Earlier this year, a defense contractor named Edward Snowden leaked classified documents to a small group of reporters about the National Security Agency’s top-secret surveillance programs. The information he provided has given the public an unprecedented view of the scope and cost of those programs.

Unlike most leakers, Snowden chose to go public. Federal prosecutors have charged Snowden with espionage and theft of government property. Snowden is now in Moscow, where he has temporary asylum.

Ben Wizner, an attorney for the ACLU, is coordinating Snowden’s legal defense. We spoke with him at his office in New York about the value and limits of leaks.

Sam Ward is a senior digital producer for Reveal, where he oversees the web team. He has years of experience producing creative digital media projects for Oregon Public Broadcasting, PBS, ITVS and the Smithsonian, and he has managed projects for funders such as the National Science Foundation, U.S. Department of Education and Annenberg Media. He graduated from Carnegie Mellon University in Pittsburgh. Ward is based in Reveal's Emeryville, California, office.