Worrying about post-Assad Syria may be moot. We seem to be at post-Syria Assad after the effective collapse of the Syrian army.
I read a couple articles that filled in some gaps in my understanding of the Syrian battlefield. It was a while ago but I didn't get around to finishing this for a while.
This is the state of the fight from high altitude (map from this article):
Note that the very light blue areas basically represent uninhabited spaces where control colors are pointless at this stage.
Let me start with a summary of what I think the situation is apart from seeing the noted articles.
The Syrian army has largely lost its infantry, becoming a backbone of logistics, armor, and artillery.
The infantry has been replaced with militias that are largely immobile and tied to their local areas.
Indeed, the casualties have been so high for Assad's force that I wondered how much more his army could endure before breaking.
Assad relied on firepower (air and artillery) plus a core of mobile Syrian forces, plus a Iran-backed Shia foreign legion and Hezbollah as the shock troops to generate offensive power.
Russia and Hezbollah have added in special forces to Assad's assets.
Russia has, since September 2015, also added air power and logistics support.
Small numbers of Russian mercenaries are available to bolster Assad's forces.
Hezbollah has recoiled from the shock troop role because of heavy casualties (over a thousand dead, if memory serves) and is now more interested in protecting the Syria-Lebanon border.
Assad lacks the population base to really expand his military to fight for all of Syria.
Early in the civil war I believed Assad should actually contract his realm more than he has to allow the troops he has to control the territory and people. Looking at the map you can see that Assad has mostly done that. But he has lost a lot of men being forced back to that realm rather than contracting to it early on to conserve his army.
When I argued this in January 2012, I thought an arc from the Turkish border to the Israeli border should be done for various strategic reasons.
Later I counted troops and thought that Aleppo was too far north and the Israeli/Jordan border areas were too far south to hold. Indeed, I doubted Assad could really afford to defend Damascus, believing that he should contract to a rump Syria based on the coast with an inland buffer out to the main north-south highway through Hama and Homs.
Yet I did admit that an attempt to retreat from the outlying areas risked a collapse of Assad's army just as South Vietnam's army collapsed in 1975 when they attempted a strategic withdrawal in the face of North Vietnam's massive invasion.
America's policy is that the defeat of Assad could lead to post-Assad chaos, so we attempt to "pressure" Assad into leaving the front office without trying to get rid of the Assad regime infrastructure, hoping to get a kinder and gentler Baath Party moderated by opposition participation.
Now we have this article and also this one linked in that article about the state of the Syrian army that indicates we may already be in a post-Syria Assad where the so-called stability of the existing regime has already been bypassed with a largely decentralized structure in the west that would survive the defeat of the Assad regime.
Let me summarize what the articles (here and here) add to my understanding.
Basically, the Syrian army's army divisions had--prior to the war--evolved into virtual feudal realms that exercised political and economic power in regions they were responsible for. As the infantry died in the civil war and was replaced by militias as the infantry component, the divisions became the technical backbone (firepower, armor, combat support, and air power) of military efforts that suffered fewer casualties. The lines of economic, military, and social power that extended throughout the region that existed parallel to the chain of command up to Damascus allowed the Assad regime to essentially subcontract control to regional power centers that are more allied to Assad than they are subordinate to Assad.
Interestingly, Russia provides support through the formal military channels while the Iranians directly support the militias.
As virtual fiefdoms, these regionally based sub-state powers rely on
local resources extracted from the population that lives there rather than relying on Damascus for support. Assad is transitioning from an autocrat who rules to a figurehead who reigns over the locals he cannot control with the relative power.
Remember, an army is a combined arms force of infantry, artillery, armor, and other supporting combat support and combat service support units designed to fight as a whole with the support of air force or army aviation assets.
Syria's infantry seems to be largely gone. So Syria does not have an army.
And the Syrian government seems to have largely lost control of the regions where the army divisions are more like regional governments that rely on militias (where Iran has a lot of influence) for their line troops and rely on the regime (and Russia) for support for heavy weapons and air power support.
The result is that the defeat of the Assad regime would not mean the takeover of Syria by ISIL that fills the vacuum left by his defeat. ISIL could not do that because there is no vacuum. Local power sources allied to Assad already control much of what we call Assad's rump Syrian territory.
So what does this mean? The Syrian army has collapsed. In a way it is like an advise and support force of firepower, armor, and logistics backed by air power sent in to help poorly trained local forces fight their war. And without local forces--whether Syrian or imported militias--the Syrian army would be unable to fight the war.
Without an army as we understand it, Assad does not truly control Syria. Regional entities based on the army divisions run their areas as sub-state sovereigns.
But neither is Assad capable of losing Syria. He has already lost it. If he goes down, the regional entities would live on. They would require alternate support that they received through Assad, but they'd still have Iranian support. Would Russia really just pull out of Syria or would they then make direct deals with army division-based regional feudal realms to support them?
And interestingly enough, Assad's strategy of bombing enemy civilians to drive them from Syria not only works to hurt the rebels but works to hurt the feudal realms under him by depriving them of the people that provide the local resources that the division-based feudal realms rely on to sustain these entities.
Even as Assad victory over the rebels would not end the war. While local feudal entities might voluntarily submit to Assad's formal authority again, they might resist and compel Assad to gather allies to compel these entities to bend the knee to the central government again.
And it means that focusing on the defeat of Assad first would not empower ISIL to control Syria.
And even defeating ISIL does not necessarily help Assad as much as it helps the regional feudal "lords" to gain territory and resources, which strengthens them relative to Assad.
Which means that we have post-ISIL options to oppose Assad by reaching out to these feudal "lords" and offering support against both Iranian influence through the militias and renewed Assad control.
I've long held that we can't count on Syria's Kurds to be much help outside of their home regions, making the Kurds less than helpful in a post-ISIL fight. But we might have options to cut deals with the feudal lords who may prefer to be a big fish in a small pond rather than let Assad resume business as usual.
So perhaps I have been wrong to have wanted to defeat Assad first and then focus on ISI, rallying Syrians to fight for a post-Assad Syria free of jihadis. The defeat of ISIL does not automatically help Assad as much as I thought before I read those two articles.
Syria as a political entity is already gone, it seems, with the UN seat just a legal fiction. The question may be how many deaths are worth it to knit it back together and will Syrians be willing to fight for a unitary Syria again after ISIL is defeated in the east by the American-formed coalition.