Philosophy in the Soviet Union was officially confined to Marxist–Leninist thinking, which theoretically was the basis of objective and ultimate philosophical truth. During the 1920s and 1930s, other tendencies of Russian thought were repressed (many philosophers emigrated, others were expelled). Joseph Stalin enacted a decree in 1931 identifying dialectical materialism with Marxism–Leninism, making it the official philosophy which would be enforced in all Communist states and, through the Comintern, in most Communist parties. Following the traditional use in the Second International, opponents would be labeled as "revisionists".