To date, more than 100,000 Syrians have been killed in that nation’s bloody civil war, but not until the Syrian government’s apparent use of chemical weapons did the United States seriously start to debate intervening. The people killed by chemical weapons (estimates range from the hundreds to more than a thousand) are just a tiny fraction of the UN’s estimate of the total death toll, and a question has understandably arisen: Why are chemical weapons so different? Of all the horrors of conflict, all the ways victims have been killed, why should chemical weapons be singled out as such a critical marker of barbarity?
The worldwide taboo against chemical weapons is more than a century old, encompassing both formal international prohibitions and widespread public opinion—the sense, even among people who can't explain what they are, that chemical weapons are particularly egregious. It has been ascribed to a number of causes—the human revulsion against poisons; the indiscriminacy of the technology; even, surprisingly, the notion that they are ineffective—but none of them tells the whole story by itself.
Countless new weapons introduced in the history of warfare, from the crossbow to firearms to drones today, have met with their share of condemnation as unfair and immoral. And in nearly every case, this initial condemnation has slowly turned to acquiescence as the new contrivance is grudgingly accepted as part of the "conventional" armory humanity has to endure when conflict erupts.
Not so with chemical weapons. The taboo was broken more than it was honored early on, but today stands out as one of the most successful efforts to curtail the horrors of war. The combination over time of moral argument, repeated international agreements, some fortunate timing, and—perhaps most important—a tradition of nonuse, have by now endowed chemical weapons with an almost unique status. And looking at how it came about has lessons for how violence-prevention measures have and might in future take hold.
Various rudimentary forms of what could be called chemical weapons, like the use of choking smoke in sieges, always dotted the face of war. But it wasn't until the 20th century's combination of industrialized warfare and chemical science that the systematic use of poison gas arrived on the battlefield.
By the time it did, in World War I, it was already technically against the rules. The Hague Declaration of 1899, an important treaty to codify the laws of modern warfare, had banned gas shells when such weapons were still just a potential threat. Poisoning soldiers had long been considered an illegitimate tactic in battle, and chemical weapons seemed broadly to fall in this category. But delegates to the Hague Conference didn't seem to place an inordinate amount of importance on the topic: It was a weapon that had not even been developed, so nations were not giving up anything yet of importance.
The ban was obliterated in World War I, and accusations of who violated the Hague Declaration were traded as part of the war of propaganda. In 1915, the Germans began placing cylinders filled with toxic chlorine gas along the front, then opening them when wind conditions were favorable. Eventually both sides in the conflict were firing shells filled with chemical agents like mustard gas and phosgene.
The shock of being attacked via this new method of destruction was memorably captured in the war poet Wilfred Owen's "Dulce et Decorum Est":
...someone still was yelling out and stumbling,
And flound'ring like a man in fire or lime.
Dim, through the misty panes and thick green light,
As under a green sea, I saw him drowning.
In all my dreams, before my helpless sight,
He plunges at me, guttering, choking, drowning...
The scale of use was astonishing: By the end of the war, it has been estimated that as much as one-third of munitions were chemical weapons. Over time, rudimentary gas masks provided some protection against the attacks, and gas seemed to be taking its place as one of a number of that war's daunting innovations, including the tank and aircraft. Not everyone singled out gas at the time as uniquely the worst of these innovations, and indeed one US veterans organization argued in favor of chemicals as offering the future prospect of more humane warfare, where victims were temporarily disabled but then could potentially recover intact, unlike those who suffered the egregious wounds of bayonets and disfigurements of shellfire.
But gas was also less discriminate than bullets or shells; depending on the wind, it could spread beyond battle lines. In the early 1920s, the specter of devastation against civilian populations in future wars—especially as air power increased—made chemical weapons an ongoing source of concern to the public. Lobbyists for the chemical industry, as well as government chemical-warfare departments in the United States and United Kingdom, also stoked public fears about German gas attacks—an effort to boost support that backfired by contributing further to general anxiety. Spurred by this worry, nations embarked on a series of initiatives that culminated in the Geneva Protocol of 1925, which for most of the 20th century stood as the key international treaty prohibiting use of chemical weapons.
The path to the 1925 agreement was smoothed by the fact that many felt it wasn't really committing states to anything meaningfully new, nor likely something that would particularly work, given the "chemical war" of WWI. And not every major power signed it: The United States would not adopt the Geneva Protocol for decades. But as modest as those beginnings were, they were also special. The usual restrictions in treaties govern how a weapon is to be used; the prohibition against chemical weapons was, at least in the language of the treaty, absolute and universal. Since then, this sense of a bright line has helped the cause of various moral entrepreneurs—including US President Franklin Roosevelt—in keeping alive the antipathy toward chemical weapons.
Over the course of the 20th century, something interesting happened: The very act of restraint—especially the fact that World War II did not become a widespread chemical war—further forestalled the usual process of humanity grudgingly "getting used to" another regrettable military horror. Politically, the fact that even Hitler did not unleash chemicals as a weapon of combat (despite using gas on a massive scale in extermination camps) served to further cast the use of chemical weapons as something aberrant and inhuman.
This tradition of nonuse has proven critically important, especially the restraint on both sides in WWII. It was a combination of several factors—the deterrent effect of possible retaliation in kind, a fear on both sides of not being prepared to press and hold an advantage, and some luck of circumstance. It is entirely possible, for example, that the British would have used chemicals against a German invasion had the channel been crossed. Had the US war in the Pacific gone on longer, at continued awful human cost, US chemical restraint might well have given way, since Truman did not exhibit Roosevelt's committed personal antipathy against the weapons. It has also been alleged that Hitler gave the order to use chemicals towards the close of the war, but his generals refused to implement the order. The maintenance of the taboo was very precarious indeed.
Today, it is sometimes argued that chemical weapons can't possibly be effective weapons of war, since nations would surely only agree to give up weapons that they didn't really have use for anyway. But that kind of post-facto rationalization does not stand up to the historical record. Post World War I British military studies concluded gas had indeed been effective; a study by the United States during World War II concluded that gas would be the most effective weapon against Japanese cave and tunnel defenses in the Pacific. And in the 1980s Saddam Hussein turned to chemical weapons quite effectively to help blunt the Iranian human wave attacks that had appeared to put Iraq on the brink of defeat.
The Chemical Weapons Convention of 1993 would eventually extend the ban to production, trade, and even possession. The United States, which was a party to the Hague Convention but took 50 years to ratify the Geneva Protocol, ratified the treaty and has now destroyed nearly its entire chemical stockpile. (Syria is a party to the Geneva Protocol, but never ratified the 1993 treaty.)
Over time, the persistence of the chemical-weapon taboo has contributed to further restraint—most notably, the successful effort to ban antipersonnel land mines in the 1990s. If militaries around the world had successfully obeyed their civilian decision makers and curtailed the use of one indiscriminate weapon, then getting rid of another was not so fanciful or idealistic a proposition. Without the chemical weapons precedent, the diplomats pressing the anti-land-mine cause would have had a much, much tougher path.
Today, it is easy to look at the deaths in Syria and bemoan the flimsiness of international law. But if anything, what's happening in Syria reveals a taboo that is on balance being reinforced—far from defending the use of chemicals as acceptable, the Syrian regime and rebels have denied their use. (Contrast the Bush administration's defenses of waterboarding, which many feel weakened the modern taboo against torture.)
Scholars have found that a key in trying to assess the power or weakness of international norms is the reaction when they are violated, and in this regard the chemical ban appears strong. In recent weeks, many governments around the world have vociferously condemned the Assad regime's chemical attacks, even if they haven't made the moves the United States has toward punishment by force. No would-be future user of chemicals could possibly conclude that such use will simply be tolerated.
The Syrian attack, indeed, is the first notable use of chemical weapons in the last 25 years—a track record of restraint the world perhaps had come to take for granted. But we shouldn't: The example of humanity agreeing to hold back from the worst it can do is an encouraging one. It might even occasion us to wonder not so much why chemical weapons are special, but why the world has a higher tolerance for so many other means and scales of violence as "conventional"—with all the legitimacy that term implies.
Richard Price is a professor of political science at the University of British Columbia and author of the book "The Chemical Weapons Taboo."