Threatened self-esteem accounts for a large portion of violence at the individual level, but to really get a mass atrocity going you need idealism—the belief that your violence is a means to a moral end. The major atrocities of the twentieth century were carried out largely either by men who thought they were creating a utopia or else by men who believed they were defending their homeland or tribe from attack.30 Idealism easily becomes dangerous because it brings with it, almost inevitably, the belief that the ends justify the means.
