An air campaign alone would be unlikely to solve the challenge. While the U.S. can destroy deeply buried targets, Charles Blair--senior fellow for state and non-state threats at Federation of American Scientists--said that "no country has the burrowing capability, even with nuclear weapons, to destroy very deep targets without creating an enormous radioactive fallout cloud." Even strikes on targets above ground would risk spreading the agent. These strikes, Blair said, would cause an "unacceptably high number of agents still in existence and still available."
Leonard Spector, deputy director of the Monterey Institute of International Studies' James Martin Center for Nonproliferation Studies, outlined a smaller-scale military option. Surveillance assets might observe an empty truck convoy approaching one of the chemical sites, Spector said. A targeted operation with drone strikes or even special-forces troops could disrupt this activity.
The U.S. could also train its Arab League partners to secure the sites if more widespread devolution occurs. Spector said that June's Eager Lion 12 exercise in Jordan brought together 19 nations to work on various contingencies, including the possibility that chemical weapons could be taken across Syria's borders.
However, if agents are already walking away, it's too late for the best possible outcome, Blair said. As rebels (or terrorists) try to figure out how to use or even transport the different agents, there could be potentially significant casualties, Blair said. Fear alone of loose chemical weapons could spark widespread panic and devastate the global economy.
In the meantime, Spector argues the U.S. should encourage the sites' trained custodians--who may be contemplating defection--to remain in place. "You want to advise them that if they stick to their mission of protecting these sites ... that they will be treated in a special category that will get some protection," Spector said, calling on Washington to advise the Syrian opposition to get this message out. However, Syria's opposition is still disorganized, and the West retains a lingering distrust of opposition groups with possible extremist ties.
The recent past offers some tough lessons. Libya's arsenal pales in comparison to Syria's sophisticated conventional weapons systems, but the U.S. allocated some $40 million for American and European specialists to clear the roughly 20,000 surface-to-air missiles and other weapons believed to be within that country. But the Libya mission launched after the violence and NATO bombing campaign left sites open to looting. The U.S. still cannot account for all the weapons thought to be missing. Loose weapons from Libya are believed to be partly responsible for rising violence in nearby Mali, where the democratically elected president was overthrown in a March coup.
Best-case scenarios for Syria's chemical weapons appear to be pipe dreams: Assad is highly unlikely to willingly leave power willingly and allow a negotiated transition; and his downfall isn't likely to come from a clean overthrow by the rebels, either. Assad's hold on power inadvertently prevents the need for a rapid response to contain the massive stockpile chemical weapons--but Washington must develop a long-term plan if its policy is truly for the strongman to leave power.
There is one outcome that could demand international action before that day comes: if Assad deploys chemical weapons against his own people. "The humanitarian consequences would be so grave, and the international outrage so severe, that could lead to a much more substantial intervention," Spector said. Even Assad's strongest ally, Russia, would be hard-pressed to argue against it. "That is an unspoken red line."