Conscription is back. After the Cold War, most European countries suspended mandatory military service, but now they’re rediscovering the institution that added muscle to the armed forces and some measure of social cohesion. The practice is often more a burden than an aid to the military. But with natural disasters and other emergencies increasing, what we really need is citizen resilience training.

“I can promise you one thing: We’ll have to discuss the issue of military service and national service very intensively again,”...