Even if you use the Taliban's inflated numbers and the Taliban sticks around until next spring, we'll still have plenty left on the balance sheet for when we move beyond Afghanistan.

I would go beyond that. There should be some discount factor to account for deliberate murder of civilians vs accidental casualties in waging legitimate war. Such a factor would also account for the unknowable numbers of future civilians saved by rooting out the infection as soon as possible. I'm not sure what the discount rate should be, but even if tens of thousands of civilians die collaterally (though I think that unlikely and unnecessary, unless it's because the scum choose to hide behind the skirts of their women and children, as Saddam did), it might be acceptable to prevent the deaths of hundreds of thousands, both in the West and in the Mideast, in the absence of such necessary action.

Anyway, as Professor Reynolds noted yesterday, Mary Robinson's definition of proportionality (no civilian casualties) truly is a prescription for no war at all, which is tantamount to utter defeat for civilization.