You aske:Next time the Chechens or other Islamofascists simply show up with gas masks. Then what do we do?
If it was anesthesia, gas masks would do.Nerve gas, however, will go thru clothing and thru skin. They would have to wear MOPP suits or something similar to protect themselves. And then, as the Russians are well aware, all you have to do is add a chemical to make the MOPP suits deteriorate quickly, so that they allow the gas to penetrate protective gear.
MOPP suits were used in the old cold war era, presumably there are new suits to protect our GI's against Sadamm's gases.
http://www.nbc-med.org/SiteContent/HomePage/WhatsNew/MedAspects/contents.html