Perhaps the only thing that outrages Russian defenders of Stalin more than the obvious parallels between his regime and Hitler’s is any reference to the alliance the two dictators formed in 1939 with the Molotov-Ribbentrop Pact, one that opened the way to war in Europe and lasted until Hitler turned on his former ally in June 1941. But now there may be something even more offensive to such defenders of Stalin and his system: the discovery of documents which confirm that the NKVD cooperated closely with the Gestapo well before the Molotov-Ribbentrop Pact was signed and that may have paved...