The NSA turned its eye on ordinary American citizens after 9/11, creating a massive surveillance dragnet to collect and monitor the communications of millions— without warrants, under a legal authority that hadn’t existed before.

As FRONTLINE explores in United States of Secrets: Part One, it was called “the program”— and when it came to light through Edward Snowden’s revelations, it sparked an intense debate over privacy, secrecy, and democracy in a post-9/11 world.

How did “the program” come to be? Why did the government keep it hidden from the people it was meant to protect? And what happened to the whistleblowers who spoke out against it?

Join us in a live chat with United States of Secrets: Part One producer and writer Mike Wiser and NSA whistleblower Kirk Wiebe, on Wednesday, May 14 at 2pm ET.

Spencer Ackerman, national security editor for the Guardian US, will serve as guest questioner.