One argument against the comparison I'm drawing is obvious: We, unlike Bin Laden, never deliver a bomb with the intention of killing a civilian. That's a valid distinction. Still, Donald Rumsfeld has said that some collateral damage is bound to happen. So, like Bin Laden, we launched a war knowing that it entailed civilian deaths; the deaths were inseparable from a strategy justified by a goal we deemed good, so we proceeded to cause them.
Another argument against my comparison is also obvious. Actually, it isn't an argument so much as a label. The claim would be that I'm positing "moral equivalence" between George Bush and Osama Bin Laden. This phrase (like the charge of "appeasement," which is also getting applied to critics of this war) is basically designed to end rational discussion.
Let me pre-emptively strike at this pre-emptive strike by mentioning just one of the various senses in which there isn't moral equivalence between George W. Bush and Osama Bin Laden. The war in Afghanistan comes in retaliation for the murder of thousands of people—murder not just in the eyes of almost every thinking person on the planet, but in the eyes of international law. Osama Bin Laden can't make the same claim about the American behavior that led to his "retaliation."
Still, as we conduct a war that is in principle morally defensible (even if, as I argued before it began, it could well prove counterproductive), let's at least try to keep it defensible in practice.
Maybe the best way to make my point is by historical perspective. For most of human history, most peoples have believed in the very steep discounting of foreign lives. Aristotle, according to Plutarch, advised Alexander the Great to treat non-Greeks "as though they were plants or animals." Two thousand years after this advice was given, Europeans were still treating some foreigners—native Americans, for example—as though they were plants or animals.
In the modern world, we don't talk the way Aristotle did. America is a morally universalistic nation, believing that all people, regardless of race, creed, or nationality, are human beings and deserve respect. (This belief, embedded in the logic of global commerce, is perhaps the strongest defense of globalization.) Osama Bin Laden doesn't share this belief. He massively devalues people's lives based on their religion, or on their residing in a country whose government he dislikes. He is a relic of a primitive moral age that humanity, after scores of millenniums, has finally started to crawl out of.
This is fundamentally what we're fighting about: moral universalism, the idea that no person, by virtue of religion or race or nationality, is better than any other person; the idea that casually devaluing people's lives in the pursuit of your political goals is wrong. At least, that is the claim I'd make on our behalf. But the higher the number of dead Afghan civilians—and the higher the ratio of that number to the number of dead American soldiers—the less plausible the claim, and the closer we come to being the moral equivalent of Osama Bin Laden. That we'll never get all the way there strikes me as meager consolation.