(The Economist) – One of the worst dilemmas soldiers face is what to do when they confront armed children. International law and most military codes treat underage combatants mainly as innocent victims. They offer guidance on their legal rights and on how to interrogate and demobilise them. They have little to say about a soul-destroying question, which must typically be answered in a split second: when a kid points a Kalashnikov at you, do you shoot him? Last month Canada became the first country to incorporate a detailed answer into its military doctrine. If you must, it says, shoot first.