[CurlyDave]

...Assad just lost 20% of his Air Force. He can’t sustain another loss like that.

There are plenty more airplanes in Russia. Depending on how Putin wants to play it, he can sustain losses like that for a long, long time.

[Helicondelta]

Both Assad and the Russians are broke. If they had an unlimited budget they would have slaughtered all the rebels by now. The main reason for them using chemical weapons is probably the low cost.