Soviet Agents in Republican Spain
Soviet aid to the Republic was not limited to the supplies of armaments and military support in general. It also included work carried out through the official Spanish and Catalan Communist parties, the Communist Party of Spain (PCE) and the United Socialist Party of Cataluña (PSUC), to provide political and military influence with the aim of gaining control over other forces on the left participating in the conflict.
In addition, the beginning of this aid coincided with Stalin’s unleashing a purge of Trotskyist enemies, both within the Soviet Union and internationally. This campaign was transferred to Spain through the Comintern and carried out by the aforementioned parties and by agents of the NKVD (People's Commissariat for Internal Affairs) sent to liquidate the dissident Marxist Unification Workers Party (POUM), which the Soviets accused of being an agent of fascism within the working class. The best-known Spanish victim would be POUM leader Andreu Nin, who was kidnapped in the Republican zone and murdered in June 1937. His corpse was never found. Up to a thousand other party members were also arrested, convicted, and imprisoned.
The reason for the anti-POUM campaign was that this communist party did not follow Comintern directives and had been publicly denouncing the Moscow Trials that led to the execution of Lev Kamenev, Grigory Zinoniev and other Bolsheviks. Additionally, Nin had invited Leon Trotsky to go to Barcelona while he was in exile in Norway. Trotsky settled in Mexico instead, where he was executed by a Stalinist agent in August 1940.
Nin's executioner was Lev Nikolsky, aka Alexander M. Orlov, a top NKVD agent. To this end, with Stalin's approval, he drew up a document in which he denounced an invented collaboration of the POUM leaders with the Falange, Franco, and their fascist allies. This was sent to the Republic's intelligence services and led to Nin’s being arrested in Barcelona. He was transferred from there to Valencia and finally to Madrid where, according to Boris Volodadarsky, Orlov managed to seize him and assassinate him, leaving false evidence of his alleged liberation by fascists.
The assassination of Andreu Nin was not the only one carried out by Orlov and other NKVD agents in the Republican zone during the war. Other victims included Austrian socialist Kurt Landau and one of Trotsky’s former secretaries. These deaths constitute a particularly sinister page of the intervention of the USSR in favour of the Spanish Republic at war.