By Andrew J. Tabler, Washington Institute–

A conversation on how Assad and Russia have achieved a major victory in a strategically crucial city, and at what cost.

The following Q&A with Washington Institute fellow Andrew Tabler was originally published as part of an Atlantic article by Kathy Gilsinan.

Kathy Gilsinan: The

[eastern parts of the] city had been held by rebels for four years. How did it fall so fast?

Andrew Tabler: This has been going on for a long time, this operation. Aleppo was surrounded in the summer, earlier this year. There were attempts to break through that siege but they were not sustainable. The way the regime has carried out these siege-and-starve operations — which they call ceasefires — is you surround an area and you squeeze it. In squeezing it, you weaken the population there — there haven’t been humanitarian deliveries of any really sizable amount into East Aleppo. You also weaken the military groups in that area, because they cannot be resupplied; also the crisis led to some infighting among different opposition groups, which didn’t help. So all of those things led to a situation where, with more support from Russia and from Iranian-backed forces, [regime forces] were able to squeeze the pocket substantially and now we’re in the situation we’re in today.

Gilsinan: So what’s happened quickly is just the physical regaining of territory?

Tabler: Right. When you set up a siege — and the regime has done this — you determine the rules, and the siege around Aleppo has been quite harsh. So, in doing that, you put tremendous pressure on and you create tremendous fissure between the fighters and the local civilians, who justifiably would like some relief and were being denied proper nutrients, sustenance, and so on. In a way, this is breaking into the news now but it’s been going on for much of this year. There have been attempts to try and deal with it from [the U.S.] side, but they have come to nothing.

Gilsinan: I see a lot of reporting about the United States turning a “blind eye” to this. But [Secretary of State John] Kerry has been working really hard to try and get a ceasefire. Why do you think that hasn’t happened?

Tabler: The U.S. hasn’t turned a blind eye to what’s going on in Aleppo, but it’s the means they were willing to use to achieve their objectives. They’ve tried to get a ceasefire, they’ve tried to make humanitarian deliveries, they tried to get into an agreement with the Russians in the summer to target terrorists, as long as the Aleppo siege was broken and humanitarian deliveries were available. That agreement was stillborn after the U.S. accidentally hit regime soldiers out in Deir Ezzor, and a still-unknown, but widely suspected [to be] Russian, aircraft bombed the UN convoy. That blew up the agreement on the launch pad.

It’s not true that the U.S. hasn’t focused on this. But the only way to keep that siege from happening would have been to escalate militarily, and that’s what President Obama didn’t do, either directly, through direct intervention, [or] also indirectly, through the provision of weapons [to the rebels]. And most interestingly, they were unwilling to carry out airdrops into East Aleppo. So in that sense, the U.S. fell well short of achieving their objectives, and it’s another devastating loss for U.S. Syria policy. What else can you say?

Gilsinan: Where do the civilians go? Where do the rebels go? I’m seeing reports of sort of mass executions. But they can’t kill them all, can they?

Tabler: No, I mean, I don’t think that they will. There will be mass executions. There’s going to be an incredibly brutal roundup, which is going on at the moment. Some of the civilians have left the corridors on the “green buses,” what they call them, these Chinese buses. Some fighters have evacuated to Idlib [the rebel-controlled province to the southwest of Aleppo].

I think the objective will be to get fighters and civilians out into Idlib. And once they’re out in Idlib, then I think that, and many people think, will be the next area, will be teed up for bombardment by either the Assad regime, or the Russians, or both. But I think there will be a lot of way stations in between.

Notice that the regime’s manpower shortages are so severe that I don’t think they’re going to immediately launch into a campaign to retake the rest of the country. I think they’re going to go into negotiations, albeit on Assad’s terms. You notice that as the regime is squeezing Aleppo, it lost control of large parts of Palmyra [the historic city it seized from ISIS earlier this year]. And that wasn’t a coincidence. This is where the Russians have a lot of leverage; if they don’t support the Assad regime and their Iranian-backed allies, their ability to retake territories is very limited. That could help spur talks. The question is to what end? And it’s certainly not with Assad leaving power. Instead it’s something else.

The regime only has about 20,000 to 25,000 deployable manpower that can go outside of frontline areas, retake and hold territory. It’s very limited. NATO estimates are at 20,000; Russia estimates are at 25,000. Let’s say it’s even double that, 40,000 soldiers. Is that enough to retake [the] two-thirds of Syrian territory that’s outside of the government’s control, anytime soon? It’s just not. And that’s the reason why the fall of Aleppo is a devastating loss for the opposition, and it wins Assad an important battle, but I don’t think it wins him a war. I still think this is going to go on; Syria’s going to be a divided country, and President Trump is going to have to deal with that divided country if he really wants to make the situation any better and, most importantly, deal with the migrant and the terrorist threats that are coming out of Syria.

Gilsinan: How can anybody help the civilians?

Tabler: It’s very difficult at this point to do anything to help the civilians. Other than to get more aid into Idlib, where they’re being evacuated to. Diplomatic pressure by the Russians could get the regime to pull back or be more lenient in terms of their treatment of civilians. It’s very hard for anyone to get the regime to do that. It’s not like shame is really going to work on any of the parties here.

Gilsinan: So what do Russia and the Iranians do next in Syria?

Tabler: The big question. Are they on the Assad page, or not, going forward? The regime’s limited manpower means the path to an Assad victory necessitates the import of more and more Iranian-backed Shia militias. Will Russia go along with that? Or will they get Assad to the negotiating table? My conversations with Russians indicate they do not want to put more ground forces into Syria. They are also aware that Shiite militias are not a long-term answer. Could we see a split between Iran and Russia in Syria? In the short term, I doubt it. But in order for Russia to leave the Syria conflict, it needs a politically stable end state. Russia needs President Assad to enter into serious political talks with the opposition to reunite Syria. Problem is, President Assad has been adamant he’s not interested in that. An early challenge of the Trump administration will be how to wheel and deal to split Russia and Iran apart in Syria.

Gilsinan: Anything else you wanted to add?

Tabler: I think it’s important to note that President-elect Trump in his selection of Rex Tillerson [for secretary of state], that indicates to me that he is going to try and see where there are cooperation possibilities with the Russians. And this might be an opportune time to check the status of that effort. You’ll probably see them try and resurrect the joint implementation group agreement [that fell apart this summer] in the short term, in terms of the targeting of terrorists. The real U.S. policy question will be: Does President-elect Trump stop the Title 50 covert program to support the rebels? You’ll notice, in his interview with The New York Times, he went off the record when he was speaking about the issue. So that is interesting because that would mean that it would deny the rebels TOW anti-tank missiles, which would [make it] hard to combat Syrian armor.

But would it end the war? Probably not, because most of the weapons that go in there are not supplied by the U.S. [The program] is designed in the name of overthrowing President Assad and pressuring him. And that’s all it’s been doing — pressuring him. Obviously, President Obama is not trying to overthrow President Assad — he never tried, he was never serious about it. What it really does is get us a lot of good intel and leverage over different opposition groups, which are not jihadist in nature, or Salafist, and that’s important if you’re trying to really combat terrorism. If you cut that program, you’re going to lose a lot of good intel and I’m not sure militarily that’s something we really want to do. It’s going to be an early dilemma for President-elect Trump.