democracynow.org: "At this stage I can offer nothing more than my word. I am a senior government employee in the intelligence community. I hope you understand that contacting you is extremely high risk … This will not be a waste of your time.” This was one of the first messages Edward Snowden wrote to filmmaker Laura Poitras beginning an exchange that helped expose the massive surveillance apparatus set up by the National Security Agency. Months later, Poitras would meet Snowden for the first time in a Hong Kong hotel room. Poitras filmed more than 20 hours of footage as Snowden debriefed reporters Glenn Greenwald and Ewen MacAskill. That footage — most unseen until now — forms the backbone of Poitras’ new film, “Citizenfour.” She joins us to talk about the film and her own experience with government surveillance. The film is the third installment of her 9/11 trilogy that also includes “My Country, My Country” about the Iraq War and “The Oath” about the U.S. military base at Guantánamo Bay, Cuba. Poitras’ NSA reporting contributed to a Pulitzer Prize for Public Service awarded to The Guardian and The Washington Post.