Al nusra is al queda, usually an Isis ally.
They're not sure yet what it was. Some reports say chlorine.
It's not far fetched to believe that isis/al queda gassed civilians for propaganda purposes.
Why is gas worse that bombing, shooting, beheading, crucifying, burning people alive?
Is it worth going to war with Russia and Iran over?
1) Captured weapons. ISIS has reportedly captured chemical weapons too. The problem is the timing: It’s pretty unlikely a rebel group could launch a chemical attack to coincide with the air attack. Not impossible, but, unlikely.
2) Old info. Al Nusra is pretty much splitsville with ISIS (for some time now.)
3) Did you read the info. on Sarin?
Many people killed outside. Hard to do with small chlorine attack. Plus tissue samples, symptoms, etc. Sarin antidote helped (would not help chlorine gas victims.) Unless there is massive faking going on, at this point, probably 99% certainty it’s Sarin.
4) I have no illusions about what Al Nusra might do for propaganda purposes, but, in this case it’s the details of how they’d pull it off that make it look unlikely that they are the culprits. At a minimum, they’d have had to be tipped off about the airstrike, well in advance. ISIS probably has more capability, but was not in that town.
5) That’s a LONGGGG discussion. Basically, civilized (more or less) nations have agreed use of chemical weapons is a form of terrorism. Ditto for burning people alive in cages, hacking their heads off, etc. Uniformed soldiers shooting or bombing each other, not so much. It’s all where you draw the line. Some would consider it unacceptable if I shoot an intruder coming at me with a knife. Luckily, my gov’t does not, at least not yet.
6) Russia appears to have pretty much stood to the side, in return for us giving them “fair warning” and going to considerable effort not to harm their personnel. Plus, I suspect they have other reasons to let Assad get his knuckles rapped. (That’s another long discussion!)
Now, if Iran wants to get into it, that’s fine by me. It’s going to happen sooner or later, unless there is a big change in their gov’t. Better now, than when they have nukes.