I completed this book just as the Gaza War broke out in December 2008. After having experienced the Second Lebanon War as a civilian under fire, I had a sense of déjà vu during this latest war. As the bombing continued, it was soon obvious to nearly any observer that the Israeli Air Force might run out of military targets before Hamas threw in the towel. “Then what?” asked my 16-year-old daughter. “Do we start shelling civilians?”

Her question goes to the heart of this book, as contemporary warfare raises difficult dilemmas about fighting small armies whose soldiers wear no uniforms and who fight in and among civilian population centers. The question, Who do you bomb when there are no more military targets? increasingly occupies state armies as they fight asymmetric wars, but it is not very far from the one guerrillas have asked themselves for decades, namely, Who do you bomb when you cannot reach military targets?

I try to answer both questions by explaining how the idea of civilian vulnerability expands during asymmetric conflict to allow strikes that in traditional wars violate the principle of noncombatant immunity. In Gaza, for example, police officers were among the first targeted in the early days of the fighting. Since when are police officers armed combatants? What nation would want to expose itself to such havoc as comes from destroying the very mechanism that prevents chaos and anarchy?