When the public can not agree upon a shared reality—when confusion and distrust and propaganda reign—politics devolves into a pre-democratic struggle for power, which will disfavor resisters. Donald Trump may not understand this dynamic academically, but it was a hallmark of his campaign and has become a hallmark of his pre-presidency. Sometimes his false pronouncements are buffoonish and ill-considered, but make no mistake: he is taking a hammer to one of liberal society’s guardrails. Dartmouth College Political Scientist Brendan Nyhan has studied the ways information and disinformation affect political processes extensively. He joins New Republic Senior Editor Brian Beutler to explore why propaganda and conspiracy theory are so prevalent today, how this plays neatly into Trump’s hands, and what can be done about it.