The Book of Esther provides one possible answer to that question, tough cookie though it is. Today, that query may not loom quite as large in America, but it definitely does in many other places throughout the world (the Middle East, Burma, the Congo—and about a dozen or more other places). It happened to loom really large in the ancient Middle East too. In Esther's case, though, no one seems to know if there really was a wicked counselor named Haman who attempted to manipulate the emperor (probably Xerxes I, though here he's called "Ahasuerus") into having all the Jews in the Persian Empire murdered during the fifth century BCE. Nevertheless, you don't have to look too deeply into Jewish history to find highly similar attempts at genocide and persecution against the Jews. The story (which was probably written during the third or fourth Century BCE) may have helped people who were living under later rulers and needed to reckon with threats from above (regardless of how historically accurate the story is—or isn't).