Not long after my 10th birthday, early in 1987, my teacher walked into class one morning and asked us to march, single file, to the gymnasium. There, on a wood-paneled television, we watched as a ruddy-faced man was led into a courtroom. We were soon to witness, she said, a trial we would remember for the rest of our lives.

You can forgive my teacher her hyperbole. John (Ivan) Demjanjuk stood accused of being Ivan the Terrible, the fright of Treblinka, a sadistic guard who would torture Jews with his whip and his sword before...