When I studied at university, I had access to reprinted editions of many American left publications. Among them was Labor Action, the weekly newspaper of Max Shachtman’s Workers Party.

I have never forgotten the headline from an edition in late August 1940. The headline was “Stalin has murdered our comrade Trotsky”. Those first three words are still relevant today: “Stalin has murdered”. Because we now know, decades later, that the assassin was in fact an agent of the NKVD, the Soviet secret police. But back then in August 1940, we did not really know. The assassin had pretended to be someone sympathetic to the exiled Bolshevik leader.

But Shachtman and his comrades knew — knew with absolute certainty — that regardless of who held the ice pick that shattered Trotsky’s skull, the murderer was the man in the Kremlin.

This is what I was thinking when I first heard the news of the death of Alexei Navalny last week. We may never find out the truth of who or what killed him. Maybe he was poisoned — again. Maybe the guards at the IK-3 camp in the far north of Russia found another way. It doesn’t matter. We know beyond a reasonable doubt who killed Navalny just as Shachtman knew who killed Trotsky.

Putin is responsible for the lives of people jailed by his regime. Even if he did not intentionally kill Navalny, or order his execution, it doesn’t matter. He created the conditions that guaranteed Navalny’s death.

Putin has a long history of ordering the killings of people he perceives as threats to his power. These include Alexander Litvinenko, murdered in London using radioactive toxins. Or the investigative journalist Anna Politkovskaya, killed in Moscow. Or Sergei Magnitsky, who like Navalny was murdered in prison. There are many more. Putin has much blood on his hands.

There are many differences between the murders of Trotsky and Navalny. By the time Trotsky was murdered, he no longer represented a serious threat to the Stalin regime. His own supporters inside the USSR had been exiled, imprisoned and murdered — there was nothing left of the old “Left Opposition”. His attempts to create a successor organisation to the old Third International proved unsuccessful. He was certainly right in his criticisms of the Communist regime in Moscow, but hardly anyone was listening anymore.

Navalny, on the other hand, continued to have followers inside Putin’s Russia, as well as some kind of profile overseas. As he was shunted from jail to jail, eventually winding up in the Arctic Circle, he continued to make news. And his death last week, unlike Trotsky’s, prompted demonstrations across Russia resulting in hundreds of arrests.

One might argue that such comparisons are unfair because Navalny was up against an authoritarian regime which for all its brutality is limited in what it can do to its citizens. The totalitarian Stalin regime had no such contraints.

Both Trotsky and Navalny were intelligent and charismatic, both had a vision of a different society than what the Kremlin wanted, and both were seen to have constituted threats to the regime even if they were exiled or jailed. In both cases, the hand of the Kremlin could be clearly seen in their murders.

The facts about Trotsky’s murder did eventually come out. The Stalin regime was convicted by history of its crimes. I am certain that the same will happen to Vladimir Putin and those who serve him. Their crimes will not go unpunished.