Throughout history, the state has justified itself on the grounds that it is necessary to protect us from others whose habits and beliefs — we are meant to believe — are dangerous. For millennia, this fiction was easy to maintain because most people interacted so little with people outside their nearly autarkic — and therefore impoverished — communities. But, with the rise of industrialization and international trade in recent centuries, the state's claim that it is necessary to keep us “safe” from outsiders has become increasingly undermined. Much of this is thanks to the fact that in order...