The Iranians or Russians are behind the change in tactics, I'd say. The jihadists are not smart enough to figure this out for themselves.
I'd say it's the Iranians. They were as guilty as Saddam at using chemical weapons.
I'm glad you're not in charge of US policy. Underestimating an enemy is a great way to lose a war.
The jihadists were smart enough to find the gaps in our pre-9/11 airline security, and exploit them masterfully to murder 3000 Americans. Credit where credit is due: 9/11 was murderous, evil, a crime against the laws of war, cowardly as an attack on defenseless civilians, but it was also brilliant in its tactical conception and execution.
And it doesn't take a genius, or a state secruity apparatus to figure out how to make chlorine gas and bottle it. Anyone with access to a compressor of the sort used to make pressurized gas cylinders and household chemicals can do it.
All the other FReepers who made chlorine gas using household chemicals when they were kids chime in now.