From a review in The National Interest of two books by Paul Hollander on the violence and oppression of Communist states during the 20th Century (h/t, reader):
Communist terror varied from one country or region to another, and at different times within any one geographic unit; nevertheless, the common elements, both theoretical and practical, are easy to discern. Political police forces (known as “state security” organs), charged with controlling “ideological” rather than ordinary crime, tended to dehumanize the “class enemy” as historically obsolete and “destined” to become extinct. Abuse of the “mentally ill” designation also cut across communism’s manifestations.
Marx and Engels’ oxymoronic “dialectical materialism”, juxtaposing the inevitability of revolution with the imperative of party leadership and predicated on a quasi-divine belief in history as progress, allowed zealous disciples to justify terror and murder by transforming “is” into “ought.” Lenin understood perfectly that the next stage of history must be right, hence any means to bring it about were justified. Therefore, expediting the proletarian nirvana requires “eliminating” those who doubt the omnipotence, omniscience and benevolence of history’s anointed force, the vanguard of the proletariat, the Communist Party.
Not unexpectedly, as nirvana became more elusive, the number of concentration camp inmates grew. Their crimes were often simply accusations—or having been arrested. As the gap between reality and promise increased, so did the need to eliminate those most likely to notice. Repressive measures, including imprisonment and torture, were most frequently taken not against declared ideological opponents, but against members of an inherently “counterrevolutionary class.”
I think we understand that the atrocities and mass murders of communist states have been given a pass in history due to the reflexive sympathy to the Left's "the ends justify the means" ethic, on the part of the intelligentsia. I hope Hollander will help to undo that deception. Read the whole thing.