American interests in Syria are clear: preventing terrorists from acquiring chemical weapons; depriving Iran of its most important ally and staging-base in the Middle East; and preventing al Qaeda from establishing an uncontested safe haven in the Levant. Reasonable people can disagree about the extent to which President Obama’s proposed “limited strike” will secure these interests, but not about whether the interests are real or vital. Bashar al-Assad has one of the largest chemical weapons arsenals in the world. Al Qaeda franchises control territory in Syria and have some of the most effective fighting forces on the ground. Iran’s own military and security forces are active in Syria in defense of the Assad regime. The threat to Americans is very real.
Assad’s expanding use of chemical weapons against his own people is more than an atrocity and an egregious violation of international law and norms. It also materially increases the risk that terrorists, whether al Qaeda or Hezbollah, will get hold of some warheads. When not in use, weapons of mass destruction are generally kept in heavily guarded and secured bunkers—regimes that possess them fear both that they might be stolen or smuggled away and that the enemy against whom the weapons are aimed might destroy them preemptively. Terrorists seeking to lay hands on the weapons, generally, would either have to penetrate those defenses (usually a task beyond their means), infiltrate the guarding force (not a very plausible option for al Qaeda facing an Alawite defense force loyal to Assad), or hope that the defense collapses, leaving the position open to plunder. Even in that last case, the United States or other concerned powers, seeing the departure of the guard force, could use bombs to prevent the terrorists from getting into the facility or removing materials from it or, in the worst case, insert troops into the facilities that were compromised, whose positions are presumably well known to us.
In order to use the weapons, however, Assad’s forces must remove them from any such protective facilities, load them onto vehicles, drive them through the war-torn streets of a conflict zone, set them up, and fire them. Those activities make the weapons themselves considerably more vulnerable to terrorist seizure, especially as they are being transported. The terrorists’ problem then shifts from one of breaching a heavily secured bunker to one of raiding a convoy—a tactic that insurgents in Syria and around the world perfected long ago. Manhandling the warheads and smuggling them out of the area or the country would present challenges to the terrorists depending on the size and characteristics of the weapons—but those challenges are by no means insurmountable.
Facing such a situation, the United States would find its own responses much more complex. To begin with, would it even be known that something was awry until after the fact? Recent media reporting suggests that the intelligence community was not tracking preparations for Assad’s most recent use of chemical weapons in real time. Simply bombing the terrorists wrestling with the weapons risks setting off the weapons in a populated area. Inserting a small strike force into such an area (rather than onto a military facility separated by design from the population) would be much more dangerous and also significantly increase the risk of both American and civilian casualties. And there is the risk that the reaction wouldn’t be fast enough in any case, potentially allowing terrorists to move the weapons away from the site of the attack and forcing the United States to start an aerial hunt for them.
In short, Syria’s use of chemical weapons by itself dramatically increases the risk of those weapons falling into al Qaeda’s hands. Any action the United States and its allies could take to dissuade Assad from continuing that use—thereby persuading him to keep the weapons locked up as securely as he can—is a step toward reducing that risk.
The best solution, of course, would be to destroy the weapons or remove them from Syria. Simply bombing them from the air poses unacceptable risks, unless they are about to be seized by terrorists. There is a risk of releasing clouds of toxic gas that could kill scores or hundreds of innocent civilians, even when using advanced bombs designed to incinerate chemical weapons. Using such advanced munitions, moreover, would require putting manned aircraft over Syrian airspace, which in turn means attacking the Syrian air defense system in advance. Bombing secured bunkers also makes it impossible to determine with certainty whether all of the weapons were destroyed, while simultaneously exposing the storage facility to plunder by scattering (at the very least) its guard force. One might advocate such action, again, as a last resort, but not as a first military option.