It's hardly a mystery why French economist Thomas Piketty's Capital in the 21st Century has generated so much intellectual excitement here in the United States. The subject of the book, economic inequality, has become in recent years a major fault line in American ideological and partisan conflict. President Barack Obama, for his part, has called it "the defining challenge of our time." Yet as Brink Lindsey explains, Piketty and his American admirers are guilty of performing an intellectual sleight of hand. Don't be fooled.