Back in December, when the White House first declared that any use of chemical weapons by the Syrian government would constitute a "red line" whose crossing would produce some kind of response (they never said what kind), I wondered why the taboo against chemical weapons exists. Now that it looks like we're about to start bombing Syria, it's worth revisiting the question of what lies behind the taboo and how it is guiding our feelings and actions.
Why do we have this international consensus saying that while it's bad for someone like Assad to bomb a neighborhood full of civilians and kill all the men, women, and children therein, it's worse for him to kill that same number of civilians by means of poison gas than by means of "conventional" munitions that merely tear their bodies to pieces? Indeed, we act as though killing, say, a hundred people with poison gas is worse than killing a thousand or ten thousand people with conventional weapons. After all, the Obama administration (not to mention the rest of the world) reacted to Assad murdering 100,000 people by expressing its deep consternation and trying to figure out how to help without getting involved. But only now that he has apparently used some kind of lethal gas in an attack that accounted for less than one percent of all the civilians he has killed are we finally ready to unleash our own military.
Part of the reason is that we set up this international norm almost a century ago after World War I, and in the years since it's been solidified with formal treaties like the Chemical Weapons Convention and a general, unquestioned consensus that chemical weapons are particularly awful. Nobody's out there making the case that it's OK to use them, and when they are used, the people responsible always deny it. It doesn't much matter whether the norm is perfectly rational; it exists, and it affects the decisions states and individuals make.
But the White House isn't saying they're obligated by the Chemical Weapons Convention to act against Assad's government. They're presenting it as a moral imperative, a product of our collective horror at what Assad did. Perhaps that's true, and Obama is taking action now not because he genuinely thinks Assad's latest war crime is worse than those that came before it. But the real issue is that he made this "red line" threat, and now he has to follow through on it lest he lose credibility. Either way the upcoming military action is a consequence of the chemical-weapon taboo. This isn't a repeat of Iraq, where "weapons of mass destruction" was a pretext to justify the invasion George W. Bush and his advisors so desperately wanted. It's pretty obvious that few in the administration are happy about this new campaign, but they feel they have little choice.
I'm skeptical, but ultimately agnostic, about whether in situations like this the taboo ends up doing more good than harm. On one hand, formal and informal prohibitions against certain kinds of weapons serve to make their use less likely and therefore reduce the death and destruction of war. On the other hand, you could argue that the taboo encourages the creation of "red lines" that, once violated by somebody, make escalation more likely. After all, we're about to enter into a military engagement in Syria because of the taboo against chemical weapons, and it's hardly impossible that that engagement could spin out of control and eventually increase the sum total of death and suffering.
Which brings us back to the question of why the use of certain kinds of weapons should be taboo in the first place. One reason would be that, like nuclear weapons, they kill enormous numbers of people indiscriminately. That isn't true of chemical weapons; they can kill many people at once, but so can conventional bombing. The taboo against the use of chemical weapons, furthermore, has never been solely about their use against civilians; the real widespread horror about them grew out of World War I (though it existed before), where they were used against soldiers. Another reason would be that they produce an unusual amount of suffering compared to other weapons. That isn't true of chemical weapons either. It would be horrific to die from poison gas, but getting your limbs severed by shrapnel and then bleeding to death wouldn't be any more pleasant.
And that brings me to one final point, a suggestion I'd like to make about the role of media and images in producing public revulsion and legitimizing military action. If you've watched the coverage of these events on television, you've no doubt heard the warnings from anchors: "The images we're about to show you are disturbing." And indeed they are, particularly the ones of children—a child being washed down in a dingy hospital while crying out in anguish, rows upon rows of dead children's bodies, and so on. But it's precisely because chemical weapons leave no visible injuries that these images can be shown. If the same number of children had been blown apart by bombs, you'd never see the pictures at all, because the editors would have considered them too gruesome to broadcast. And not having seen the images, we might be just a little less horrified.