The Secret Service has announced the departure of three employees connected to a prostitution scandal involving members of President Obama’s security detail. Eight others remain under investigation. The incident has focused attention on the training and oversight of Secret Service agents. It’s also damaged the agency’s reputation as an elite federal law enforcement team. After meeting with Secret Service Director Mark Sullivan, Senator Susan Collins asked whether there was evidence of other misconduct — and if the incident indicates a larger problem in the agency. Diane and her guests discuss the culture of the Secret Service.