How the Iraq body count project is counting Fallujah

Just a quick reminder for readers who've been off-planet for the last three years. Some time around the end of 2001 almost three thousand US citizens were murdered by terrorists, mainly from Saudi Arabia and with support from factions based in Afghanistan.

At this point, the US decided it had the right to unilaterally take pre-emptive action against any state that it decided was "supporting terrorism" or which "bred" or "tolerated" terrorism. (This pretty much covers any arabic or islamic state, given that all such states at least have connections with groups who are anti-Israel, and may be channeling money into the Palestinian resistance movement.)

Under this new rubric, and based on some false intelligence which they clearly weren't keen to question too much, the US (unfortunately supported by my own country, the UK) decided to invade Iraq. They declared victory after a short war which succesfully removed Saddam Hussain from power. But the politicians and planners were clearly unprepared for the realities of rebuilding the country. Worse, they appear to have been so blinded by their own self-righteous victim-hood that they either failed to forsee, or simply discounted the legitimacy of, any resentment this would inspire. And these lapses have allowed a swarm of semi-independent resistence movements to form, and the country seems to be bogged down in a guerrilla war.

At the point of writing (November 27th, 2004), according to the fairly conservatively calculated Iraq Body Count project - which counts civilian casualties according to an averaging of media reports - the number of Iraqi civilian casualties is around 15,000.

In other words, the current US (over) reaction is an escalation of 5:1.

So here's the question for anyone who still supports the war in Iraq on the grounds it's justified to protect the US against terrorism. If you're allowed a 5:1 escalation ie. it's OK to kill 15,000 of their innocents to protect 3,000 of yours. Are they allowed to do the same thing? Is (say) Iran justified in killing 75,000 US civilians pre-emptively if it thinks this will protect it from a similar fate (and loss of civilians) that Iraq suffered?

And, if not, why not?

I'm not asking if such an Iranian attack is possible or practical. After all, the invasion of Iraq probably hasn't made the US much safer. But assuming that this was a plausible hypothesis at some point, and that this 5:1 escalation was seen as justified, is a 5:1 escalation by Iran also justified?