As fighters from the Islamic State of Iraq and Syria (ISIS) prepared to march towards Baghdad on Friday, the often fragmented forces of Syria’s opposition were forming a coalition to ward off the group’s anticipated expansion into the east.*
“Opposition forces are mobilizing in response to ISIS gains,” says Steven Heydemann, vice president of Applied Research on Conflict at the United States Institute of Peace in Washington. “We have seen interesting alignments between Jabhat al-Nusra, the Islamic Front and Kurdish armed units. That’s a set of actors we would normally expect to be in conflict with one another, and now they are joining forces to move against ISIS, especially around the border.”
The anti-ISIS coalition that could emerge could also involve tribes in the east, some of which have close ties to Saudi Arabia.
“If they were to join in this broader coalition against ISIS, [this could be] a coalition that would contain ISIS,” says Heydemann.
A rebel coalition isn’t the only factor that could slow the group’s push into Deir Ezzor. As it expands its Iraq offensive, a march on Baghdad will take priority, potentially forcing a diversion of manpower from Syria. An estimated 7,000 to 9,000 ISIS members are currently fighting in the two countries.
“This has drawn a lot of their fighters away from Syria towards Iraq,” says Omar Lamrani, a military analyst at Stratfor who studies the Syrian regime. “It’s a finite number. If the Iraqi government stages a counteroffensive, they will likely keep bringing in reinforcements from Syria. At this point, ISIS considers its Iraqi gains more important than what it has in Syria. It will maintain the bridge between the two countries, it will prioritize Iraq to the detriment of its operation in Syria.”
Analysts do say the spoils from this week’s Mosul surge will boost the confidence of ISIS fighers in Syria as they move east, aiming to take over a broader swath of the country. They say the group is eyeing terrain from its stronghold in Raqqa to Kurdish-controlled Hassakeh, then on to the northern provinces of Idlib and Aleppo.
Whatever the short-term results of the battle, any long-term gains “will really depend on what the international and Iraqi reaction to this is,” says Chris Phillips, lecturer at the University of London and the former Syria analyst for the Economist Intelligence Unit.
“If it’s heavy, with a military response that tries to crush ISIS and nip them in the bud, this week could end up being positive for ISIS’s Syrian rivals. But if we see a cautious approach that allows them to consolidate their gains, it will be negative for opposition forces,” says Philips.
By his assessment, Western powers would do well to launch an strong-armed response.
“The international actors on Syria are united over the ISIS crisis. They’re all scared of ISIS. So you’d hope this would lead to a realization that they have a common interest and that they should start forming a group with an aim of trying to end the chaos.”
Adds Lamrani: “If this promotes a major assault by the Iraqi military or the U.S. by airstrikes, it could severely damage ISIS both in Iraq and Syria. It might also encourage Western actors to send more weapons and support to non-ISIS fighters in Syria. I suspect there’ll be calls now to arm moderate groups against ISIS, which won’t work because what is needed against a group like ISIS is the power of the state. You’re never going to be able to provide [tanks and other large] weaponry to the moderate rebels in Syria.”
Syria’s rebels, especially those aligned with the West, have had to cope with major capacity constraints, struggling to maintain a cohesive force on the ground.
“The FSA have their own battle to fight with the regime. They have their hands full. But they have a situation in Deir Ezzor where their forces are besieged by ISIS,” says Riad Kahwaji, head of the Dubai thinktank Inegma. “They are in a fix over there, and they don’t know how to get themselves out of it. They will be hoping that what ISIS did in Iraq will get them more international involvement in combatting this group.”
For the Assad regime, there are gains to be made from this fresh round of rebel infighting.
“ISIS has largely withdrawn from the western areas where the regime is focusing its attacks,” Lamrani says. “They’re not in Idlib, Latakia or western Aleppo. They only really come into contact with the regime in eastern Aleppo and in Deir Ezzor. And they have little units on the ground elsewhere, but that doesn’t effect the balance at all.”
In Syria itself, ISIS’s preeminent focus continues to be the consolidation of its territorial control and fighting other rebel forces. Fighting the government represents minimal strategic value to the group.
“I expect the Syrian government will be happy to leave ISIS and other military groups to fight it out in the east and northeast,” says Charles Lister, a visiting fellow and Syria specialist at the Brookings Doha Center. “After all, doing so only serves to further weaken the overall opposition to the government in Damascus.”
Lamrani calls this week’s Iraq push “hugely beneficial” to the Syrian regime, due to the infighting it has caused, drawing a tremendous amount of resources from the rebel side.
“This doesn’t mean ISIS and the regime are in alliance,” he says, “but as long as ISIS is focusing on the east, I don’t think Assad will be too keen on going after them. They are more focused on their offenses in Idlib and Hama. The regime is happy letting the rebels massacre each other, especially in Deir Ezzor.”
Meanwhile, Assad’s most important ally, Iran, is likely to intervene through Prime Minister Nuri al-Maliki and the Iraqi government, rather than asking Assad to do anything substantial. “Iran understands that the regime already has its hands full,” he says.
Kahwaji says Assad will also “take advantage of what happened in Iraq to once again proclaim that he is on the front lines of the war on terrorism.” It’s a case made stronger by the past week of events, which puts Syria next to the epicenter of a global terrorist threat.