What the Mafia has in common with protecting the Vatican from terror attacks

PBS NewsHour - Segments

During Christmastime at the Vatican, more visitors means added security, especially in the wake of terrorist attacks in Paris, London and many other European capitals. In recent days, ISIS has called on lone-wolf terrorists to shed "Christmas blood" at the Vatican. Special correspondent Christopher Livesay reports on what Italy learned about deterring terrorism from years of tracking the Mafia.