Words kill as surely as bullets, says Adama Dieng, the United Nations Special Adviser on the Prevention of Genocide. Bringing a historical perspective to current trends, he examines the roots of the problem and offers potential solutions that focus on the world’s youth. Mr. Dieng was central to the development of the United Nations Strategy and Plan of Action on Hate Speech, which contains ideas on how to address the root causes and drivers of hate speech and how to reduce its impact on societies.