Rebel held Aleppo is currently entirely surrounded, and is about fourteen kilometers by four kilometers, meaning every inch of it is within mortar range of Assad’s troops. It will fall shortly unless there is a rescue mission from outside to relieve the siege. There have been rescue missions before, each of which ever more blatantly involves some new foreign power directly intervening in Syria ever more directly against the legitimate Syrian government. There may well be rescue missions again, but right now Aleppo is falling.
There is nothing wrong with Assad by middle eastern standards. In Assad controlled regions people of all religions and ethnicities are free to go about their business, whereas all the rebels except the Kurds want to kill or exile every religion and every ethnicity different from their own. (The Kurds just want to partition the Kurdish regions off into Kurdistan)
The problem with Assad is that during Arab Spring, the US, aka “the international community” capriciously and whimsically decided he should fall, and he did not fall, which is a slap in the face to “the international community”.
If regimes deemed problematic by “the international community” always fall, then it is a self fulfilling prophecy. If people believe a regime will fall, it will fall. So if Assad does not fall, then other regimes could potentially get away with being deemed problematic by “the international community”. This is Russia’s objective – to deny “the international community” the power and authority to overthrow any regime that displeases it. Russia does not really give a damn about Syria in particular. While “the international community” weeps sad salty tears telling us what a horrid person Assad is for fighting back against people who want to kill him, kill every member of his family, and kill every member of his race and religion, and tells us that because of this horrid crime, it is utterly unacceptable that Assad continues to rule, Russia tells us they want to set a precedent, and Syria just happens to be the place to set it. The precedent that Russia wants to set is that legitimate regimes should not be overthrown by external forces.
And in fact, since Syria became a problem, the “international community” has quietly stopped deeming regimes problematic. Which is likely to lead to more and more regimes becoming problematic. That Assad remains has already led to a domino effect, and should Aleppo fall and “international community” give up, there will be a lot bigger domino effect.
If Aleppo falls, then Assad controls all the significant urban areas of Syria, in which case it is kind of obvious that “the international community” has been defeated and should just give up. It could escalate the war by putting US soldiers on the ground, but this would undermine the pretense that the “the international community” is just the spontaneous outrage of all right thinking people, and make it look too much like the US empire. Also putting US soldiers on the ground would be war with Russia.
Of course everyone except “the international community” knows that “the international community” is just the US empire, but the US empire does not want to know it.
Whereas Islam can coexist with Christianity by making Christians second class citizens, Liberalism cannot coexist with Christianity. Christians must cheer at gay weddings, demonize fathers, and enthusiastically celebrate single mums. The existence of Christianity anywhere in the world is an intolerable threat and insult to liberalism. In Russia, the Russian orthodox are allowed to be Russian orthodox, which generates ever increasing outrage and aggressive war talk among liberals. We are moving towards internal civil war, or external nuclear war, and it is hard to say which will come first, though I expect civil war.