Last week, the Wall Street Journal reported that Syria's government has been moving its stockpile of chemical weapons -- thought to be the world's largest. It is not clear whether the regime is preparing to use them or simply trying to keep them out of rebel hands, but either way the news was disturbing: The use of chemical weapons would radically escalate a conflict that has already claimed more than 10,000 lives, and the prospect of unsecured stores of nerve agent raises serious proliferation concerns. As Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, warned American lawmakers in March: "We need to be especially alert to the fate of Syria's chemical weapons. They must stay exactly where they are."
With the exception of reports that the CIA and other foreign intelligence agencies are covertly providing arms to Syrian rebels, the United States has been unwilling or unable to take military steps to stop the slaughter of protesters. That could well change in the event that Bashar al-Assad's regime deployed chemical weapons -- the pressure for international action would certainly increase dramatically -- but any air campaign, like the one that helped oust Libyan dictator Muammar al-Qaddafi last year, would have to face Syria's anti-aircraft systems, which have grown more advanced in the last five years thanks in large part to sales from Russia.
Meanwhile, Assad's assault on the rebels -- with armor, artillery, and aircraft -- continues unabated. Building on FP's earlier analysis, here is a detailed look at just how dangerous Syria's arsenal is: