The USSR sent weapons to the Stalinist faction in the Spanish Republic, hoping after the war they would become a puppet state.
The efforts of the Anarchists during the war (establishing stateless, horizontal power structures) were undermining that effort, thus the Stalinists turned on them (and the anti-stalinist Marxist faction) mid-war, calling them ‘secret fascists’ helping the enemy, and proceeded to round them up for execution.
The USSR sent weapons to the Stalinist faction in the Spanish Republic, hoping after the war they would become a puppet state.
The efforts of the Anarchists during the war (establishing stateless, horizontal power structures) were undermining that effort, thus the Stalinists turned on them (and the anti-stalinist Marxist faction) mid-war, calling them ‘secret fascists’ helping the enemy, and proceeded to round them up for execution.