Twenty-two years ago, historian Daniel Jonah Goldhagen overturned the applecart in Holocaust studies, arguing provocatively in his book Hitler’s Willing Executioners that the German people participated avidly in the Nazis’ systematic slaughter of their Jewish countrymen.

Goldhagen’s thesis, which fueled a fiery debate over the responsibility of everyday Germans for the Holocaust, now has an Italian analogue, as Simon Levis Sullam contends in a new book that thousands of members of the fascist regime—from ideologists to carabinieri to desk clerks—actively took part in the genocide of Italy’s Jewish population.