The effort to expel Daesh, or ISIS, from its last bastion in all of Syria and Iraq, is reportedly nearing the end. But the organization appears to be ahead of the U.S-led coalition in preparing for the next chapter. The last battle over territory is occurring in the area most critical for the jihadist group’s prospects for future survival. Even as ISIS shifts fully from a group that holds and governs territory to an insurgency, the flawed campaign in its last stronghold may have planted the seeds for the group’s revival in the future.
On Sept. 9, 2017, the Syrian Democratic Forces announced the start of the battle to expel ISIS from the eastern Syrian province of Deir ez-Zor. The announcement came shortly after the Syrian regime and allied forces advanced toward the province to recapture areas on the western side of the Euphrates River. The regime declared victory against the group a month later, having cleared its side of the river from ISIS presence. While fighting ISIS the SDF and regime forces have continued to battle one another as well.
East of the river, the key struggle of U.S.-backed Syrian Kurdish forces against ISIS continues and the operation there has so far taken three times longer than the battle of Raqqa city and four months longer than the Mosul battle. This protracted campaign in the last territory held by ISIS has laid bare several faults in the campaign against the jihadist organization. This border area is vital for the group’s future existence and operations, which makes its enduring defeat in these parts crucial for Iraq, Syria and beyond. But multiple factors complicate fighting around the Euphrates River and could undermine the possibility of such an enduring defeat.
A Complex Theater
The battle is continuing in the area where the Euphrates River meets the Syrian-Iraqi borders. Each side of the river is controlled by rival forces in accordance with the demarcation line that the United States and Russia agreed on in the province last year. The regime and its allies control the western side of the river and a few villages east of the river in the provincial capital. Meanwhile, U.S. operations are occurring in a small area on the east side of the Euphrates.
The triangle around the river and the borders has created a flawed security architecture, which leaves room for ISIS to move and operate. This is because none of the forces on the two sides of the river has control over every boundary. Washington and Moscow often communicate with each other in eastern Syria. The two could agree to allow one force or coalition to control the area, which would make it easier to police and deal with emerging threats.
The complex security arrangement has sometimes led Iraq, which has ties with both coalitions, to strike inside Syria, where the United States cannot. Iraq’s increased role in Syria or near the border is a product of border security issues. Last month, Iraqi authorities warned that hundreds of ISIS fighters were preparing to launch attacks from Syria into Anbar after signs emerged that the group intended to recapture towns in western Iraq. Such patterns likely will continue, even after the expulsion of ISIS from its last stronghold in Deir ez-Zor.
Iraqi militias backed by Iran, want a dominant role in securing the Iraqi-Syrian borders. Iranian-backed forces inside Syria seek the same. However, the United States’ strategy in eastern Syria is predicated on weakening the Iranian presence in the country and along the borders. Given these dynamics, ISIS will likely benefit from the regional and international rivalry in an area that it arguably knows better than any other force.
Another factor that could enable future ISIS activity in the area is the demographic composition of the force now in control of Deir ez-Zor. Kurdish commanders lead the force, but the fighters are mostly poorly trained and ill-equipped locals with little experience fighting ISIS. Local forces that had fought ISIS before did not join the battle to reclaim Deir ez-Zor. Also, unlike Raqqa and al-Hasakah, Deir ez-Zor has almost no Kurdish population. This scenario leaves room for ISIS to attack or infiltrate these forces, as it did in similar circumstances in Iraq; last July, tribal chiefs in Salah ad-Din complained that ISIS re-emerged and moved without impunity at night.
Where ISIS Could Go to Ground
The region on both sides of the Syrian-Iraqi border is a strategic sanctuary for ISIS. The group will use an archipelago of desert areas, river valleys, rural towns and roads to operate and hide. The desert areas near Mosul, Anbar and Deir ez-Zor give ISIS access to at least seven key provinces in both Iraq and Syria, and potentially to Jordan and Saudi Arabia. These areas, as recent confessions by senior ISIS commander Abu Abd al-Haq al-Iraqi revealed, were seen as vital for the group’s survival even as the militants took over one-third of Iraq and nearly half of Syria in 2014.
This meant that ISIS worked early on to build the infrastructure for its hideouts, including tunnels, training camps, and weapons depots. The battle in this area could take up to two more months. But as ISIS shifts into a full insurgency, this region will be critical to the group’s survival and jihadist legitimacy. Much will depend on whether the military defeat of ISIS in the towns and cities near the borders will translate into enduring defeat.
It is in this region where ISIS will arguably either die or re-emerge. But all the signs so far indicate that ISIS is poised to sustain a long-term insurgency against its disparate enemies in Iraq and Syria. Therefore, the US.-led coalition appears less prepared to secure the borders and eradicate the group. ISIS is devolving, and this process will likely result in the jihadist entity assuming a new form.
Hassan Hassan is a Syrian analyst focusing on militant Islam, nonviolent extremism, and geopolitics in the Middle East. He is a contributing writer at The Atlantic, a senior fellow at the Tahrir Institute for Middle East Policy, and the co-author of “ISIS: Inside the Army of Terror” (2015).