Communist Party of Germany

Tschemerinski’s wartime experiences radicalized his political sympathies towards the Spartakusbund. Upon resuming his studies, he befriended Paul Levi and Ruth Fischer, who convinced him to join the Communist Party of Germany (KPD). He changed his name to Arkadi Maslow, and in November 1920 was elected to the KPD Central Committee. From 1921 Maslow, together with Ruth Fischer, led the left wing of the Berlin KPD. In 1921, Maslow became the foreign affairs editor of the Rote Fahne. Taken into custody by the Berlin police in 1922, he identified himself as a Soviet agent and a confidant of Leon Trotsky and Karl Radek. Because his passport had expired, he was sentenced to eight months in prison. To avoid serving prison term, he went into hiding. At the same time, a rumor circulated in the KPD that Maslow was a spy for the police. During a visit to Moscow in 1923, he was interrogated about these charges by an investigative committee of the Comintern, who exonerated and released him. However he remained under detention in Moscow until early 1924.

In April 1924, Maslow and Fischer, criticized as “right-wing” by August Thalheimer and Heinrich Brandler, assumed leadership of the Party and were responsible for intensifying the “left-turn” of the KPD. Taken once again into custody in May 1925, Maslow, together with Paul Schlecht and Anton Grylewicz, was brought to court and sentenced to four years in prison. Because of his failing health, Maslow was released in July 1926. Since Maslow and Fischer no longer enjoyed the protection of Grigory Zinoviev, under a directive of Joseph Stalin to favor Ernst Thälmann, they were relieved of the Party leadership, and on August 20, 1926, were excluded from the KPD.

Leninbund

Together with Ruth Fischer and Hugo Urbahns, Maslow brought together former members of the left wing of the KPD, which led to formation of the Leninbund in early 1928. The KPD thereupon accused Maslow of being an “Agent for the Bourgeoisie” and demanded that he not be allowed to leave Germany, under the supposition that his political work would then undermine the work of the KPD. In May 1928, Maslow and Fischer resigned from the Leninbund, because they disagreed with the Leninbund’s support of an independent candidate opposed to the KPD, and after the capitulation of Zinoviev and Kamenev who were opposed to Stalin, anticipated the hope (in vain) of being accepted again into the KPD. Until 1933, Maslow remained active as a translator and withdrew from extensive participation in political activity.

Exile

Following the rise to power of the Nazis in 1933, Maslow and Fischer first fled to Paris, where they resided until 1940. From 1934 to 1936, Maslow worked closely with Trotsky and served as a part of the movement towards a Fourth International. After the break with Trotsky, Maslow and Ruth Fischer founded a circle with the name Marxist–Leninist International Group, which lasted until 1939. During the Moscow Trials of 1936 to 1938, Maslow was again accused by the Stalinist press as an espionage agent.