Judging by his old "red line" on Syria, the one that was convenient until it wasn't, President Obama's "calculus" with respect to the humanitarian calamity in Syria has changed multiple times already. In August he said this: “A red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized.” Then his Defense Secretary Leon Panetta admitted at a Pentagon press conference in September that the United States had lost track of some Syria’s chemical weapons. Now NBC News and Wired magazine have reported that U.S. officials believe that the precursors for sarin gas have been combined and loaded into aerial bombs (albeit not yet onto aircraft), where they await Bashar al-Assad’s personal order for deployment. Panetta, who I hope has found the chemical weapons he misplaced last fall, now claims: “I think there is no question that we remain very concerned, very concerned that as the opposition advances—in particular on Damascus—that the regime might very well consider the use of chemical weapons. The intelligence that we have raises serious concerns that this is being considered.” Now's a good time to survey the devastation Assad can yet unleash upon a ruined country, and what the West plans to do about it if he does.