One, as I've noted, ISIL is an enemy of the non-nutball resistance:
The biggest surviving rebel stronghold in northern Syria is falling under the control of al-Qaeda-linked extremists amid a surge of rebel infighting that threatens to vanquish what is left of the moderate rebellion.
The ascent of the extremists in the northwestern province of Idlib coincides with a suspension of aid to moderate rebel groups by their international allies.
Their international allies have suspended aid to compel them to unite.
So the defeat of ISIL gets rid of a potent enemy of the "moderate" rebels as much as it gets rid of an enemy of Assad. And recall that the Assad regime and its allies spend relatively little of their time fighting ISIL.
As the article notes above, the jihadis have turned on the other rebels as the moderate rebels (but not the jihadis) take part in so-called peace talks sponsored by the Russians. The jihadis have less reason to think of the moderates as co-belligerents against Assad if those rebels are willing to talk to Assad and leave the jihadis to face Assad and his Russian bombers.
Which is exactly the purpose of a Russian "ceasefire." Which I also mentioned earlier. (It makes me feel better that I just give my own opinions when I see that I basically redo a post after forgetting I wrote it.)
Two, ISIL and other jihadis are a great boost to Assad by allowing him to pretend in propaganda--both domestically and internationally--that the entire resistance is tainted by the jihadis.
Three, if the jihadis are defeated, many of the fighters who aren't really jihadis will migrate to other rebels if those rebels seem credible. One reason the jihadis gained recruits is because they are more effective.
And four, if we manage to build up a better class of rebels in the fight against ISIL, they can continue the fight--gaining fighters who defect from the jihadi groups--against Assad with fewer problems when ISIL is finally defeated.
Of course, for any of that to work we have to think of Assad as the enemy and ultimate target. Under President Obama, Assad went from foe who we might have bombed to partner in a faux chemical weapons deal to a quasi-ally opposed to ISIL in Syria.
It is tempting to just accept Assad to end the bloodshed and pretend that we have stability and quiet when in fact Assad will just be quietly crushing resistance to him.
But if Assad wins this clash, the deaths will have been for nothing. And the fight against his Alawite-led minority regime (him or his successor) will begin again in a generation perhaps.
And in the meantime, Assad will seek revenge against America and others who struck him but did not kill him.
Yes indeed, if Assad goes, there will be trouble. And if he stays it will be double.
What will Trump decide on this key question?
UPDATE: Pro-Assad forces have captured Palmyra from ISIL.
UPDATE: Hezbollah ground forces were key in the attack, it seems.
UPDATE: The Russians beg to differ, claiming their advisors, planes, and special forces were "decisive."
One thing we know for sure, the Syrian armed forces certainly weren't the key force.
And I don't buy the Russia-claimed body count for the battle of over a thousand ISIL KIA/WIA.