Since the assassination of JFK, the United States Secret Service has stepped up its mission to protect the president and others. But as described by Pulitzer Prize-winning reporter Carol Leonnig in her new book, "Zero Fail," the USSS is an agency reluctant to examine its operational failures, jeopardizing the Secret Service's mission. Correspondent Jim Axelrod talks with Leonnig; former agent Jonathan Wackrow, who served 14 years with the Secret Service; and former Homeland Security Secretary Michael Chertoff, about the challenges facing the Service, including a major one: transparency. Air Date: May 16, 2021