A Presidential Debate or a Comment Thread Come to Life?

There was never a golden age of American political discourse, but the 2016 Presidential-primary debates were a bruising low point. The shouting without substance, the crude insults and references to hand size, looked more like an argument in an online comments thread than an informed contest of ideas for the highest office in the land. What can we expect from the three Clinton-Trump debates? Jill Lepore explores how technological changes alter the way we argue, and examines the history of debate broadcasts, including how a clever foe of F.D.R. faked a debate by recording his own responses to spliced-together bits of Roosevelt’s speeches.