Benjamin A. Valentino finds that ethnic hatreds or discrimination, undemocratic systems of government, and dysfunctions in society play a much smaller role in mass killing and genocide than is commonly assumed. He shows that the impetus for mass killing usually originates from a relatively small group of powerful leaders and is often carried out without the active support of broader society. Mass killing, in his view, is a brutal political or military strategy designed to accomplish leaders' most important objectives, counter threats to their power, and solve their most difficult...