there was an interesting piece in the NYRB recently that I found interesting. Here's the kernel of the argument:
"Auschwitz is only an introduction to the Holocaust, the Holocaust only a suggestion of Hitler's final aims. Grossman's novels Forever Flowing and Life and Fate daringly recount both Nazi and Soviet terror, and remind us that even a full characterization of German policies of mass killing is incomplete as a history of atrocity in mid-century Europe. It omits the state that Hitler was chiefly concerned to destroy, the other state that killed Europeans en masse in the middle of the century: the Soviet Union. In the entire Stalinist period, between 1928 and 1953, Soviet policies killed, in a conservative estimate, well over five million Europeans. Thus when one considers the total number of European civilians killed by totalitarian powers in the middle of the twentieth century, one should have in mind three groups of roughly equal size: Jews killed by Germans, non-Jews killed by Germans, and Soviet citizens killed by the Soviet state. As a general rule, the German regime killed civilians who were not German citizens, whereas the Soviet regime chiefly killed civilians who were Soviet citizens. "
from "Holocaust: The Ignored Reality" http://www.nybooks.com/articles/22875