The liberation of Auschwitz did not mark the end of the Holocaust—gassings continued until the eve of Hitler’s suicide on April 30, 1945, and thousands more died of the effects of starvation and mistreatment at places like Belsen even weeks after their liberation.

But the date of liberation, Jan. 27, should put us in mind of the beginnings. How did this happen? In particular, how could Germany, by all outward indications a civilized and modern country, become a persecuting society, brutally indifferent to the fates of anyone outside its supposed “people’s community”?

These questions should worry people for all time.