For former hotel manager Paul Rusesabagina, words are the most powerful weapon in the human arsenal. For good and for evil, as was the case in the spring of 1994 in Rwanda. Over 100 days, some 800,000 people were slaughtered, most hacked to death by machete. Rusesabagina—inspiration for the movie Hotel Rwanda—used his facility with words and persuasion to save 1,268 of his fellow countrymen...