On the last day of April, a federal appeals court in Cincinnati provided what we must hope is the final word on John Demjanjuk. After a series of court actions spanning 29 years, a three-member panel decided he was indeed the Ukrainian-born prison guard known as "Ivan the Terrible"; at the Nazis' Treblinka death camp, in Poland. The judgment leaves Demjanjuk, now 84, certain to be stripped of his fraudulently obtained U.S. citizenship. By cruel coincidence, the court's ruling came the same day we learned that fellow Americans are capable of conduct as reprehensible as many Nazis, that war itself...