Guest: Edward J. Watts is Alkiviadis Vassiliadis Endowed Chair and Professor of History at the University of California, San Diego. He is the author of Mortal Republic: How Rome Fell into Tyranny, The Final Pagan Generation, Hypatia: The Life and Legend of an Ancient Philosopher, and his latest, The Eternal Decline and Fall of Rome: The History of a Dangerous Idea.