AP Photo

Seventy years ago today the two most vile systems the world has yet produced locked themselves in a deadly embrace. Along an 1,800-mile front, 4.5 million soldiers of Hitler’s Nazi Germany and its allies commenced Operation Barbarossa, launching themselves against Stalin’s Communist regime. At the time, not many gave the Soviet Union much chance of survival, and the results of the first few months of fighting seemed to bear out those estimations.

By early December, German forces had surrounded Leningrad and pushed deep into...