Sometimes wars provide the questions that philosophy teachers like to debate. For example,
The IDF is considering directing artillery fire at the source of rocket launchings. [Israeli Defense Minister Ehud] Barak is expected to convene a discussion on the legality of this tactic, since the rockets are frequently fired from residential areas. — Jerusalem Post
For 20 points, if someone is trying to murder your family and stopping him makes it likely that you will hurt his family, should you allow him to kill your people in order to avoid killing his?
Does it matter if the people the murderer is hiding behind have chosen to be ruled by said murderer in a democratic election? Do they bear some responsibility?
What if the murderer specializes in murdering civilians and knows that you — lehavdil — believe that everything should be done to avoid hurting them, even by accident? And therefore the murderer chooses this strategy because it improves his chances to kill your people with impunity?
Does it matter that the murderer will be fully warned and can stop the violence at any time?
Finally, although you will be the proximate cause of hurting or killing his people, since he has deliberately chosen this form of warfare, does not a large portion — perhaps all — of the responsibility for this fall on him?
In your essay, make sure to touch on the goals of both parties — the murderer, to commit genocide, and you, to live in peace.