Cass Sunstein is much much more than the bestselling author of the seminal book "Nudge" which changed the way that policy makers thought about policy - and one could argue if that was a good thing or a bad thing. Because, and this goes back to this conversation about the question of filter bubbles and echo chambers and the "#republic", Sunstein's new book: Who is the agent for change, politically, socially, economically? The election of Donald Trump upended a lot of things that were taken for granted about the way politics is done, about the way the public discourse is constructed. We have to rethink what this really means, says Sunstein. It is a democratic call to action.