Fred Clark did a magnificent drash on Ursula K. LeGuin's classic short story "The Ones Who Walk Away From Omelas" (text file) in a series of three blog posts, put up on (and between) the anniversaries of the bombings of Hiroshima and Nagasaki. I recommend you read LeGuin's story if you haven't previously done so -- it's fabulous anyway, and I'd recommend it regardless of the commentary -- and then read Clark's series:
Greetings from Omelas
There's also a postscript, "Sez Who", here, which is not as central to the rest of the series.
*"YNATKC" is an acronym -- of Clark's devising, so far as I know -- for "You're not allowed to kill civilians", and point he's made repeatedly (although, as I suspect he'd agree, it's a point that can never be made sufficiently here in Omelas).