When did the campaign of political  repression that Mikhail Demichev was arrested during occur?
Great Purge The Great Purge or the Great Terror (Russian: Большо́й терро́р ) was a campaign of political repression in the Soviet Union which occurred from 1936 to 1938. It involved a large-scale purge of the Communist Party and government officials, repression of peasants and the Red Army leadership, widespread police surveillance, suspicion of "saboteurs", "counter-revolutionaries", imprisonment, and arbitrary executions. Mobile gas vans were invented to execute people without trial. In Russian historiography, the period of the most intense purge, 1937–1938, is called Yezhovshchina (Russian: Ежовщина ; literally, "Yezhov phenomenon", commonly translated as "times of Yezhov" or "doings of Yezhov"), after Nikolai Yezhov, the head of the Soviet secret police, the NKVD, who was later killed in the purge. It has been estimated that 600,000 people died at the hands of the Soviet government during the Purge.
Pyotr Demichev Pyotr Nilovich Demichev (Russian: Пётр Нилович Демичев ; 21 December [O.S. 3 January 1918] 1917 10 August 2010) was a Soviet-Russian political figure. He was First Deputy Chairman of the Presidium of the Supreme Soviet from 1986 to 1988 and Minister of Culture from 1974 to 1986. He was a deputy Politburo member beginning in 1964. He was considered to be a "Communist Party ideologist" with little sympathy for liberal movements within the Soviet Union.