Founding Father James Madison would be horrified to see how social media has helped unleash populist passions and accelerate public discourse. Madison and other founders created a representative republic rather than a direct democracy, designed to slow down deliberation so that majorities could rule based on reason rather than passion. But Jeffrey Rosen, president and CEO of the National Constitution Center, says social media technologies have created the very mobs, demagogues, echo chambers, and factions that Madison feared. He speaks with Jeffrey Goldberg, editor in chief of The Atlantic about how social media is threatening the America idea.