them a pittance. And. And they were believing that they were going to assault. They could get in the front door very easily. They neutralized the five sleeping or drunk Mexican guards that were supposedly on duty on the outside. And they went in. It was a military operation. Two men used a submachine gun to basically pin the guards in their quarters. They then had two other elements. The first element went in and began burning Trotsky's papers and his documents. But the assassination element targeted a small 10 by 12 foot bedroom where Trotsky and his wife slept in separate beds. And they begin firing into the bedroom from four directions. The outside windows, the bathroom door to the Trotsky's office and the door to the grandson's bedroom. And they fired hundreds of bullets into this small area at the beds they missed, which was inexplicable. And we provide the reason in the book that's never ever been presented of how they missed. And it was simple. The story is that Trotsky and his wife rolled into the corner, she covered him with her body and they kept firing into the twin beds. The twin bed masked the corner. And the assassins sicarios, who was the leader? He never confirmed they were dead. And he Went back and reported to the man that was in effect the leader, a man named Joseph Grigolevich, who was at the front gate controlling the guard. And they pulled out. They believed he was dead for hours, until eventually Mexico City radio reported that he was alive. And this was stunning. With the failure, they then activated plan B, which was to take this true assassin, Mercador, who was then using the COVID name Frank Jackson. And he was elevated from gathering intelligence and he was to be the final assassin.
B
Let's move on to the successful assassination attempt. My biggest question, Keith, is why an ice ax rather than a pistol, a knife or poison? Doesn't this create the situation where everything goes wrong?
A
The choice of weapon is one of the most controversial topics of the entire assassination. And the assassination was controlled, surprisingly, not from Moscow, but from New York City. And the penetration of the CPUSA after this failure, four days later they called Leonoyd Eidengen, who ran the operation in Mexico City. Caridad Mercador, who had been the controller of her son, and the son Ramon Mercader were all called to New York City and they had the meeting in which they had decided that Frank Jackson, Mercadur, he would be the assassin. Stalin wanted this to be a one man operation because he said there was a terrible mistake on the first raid. Too many people knew about it, there were too many mouths now talking, and he feared one of them would somehow link it to Stalin. He wanted a hands off operation. And they could position the assassin to be a unhappy Trotskyite who was so disgruntled with Trotsky that he killed him. And that was the story. He always had a guard with him, or at the most there was a guard 10ft away. And the goal was can we kill him silently and exit through the bedroom of the grandson and from there go out into the courtyard and leave? And this was the idea. So they knew that a gun could kill him, but it would make noise, the guards would immediately come in and he'd never get out. So said they could kill him with a knife. Well, a knife could be fatal. But they had learned that people that have been stabbed do not die silently. They're bleeding, they're wriggling around, they're fighting back, they make a commotion and once again that would alert the guards. But the Russians had experience in killing a diplomat in the Mid east in 1938 who was about to defect, and they considered ways to kill him. Ultimately they found a very powerful seaman. They gave him a diplomatic status and the weapon was a 1 inch iron bar that he wrapped in a newspaper. And when he went into the ambassador's office to present his documents, while he was reading them, the assassin came up behind him, dropped the newspaper and smashed in the back of his skull with this one inch iron bar. He died silently. So from this they had the idea, but Mercadura said, no iron bar. I'm one of the greatest mountaineers there is. I'll use an ice axe, give me the proper ice ax and I can split a boulder of granite with it. So if he could do that with a 1 inch bar, I'll cleave his entire head and he'll die instantly. And that was the plan. But what happened? And once again, this is new news that has never been reported before. In the interim between the failed attempt which took place on 24 May and the assassination on 20 August, in that period, they raised frantically money in America to strengthen their defenses. What they did was to strengthen all their physical defenses, but they never strengthened the fact that Trotsky would never allow visitors to be searched, improbably. And he said, if they're coming here and we trust them enough to let them in, we'll not do them the disservice to then search them. And the guards would live in. But they had no choice. Ultimately, that would be his downfall. Trotsky believed in physical defenses, but not personnel defenses. And what had happened is a very clever engineer from Minnesota visited and he created for the first time a sally port at the entrance. And a sally port is an area usually at the entrance to a police station, where there's one way to get in. A vehicle would pull in or a person comes in, the door behind them closes and there's another locked door in front of them, and they can't enter the compound until that second locked door is open. This was now controlled not from the gate, but from a control tower that was 100ft away and two stories high. So no longer could the guard at the gate control entry. But this also meant that no one could leave the compound without the guard 100ft up in the air sending the signal and opening the door. That took place around the 6th of August, and because Mercur was going in and out, he detected it. And at this point, the only weapon they had access to at that time was to go ahead with the ice axe and believe he would kill him silently go through Trotsky's bedroom, the grandson's bedroom, get out and walk about 30ft to the gate, wave a friendly signal up to the control tower be allowed in. They'd open the final gate outside. He'd go through, wave at the Mexican guards and exit the place. And it could have worked, but improbably it wouldn't.
B
When we come back, we look at one of the book's most powerful claims that Trotsky could have survived the assassination attempt.
A
Well, on the final day he had had a dry run several days earlier and he was the first man basically of the entourage to meet with Trotsky alone. And he was purportedly writing an article to a magazine that would offer intellectual support to Trotsky's positions. Trotsky read a version of it three days earlier. It was garbage and notes all over. He said, this is terrible. Go home and rewrite it. It was on August 20, about 5:30 in the afternoon, wearing a suit. He was always well dressed. He had a confession letter tucked inside his jacket. He was carrying a Clifton raincoat over his arm. He was wearing a very interesting decorative hat with a band around it that caught attention and the guards didn't search him. He's allowed inside. He carried three weapons. He had a dagger or poniard sewn into a pocket in the overcoat. He had a star 44, 45 calories semi automatic pistol inside his left pocket. And he had slit open the lining of the raincoat and had the shortened ice ax which is about one foot long. It was made in 1928, sharpened pick abroad ads. And the plan was to kill him with a strike, with a pick which was to drive the pick into the back of his head so far it would reach the brain stem. It would cause instant death. Now could it be done? Yes, probably a difficult thing to do. While Trotsky was reading this article, he shifted slightly to his right to catch the light coming in from the window. The assassin was behind him. He pulls the ax out and he maneuvers slightly to Trotsky's left because there's an emergency button to sound a siren. He didn't want Trotsky reaching for it. He raised the axe and as he's about to strike the blow, there's nothing stopping him. He closes his eyes and Trotsky sensed something was wrong and turned around to where he's almost facing the assassin. And when the blow fell, it was at an angle. And rather than dying, he lets out this bellowing scream, stands up and begins to attack the assassin. Mercur freezes in fear, has no idea what to do. Trotsky's trying to get the axe and fight back. And he grapples with Him. Finally, Trotsky, it was a mortal and a fatal wound, begins to weaken, and he just stands there. The guards hear the commotion and begin to rush in. They begin beating Mercur to the point he's almost dead. Trotsky goes into the kitchen. He's comforted by his wife. At first, they believe, because it was struck with the pointed part, it went in 2.75 inches. And so the wound opening was about a half of an inch wide and about 3,8 of an inch long. So it was deep and narrow, but it appeared superficial. And the first doctor they call says, he'll be okay. Trotsky's laying there saying, no, I will not. But he hears him beating Mercad and they said, no, he must live. The gay pay did this. Do not kill him. And ultimately, the police arrived. They wanted to rush him to the hospital, but his wife, Natalia will not allow him to be taken away to the hospital because their son Lev Sadaf, had died mysteriously in a Paris hospital in February of 1938 when she was rushed to the hospital. And they feared that this was a ruse and the Stalinists were trying to use a fake hospital crew to get him to the hospital and finally kill him.
B
Now, one of the important new points that you raise is that Trotsky might have been able to survive with even moderate medical care. You described the delays in getting him to the hospital, but what else goes wrong medically? And how close did he come to surviving?
A
Well, when he reaches the hospital, the President of Mexico, Cardenas, sends the five greatest surgeons in Mexico to attend to Trotsky. This is a terrible affront to him that someone has killed Trotsky in his country. Now, as good as they supposedly were, they were very limited. We had two surgeons in the US examine the autopsy report, and we find the brain was bleeding profusely. Well, in the late 1920s in America, we had created a tool for electrical coagulation that they could literally cauterize and stop individual blood vessels from bleeding. And it reduced the bleeding in the brain. This was common even in the Spanish Civil War. The field hospitals during the war had and depended on this. But in all of Mexico, no one did this. So Mexico's leading surgeon said, we can clean the wound. They took out a small portion of the skull called tree planning. And it was small, but it was about four times too small. It should have been four times larger. And so what happened? The brain kept bleeding. The brain was swelling, and it had no place to go. And instead of swelling up through this large section that had been removed, the swelling went downward and depressed the brain stem, which ultimately caused his death. And after the first prognosis, when they cleaned the wound, they said the chance of living is 10%. The Communists quickly called to the US and found the finest brain surgeon in the country who was at Johns Hopkins, named Dr. Dandy. And they arranged for him immediately to fly to Mexico City. But before he could make the arrangements and get to the plane the next morning, Trotsky's medical condition had deteriorated so badly that death was imminent. In a US Hospital, they would have taken out the proper area of the skull and they would have been able to stop the bleeding. In any major city hospital, that could have been done. Now because it was on the right side of the brain. The right side of the brain controlled motor movement and walking and your ability to write, but it didn't control speech. And the belief was that Trotsky, had he lived, would have been physically impaired, probably in a wheelchair, but his mind would have been active, his ability to speak would have been active, and he certainly would have continued with his message for a longer period of time until the next wave of assassins probably finally killed him.
B
Now, this story doesn't end with Trotsky's desk or the assassin's arrest. Nigel, you've written about Soviet efforts to free him, the possibility that Moscow wanted a cleaner ending with the assassin dead as well or dying during an escape. Describe to us the logic of that sort of endgame.
C
Well, the issue relating to nome, which was the code name for the escape attempt, was all based on Mikado. Mikada is arrested, goes to jail, and is interrogated. And during that period, from that moment onwards, the Soviets appear to be planning a very sophisticated escape. So we can now look at Mikada's time in prison. And through looking at the venona encrypted traffic, you can see all the people who were involved in the supposed escape.
A
We make an assertion in the book. We posit the theory that the Russians wanted the assassin to die because had he died during the assassination, the only understanding of what he had done would have been a typed confession in his pocket, and the story would have ended there. Because you can't explain the absence of the one weapon he should have had, which was a suppressed or silenced pistol. The Russians had these. The gay payu had them. They had them in inventory. But somehow, over the years, this took. They couldn't manage to get a suppressed weapon from Moscow to Mexico City. And this is just unbelievable. He could have killed him silently and had a reasonable good chance of getting to the gate and leaving. But they didn't do that. And the only plausible explanation is they wanted him to die in the escape and that would end it. There's even a belief that when he was in prison, he did not use opportunities to escape when they were presented because he feared the Russians more on the outside, that someone would try to kill him during the escape. There was actually more safety in the jail and he was very concerned when the leaders sued a plot of Eiden and and karaded. Mercador went back to Moscow in 1941 and received order of the Red Banner, the highest awards you can receive. But they said, what about for our son, the assassin? And Stalin is famously quoted to saying, well, we'll see how he does in prison. And what he's saying is we'll see if he brokers my name for a letter sentence and he exploits me or if he still holds true. He said at the end, we've had a 20 year prison sentence, then we'll deceive what the award will be. So they were very uncertain. And all of this information on the escape that Nigel did is really being discussed here for the first time. And this assassination theory of mine that they wanted him dead. I think the logic's very good and folks will enjoy reading that part.
B
I think given the current Russian leader's penchant for assassination, this book is not just of historical value, but will be of interest to those who follow current events. The book the Assassination of Leon Trotsky, Espionage, Scandal and the Crime of the Century. Keith Melton and Nigel west, thank you for joining us today on Spycast.
A
Well, thank you so much. One last point. The real Ice Axe is on display as one of our prized exhibits at the museum, and I urge people, whenever they visit, be sure and look at it. It's something that in its own way changed history.
B
Thanks for listening to this episode of Spycast. If you liked the episode, please give us a follow on Apple, Spotify or wherever you get your podcasts and leave us a rating or review. It really helps. And if you have any feedback or want to hear about a particular topic, you can reach us by email at spycast. At spymuseum. Org. I'm your guest host, Dr. Mark Jacobson, and this show is brought to you by N2K Networks, goat rodeo and the International Spy museum in Washington, D.C.
Guest Host: Dr. Mark Jacobson
Guests: Keith Melton & Nigel West
Date: July 28, 2026
Podcast: SpyCast (International Spy Museum)
This episode takes a deep dive into the 1940 assassination of Leon Trotsky in Mexico City, using newly uncovered intelligence material and first-hand artifact research. Guests Keith Melton and Nigel West, co-authors of The Assassination of Leon Trotsky: Espionage, Scandal and the Crime of the Century, discuss Stalin’s decade-long quest to eliminate his rival, the infiltration of Trotsky’s inner circle, the dramatic details of the murder, and the enduring legacy of Soviet assassination tactics. The conversation also draws parallels to modern Russian state behavior.
This episode features a compelling blend of suspense, human vulnerability, Cold War intrigue, and sobering modern parallels. Through technical detail, personal stories, and impactful new scholarship, the guests reveal the chilling precision of Soviet assassination operations and the personal flaws that doomed Trotsky. It’s a gripping account with direct relevance for anyone interested in espionage, power politics, and the lessons history offers today.