A few thoughts on where we are with the allegations of chemical weapons use in Syria.

The stakes. Let’s keep in mind why we are arguing about this.  The President has said that chemical weapons use would be a “game-changer” (oh, how I hate that…phrase) in Syria. Why do we care if Assad gasses his people, when we’re perfectly willing to let him shell them with normal artillery? Our reluctance, I suspect, arises from the fact that our distaste for Assad is not the same thing as enthusiasm for who replaces him.

Chemical-weapons use invokes an interest that has nothing to do with the future of Syria. We have a stake in strengthening the norm against chemical-weapons use.  If Assad is using chemical weapons to hold on to power, we have an interest in ensuring that his government falls and that the responsible regime figures take their turn at the Hague.

Now, the caution: Once we go in, the gloves are off.  The Assad regime may very well try replicate Saddam’s massacre at Halabja. That was a mass murder of the most appalling scale where you aren’t really sitting around asking, “Did they use nerve agents or not?” So let’s not be hasty. Deterring large-scale chemical-weapons attacks on the civilian population is of continuing value.

The standard of evidence. Now, I happen to think the standard for involving ourselves in this mess ought to be pretty high, particularly since once the gloves are off, Assad might start gassing cities. In for a penny, in for a pound. Let me propose a standard of evidence, then we can see where we are.

First, the allegation of chemical weapons use needs to be specific to a time and place. We need a date, time, location, and (ideally) the identity of the Syrian unit in question. What we want to be sure of is that an actual military attack occurred that resulted in victims.

Second, once we have an attack, we need victims of that attack. These victims, who can credibly be placed on the receiving end of the attack, will provide blood or urine samples that show sarin use.  There is a lot of public research, thanks to the Tokyo subway attack, on how to determine if someone has been exposed to sarin if you are interested. CDC and OPCW also have nice little primers.

We have to be certain that any sarin exposure resulted from an attack. Having set a red line for U.S. involvement to deter Assad, we’ve also created an incentive for certain groups to tell stories that might result in more U.S. assistance. As I’ve noted before, these groups don’t appear particularly scrupulous when it comes to the truth. So I’d be very, very careful about leaping to conclusions.

The evidence itself.  There are two useful sources describing the evidence.  First, the Obama Administration sent Congress a letter that lays out the details. Second, Geoff Dyer and James Blitz have some excellent reporting in the Financial Times that helps explain the letter. Hagel has now also released a statement, but it doesn’t add much.

Here are the two key sentences from the letter:

This assessment is based in part on physiological samples…. [However,] the chain of custody is not clear, so we cannot confirm how the exposure occurred  and under what conditions.

In other words, we have samples showing someone was exposed, but we can’t prove when, where, or how.

Dyer and Blitz add some very important details from “a senior western diplomat.” The physiological samples are two samples taken from different victims at separate locations and on separate dates. The U.S. analyzed one sample (possibly at Edgewood), and the UK Defence Science Technology Laboratory at Porton Down analyzed the other.

One can immediately see the problem: The samples show sarin exposure, but they are not linked to specific, credible events.

Emphasizing the chain of custody. Suddenly the constant references to the “small scale” use becomes more clear — we don’t have multiple victims in a single use, as might be expected if the Syrians gassed a military unit or a local community.  At most, we have two events in which only one person was exposed.

For all we know, these two poor souls stumbled into sarin canisters while ransacking a liberated Syrian military sites. I don’t say that to be callous, but rather because strange things happen on the battlefield. Remember, in 1991, U.S. troops detonated a pit of munitions at Khamisiyah in Iraq only to discover that the munitions contained sarin. The image atop the post is one of a series showing U.S. forces detonating the munitions at Khamisiyah, exposing thousands of U.S. service personnel to low levels of sarin. This was the worst such event, but not the only potential exposure of U.S. forces in 1991 to nerve agents.

There are many ways that Free Syrian Army fighters might find themselves exposed to sarin.  I still think caution is important.