In his essay for the Knight Institute's Emerging Threats series, Columbia Law School's Tim Wu observes that some of the forces undermining contemporary political discourse — such as “troll armies,” “flooding,” and propaganda robots — may be beyond the reach of traditional free speech protections. In a conversation co-hosted by the Knight Institute and the Brown Institute at Columbia Journalism School, Tim Wu, Julia Angwin from ProPublica, and Columbia Law Professor and Knight Institute Visiting Scholar David Pozen explore how to respond to these new threats.