Riots in black ghettos. Rebellions on campus. The news these past few months, and particularly in the past week, has been full of stories that remind us, as William Faulkner wrote a little more than half a century after the Civil War, that “the past is not really dead, it is not even past.”

We’re seeing something that looks eerily like a recurrence of events half a century ago that led to the destruction of American cities and campuses.