The public optimism that came with the launch of social media a decade ago has settled into a wariness that we might instead face a long, grueling daily fight for truth and facts in the face of unrelenting, automated disinformation online. As the 2020 elections gear up, how should our country face the threat from Twitter bots and Facebook trolls? What responsibility should the government have to police the truth — and what role should the tech platforms play? What's the line between free speech, personal opinion — from anti-vaxxers to white supremacists — and disinformation?