in Trotsky's letters. It is known that Vissaron Lominadze formed an underground group, called by some "the Left-Right bloc" to oppose Stalin's policy of collectivization. Historical analysis In the Moscow trials, the defendants were found guilty of conspiring against Stalin, of having formed a conspiratorial bloc and collaborated with foreign governments. When it was discovered that Trotsky had indeed formed a "bloc" with the opposition in the USSR, like the Soviet government claimed, it put the Trials in a new light. Most historians at the time believed that they were nothing but a campaign to destroy anyone in the party who disagreed with Stalin, but it was clear that it was based on this bloc, albeit exaggeratedly. Trotsky's letters did not contain any evidence of collaboration with foreign powers nor that Trotsky approved of a 'terrorist policy'. Broué concluded the bloc ceased to exist by early 1933, because some of its members, like I.N. Smirnov, Ryutin and the leaders of the Eismont group were arrested and Zinoviev and Kamenev had re-joined the party. Broué later noted that, even imprisoned, several opposition members continued participating in an underground Trotskyist group. In early 2018, some documents belonging to this group were discovered by the Russian Federal Prison service in the Verkhne-Uralsk isolator, where certain opposition leaders, like Alexander Slepkov were imprisoned. Many things are still unknown about the bloc. Mainly because some letters in the Trotsky Letter Archives were missing. The ones that were left had some words 'carefully erased' and one was cut with scissors. Broué and Getty concluded that the missing letters were most likely removed or destroyed. References 1932 establishments in the Soviet Union 1933 disestablishments in the Soviet Union Factions in the Communist Party of the Soviet Union Marxism Trotskyism in Russia Leon Trotsky Bolsheviks Soviet opposition groups Anti-Stalinist left