As you report, riot-control technology is all the rage nowadays (“The Sound and the Fury,” August 13, 2011). Quelling unrest has become a lucrative trade around the globe. Experiences from different countries are being compared and new approaches to riot control spawned. After all, ochlocracy—the rule of the mob—is of ancient vintage. As you mention, Rome was often shaken by riots, which sometimes endangered the emperor and the senate. The Praetorian Guard used cavalry and swords against stone throwers. Indeed, the gear worn by policemen controlling riots is ever more reminiscent of that worn by the old Praetorians. Which rises an interesting possibility, though. During the long decline of the Roman empire, the Praetorians challenged the emperor and the senate on numerous occasions. And increasingly often. They themselves descended into the looting mob only to be cajoled back to their barracks by their supposed bosses with ever-larger donations. By and by, no-one was safe from them. The long decline of the European Union offers many interesting possibilities to the new Praetorians, no doubt.