Thanassis Cambanis

[Orginally published at The Blog of the Century.]

Chemical weapons hold a special kind of horror. Ever since the widespread and horrifying use of chlorine and other poison gases in the trenches of the First World War, most nations have agreed not to use any of the increasingly sophisticated agents they have concocted.

It is because of this well documented taboo and the Chemical Weapons Convention that the United States government has said that it “will not tolerate” any deployment of chemical weapons in the Syrian conflict.

But beyond moral revulsion, what will it mean not to tolerate the use of chemical weapons? What if clear and convincing evidence is presented that Bashar al-Assad has used nerve gas or some other chemical weapon against his citizens? What is the White House to do differently—and why, ultimately, should this particular method of mass murder rise to a new level than the workaday means (mortar shells, bullets, rockets, bombs) employed until now to kill upwards of 70,000 people in Syria?

There’s an argument to be made that chemical weapons are potentially so lethal, and so easy to spread, that states must establish a strong deterrent to their use. But that thinking doesn’t really hold up. Iraq used chemical weapons against its own citizens in the 1980s with support from the US government, which tried to blame Iran for the battlefield use of toxins. In that case, chemical weapons were just one atrocity among many in an eight-year conflict, and the world didn’t see a spate of nerve gas attacks by stateless militants.

In Syria today, the White House must decide whether to invest more resources in the conflict. Already, the US is arming and funding the rebel factions that it finds most palatable. It has held back from doing more because of the plethora of Islamist extremists in the opposition and because of the uncertainty of what would follow in the event of a state collapse in Syria. If in fact the Syrian regime is using chemical weapons, there would be more urgency to resolving the question of whether the US should do more.

But the basic calculus won’t change.

The US wants to see a stable Syria, which is unlikely to happen any time soon, and unlikely to happen at all so long as Bashar al-Assad is in power. So far, there is no clear alternative. On one side, a bankrupt family regime; on the other, a splintered opposition with no unified leadership, no clear plan for after Assad, an Islamist flavor and a major streak of jihadi extremism.

The US and the other foreign sponsors of the opposition have funneled money and weapons to their preferred groups, hoping that incremental and indirect intervention will mould the opposition into a more coherent structure. This might or might not happen, but until a viable leadership actually controls a sizeable portion of the rebels, outside powers—including the US—are unlikely to escalate their involvement. This constraint holds whether or not the regime is using chemical weapons (and whether or not, as many allege, some factions of the opposition are also committing war crimes).

Confirmed chemical weapons use will surely create a public outcry and intensify the moral case for intervention, and the ensuing pressure will surely affect the White House calculus. But it’s unlikely on its own to make the US go to war in Syria, or propel a coalition like the one that intervened in Libya. That kind of game-changing development will require a real shift in the structure of the opposition.

Greater crimes by the regime—be it use of chemical weapons, or ever more prolific massacres—could galvanize such changes. But misbehavior or crimes committed by some rebel factions could well cancel out any momentum to get involved.

The latest evidence is worrisome indeed. But it doesn’t yet open the way for an international intervention.