During that time, Joseph Stalin’s purges of Leon Trotsky and the left opposition in the Communist Party of the Soviet Union (CPSU) were at their height. Larsen became a member of the CPSU and sided with the opposition to Stalin. Larsen was prompted for a repudiation of his previous views after Stalin’s victory at the 1927 party congress and the subsequent banishment of Trotsky to Alma Ata, but it was only after severe pressure that he complied. However, the repudiation did not prevent Larsen from being expelled from the International Lenin School in April 1928 and banished to Nizhny Novgorod.