If, as the letter from the White House claims, evidence of small scale sarin nerve has attacks have been found in physiological samples, there are a multitude of explanations as to why they exist. The letter itself notes that officials are as of yet still unsure of the chain of evidence behind the physiological evidence. The United States has pledged time and again that the use of chemical weapons draws a sharp line. If actors in the region could prove that chemical weapons were used, they could theoretically bring the US in on their side. But assuming that the samples did contain actual evidence of a chemical attack, does this automatically cross the line the US set.

(I will preface this with two caveats: first, this is a theoretical exercise. Second, the idea that chemical weapon use constitutes a red line is something of an absurdity with regards to Syria. When thousands have been killed through more conventional means, either bombs, bullets, or bludgeoning, singling out a single weapons system, even one as heinous as chemical weapons, seems trite. This is a conflict where SCUDs have reportedly been used against population centers. Third, I understand that it’s unlikely chemical weapons could be used as I describe below. It’s more likely that the regime sanctioned the use of weapons. This is theoretical.)

The belief here is that, if chemical weapons, specifically Sarin, have been used, they were used at the behest of the regime. The first assumption inherent to this idea is the uniformity of the Assad regime, or at least the uniformity of its communications structure. The regime does not function as a hive mind, rather, like most governments, it is composed of multiple entities, each with their own interest. These entities run the gamut from Assad himself to, say, a colonel in charge of a military post, far from Damascus, in danger of being overrun.

From these two examples within the “regime,” it is fair to acknowledge that it is made of a relatively disparate group of actors, each with their own set of interests. Much ink has been spilled to this effect, but Bashar himself is unlikely to condone a nation-wide policy of chemical weapons attacks. He knows this could potentially bring the US (and the world) down on his head. The hypothetical colonel in the field may feel differently.

Say his life is in danger. His post is being assaulted, and the conventional arms he and his men have at their disposal aren’t enough to break the siege. He has access to chemical weapons, and knows that the fear that three unconventional arms create is almost as useful as the effectiveness of the arms themselves. He makes the conscious decision to use chemical weapons against those besieging his position. In his haste to use them, the blowback of the weapons leads to civilian deaths from the population center nearby. Word, and evidence, of the attacks gets out to the wider world. Do the actions of this minor actor within the regime equate to the actions of the regime as a whole?

This sequence of events actually parallels an event from the history of North America. In 1763, during Pontiac’s Rebellion, Fort Pitt fell under siege. The fort, which was built and occupied on the site of an earlier French fort, remained under siege for over a month. Jeffery Amherst, the British general responsible for the fort, sent troops to reinforce the garrison there. The troops, under Colonel Bouquet, broke the siege in August, nearly two months after it had begun.

While preparing to lead the march to Fort Pitt, Amherst sent Bouquet a letter inquiring as to the possibility of spreading smallpox amongst the Indians, intentionally, as a means to “reduce them.” Bouquet agreed with the idea, and suggested using blankets. The idea was discussed over the course of three letters between the two. Unbeknownst to both of them, the garrison at Fort Pitt had already acted without knowing of their plan, providing the representatives of the Delaware tribes with blankets from the smallpox ward.

The question historians have been asking since is thus: do the actions of those at Fort Pitt, including the correspondence of Amherst and Bouquet, constitute a policy of genocide by biological warfare, or do they reflect the despicable actions of the men fighting to quash the rebellion? Most historians trend towards the latter, that it does not reflect a policy of genocide, but rather one more attempt to break a siege. That distinction of policy versus single action by a single actor is huge. Claiming that Amherst’s writings constitute a policy of genocide is much more terrifying than saying they are the war-weary writings of a bigot and a xenophobe. Later American actions with regards to Native Americans aside, that claim would be a black mark on the history of the human race, to say nothing of the development of the United States.

This brings us back to the Syrian colonel and the red line on chemical weapons use. If the colonel’s actions were not the result of a policy of chemical weapons use (as in, he was told by his commander, who was told by his commander, and so on and so forth, reflecting a policy endorsed by the leaders of the Assad regime), his actions would seem to mirror those of the captain in charge of Fort Pitt, desperately looking for any way out of a deadly situation. Because his actions do not reflect a policy of chemical weapons use, what would US intervention accomplish? Aside from jailing and trying the colonel himself for the crime, not a lot. The weapons themselves have been common knowledge for a while. The war has been going on for over two years now. If the US intended to intervene in order to secure the weapons, they have had plenty of opportunities. If they intended to intervene in order to protect civilians; well, it’s a little late for that, too.

Therefore, it would seem that it is not enough to have evidence of the use of chemical weapons to justify intervention. That evidence could point to any number of scenarios. Cynically but realistically, nothing has changed. The regime is still killing its people, and the country is still in the throes of a brutal civil war. What would theoretically constitute enough evidence to justify intervention would be evidence, either physical documentation or human corroboration, that a chemical weapon attack is part of a coordinated policy directed from the upper echelons of the regime.

Chemical weapons exist in Syria; it is not unreasonable to assume they will be used in an active war-zone. If their active and persistent presence, coupled with the human rights atrocities, violence, and slaughter of civilians, was not enough to justify intervention in the beginning, their sporadic use does not seem to be enough now.