Trying to unpick who is responsible for what in this conflict is a nightmare. There are certainly more than two ‘sides’ involved, with the rebels ranging, to begin with, all the way from ‘actually not that bad’ to ‘unspeakably savage IS extremists’. Assad, with Russian backing, started out by attempting to eliminate the reasonable end of the rebel spectrum (at which he has been pretty successful). So now the going’s getting tough and foreign opposition is mounting to his increasingly brutal ‘endgame’ tactics he can ask whether the foreigners really want to replace him with the remaining rebel psychopaths. Clearly the Russians don’t want to, and I reckon that if it came to it the Americans wouldn’t either.