The fallout from Supreme Court Justice Antonin Scalia’s death is being felt on the campaign trail. One of the most controversial decisions he backed was Citizens United, the 2010 case that gave corporations and unions unlimited spending power in political campaigns. This is expected to be the most expensive presidential race in history. Candidates on both sides are talking about campaign finance reform. But do they have any real power to make changes? We hear from the author of a new book on money in politics.