The author defines genocide, noting that domestic genocide arises in pluralistic societies as differences between groups such as economic, religious, ethnic, or political differences that enable these groups to polarize. Two elements in cultural pluralism are examined in detail. The first is drawn from the theory that dehumanization generally precedes and is a necessary precondition of genocide. The second concerns the motivating force of ideologies, that which gives the genocide its primary significance. Numerous historical events are cited to illustrate each of these concepts. In fact, these two elements often are intermingled in instances of genocide. History has shown that derogatory dichotomies are not a necessary precondition to a genocidal threat. Likewise, animosity and polarization between groups may exist for long periods without any threat of annihilative violence. It appears that persecution, expulsion, and massacre often can be sudden and unpredictable. 18 references.