According to political scientist Carol M. Swain's unsettling new book, "The New White Nationalism in America: Its Challenge to Integration," the U.S. is on the brink of an explosion of white "tribalism" that could trigger unprecedented levels of racial antagonism and an epidemic of violence. The underlying cause: a swelling "white nationalist" movement fueled by simmering resentment of affirmative action programs like those used by the University of Michigan. "The book is a wake-up call to warn people that we're following a dangerous course by pushing identity politics and multi-culturalism," explains the Vanderbilt law school professor. "There's nothing special about...