Stalin was the General Secretary of the Communist Party of the Soviet Union's from 1922 until his death in 1953. In the years following Lenin's death in 1924, he became leader of the Soviet Union and the ComIntern.

One cannot have been a communist in Europe in these times without being in an active supporter of Stalin. The ComIntern and essentially all European communist parties were under strict control of Moscow/Stalin. Those who opposed Stalin typically faced a violent end.

Of course after Stalin's death and the concommitant weakening of communist power, most communists active during Stalin's times lied about their involvement.