The dangers associated with Syria’s chemical weapons (CW) are a dire example of why non-proliferation of unconventional weapons must be a top international priority. Up until a few short months ago, Syria’s chemical weapons were typically seen as for deterrence purposes only. Offensive use of the weapons was deemed suicidal and hence unlikely.

There is now a real alarm that Syria’s chemical weapons might be used, and not just in response to nuclear threats or foreign invasion. The worry, rather, is that the Assad regime might deploy the weapons against his Syrian opponents or that the weapons could be seized by radical forces aligned with al-Qaeda or other groups that might seek to use them in terrorist attacks elsewhere. Hence President Obama’s stern warning on Monday that Syria would face American military intervention in the event that chemical weapons are moved or prepared for use. An aide later clarified that Obama’s warning about "moving" the weapons meant movement that would make the arsenal more vulnerable to seizure, not movement intended to secure the arsenal.

The concerns are not fanciful. Although a Syrian Foreign Ministry spokesman last month said the weapons would never be used except in the case of external aggression, the government has repeatedly characterized the opposition forces as foreign instigated. And just as Saddam Hussein in 1987-88 infamously slaughtered Iraqi Kurds with mustard gas and nerve agents, it is conceivable that in the demonization phenomenon of a sectarian civil war, Assad loyalists might see their opponents as deserving targets of chemical attack, especially in a last-ditch defense of the regime.

The prospect of chemical weapons "falling into the wrong hands" is even more real, given the degree to which the stockpiles are dispersed and the number of fighters in Syria with shadowy links to al-Qaeda and other radical groups. Syria reportedly has some two dozen CW storage sites, some close to areas of unrest. Western intelligence agencies have a better picture of Syria’s CW following the defection of military officials involved in Syria’s program. Yet the intelligence agencies cannot be completely certain, and they are mindful of the recent Libyan experience. There, despite a relatively benign environment and cooperative attitude on the part of the Libyan government after Ghaddafi agreed in December 2003 to abandon his nuclear and chemical-weapons program, not all of the Libyan CW was fully accounted for. Additional storage sites turned up in October 2011. The likelihood that this was more a case of bureaucratic oversight than purposeful deceit does not allay concerns. Dispersing stockpiles increases the margin for error and offers more leeway for looting and insider collusion. Individual chemical weapons can be carried or carted away.