For decades, billionaire libertarians Charles and David Koch have spent millions trying to reduce the size of government and slash regulations, making the brothers a target of the political Left and campaign finance reformers. But few people have dug deeper into the Koch empire and family history than New Yorker staff writer Jane Mayer, author of the new book "Dark Money." Among other revelations, she alleges that the brothers hired private detectives to investigate her after she published articles critical of them. We talk to Mayer about the book and about what the rise of Donald Trump means for the Kochs and their allies.