As ISIS Falls, Border Battles Loom

Photo: John Moore/Getty

The U.S.-led military campaign against ISIS in Iraq and Syria appears to be nearing its end. In Mosul, Iraqi military forces are now pushing into ISIS’s last pocket of resistance in the Old City as allied militias cut off ISIS forces near Tal Afar. In Syria, the Syrian Democratic Forces (SDF) have encircled the ISIS “capital” in Raqqa and pushed into the city proper with U.S.-led coalition support.

However, as ISIS’ territorial footprint shrinks, a new battle for control over liberated areas is brewing. Forces aligned with the U.S.-led coalition are not the only players fighting ISIS. Russia, Turkey, the Syrian government, the Iraqi central government, Iran-backed militias, and a mix of Kurdish militias are just some of groups angling to stake their claim to the lands ISIS leaves behind.

Two strategic areas along the Iraqi-Syrian border – Sinjar in northwestern Iraq and the regions of Raqqa and Deir al Zour in eastern Syria – are set to play a vital role in this burgeoning power struggle. As these disparate forces operate in ever closer proximity, who stands to gain after ISIS’ fall, and how far is the U.S. willing to go to assert its interests in eastern Syria and northwestern Iraq?

Russian cruise missile strikes launched from warships in the Mediterranean against ISIS targets near Palmyra on Friday are only the latest in a series of escalating tensions between U.S.-backed and Syrian government-aligned forces in eastern Syria. U.S.-led coalition troops stationed on the southeastern Syrian border with Iraq in al Tanf have shot down two approaching Iranian and Syrian regime drones this month, and on June 18, a U.S. Navy F/A 18-E Super Hornet shot down a Syrian SU-22 bomber, which was attacking SDF and other coalition-allied units to the west of Raqqa.  

This spike in incidents is a reflection of eastern Syria’s strategic importance to both the Syrian regime of President Bashar al Assad and Iran. First, in the city of Deir al Zour, Assad’s forces have held out against ISIS fighters since 2014. Those troops only control two small enclaves, which must be resupplied by air, but their presence has been a useful thorn in ISIS’ side. Now, says Aron Lund, Syria expert and Fellow at the Century Foundation, Syrian regime forces must relieve this bastion in Deir al Zour, unless they want to “continue to waste the enormous amount of resources that they’ve sunk into the city.” Deir al Zour is also the administrative capital of the surrounding region so taking it from ISIS would give Assad a valuable base of operations from which to project authority in the province.

For Iran, it is the border regions south and east of Deir al Zour which hold the most value. If Tehran can establish control over one or more major border crossings on the Syria-Iraq border, the Islamic Republic will finally have a secure land route from Iran to Lebanon and the Mediterranean through friendly territory in Iraq and Syria. According to Michael Knights, a Lafer Fellow at the Washington Institute, this route “would be very useful in the event that Iran’s allies cannot use airports in Lebanon and Syria during a future war.” It would also have symbolic value as a public victory in Tehran’s regional competition against Sunni Arab states led by Saudi Arabia, as well as the United States.

This is why Iran-backed militias have continually pushed so close to U.S. troops – and the local Arab allies they have been training to fight ISIS – garrisoned in al Tanf. It is also why regime forces are pushing towards Abu Kamal to the north of al Tanf, which is the last unclaimed major border crossing in eastern Syria.

In a press conference on Friday, the spokesman for the U.S.-led anti-ISIS Operation Inherent Resolve appeared to accept Syrian regime and Iranian-backed efforts to take Abu Kamal, saying, “if they want to fight ISIS in Abu Kamal and have the capacity to do so…that would be welcome.” This statement could be a sign that the U.S. is willing to accept further regime advances towards Deir al Zour from Palmyra in central Syria and the city of al Dumayr in eastern rural Damascus. However, the downing of the Syrian warplane in western Raqqa and Iranian and Syrian drones near al Tanf suggests that Washington will continue to draw the line on Syrian and Iranian encroachment in the coalition’s areas of operations around Raqqa and al Tanf, or attacks on local allies like the SDF.

Similar dynamics are raising the risk of new conflict along the Syrian border in northwestern Iraq, particularly near the Iraqi region of Sinjar. There, as ISIS forces face defeat in Mosul and encirclement in Tal Afar to the west of Mosul, a dizzying array of local and regional actors are positioned to vie for influence. The local population of Sinjar is primarily Yazidi – an ancient religious group in northern Iraq – and has suffered grievously at the hands of ISIS fighters. Before ISIS’ conquest of the area in 2014, Sinjar was controlled by the Iraqi Kurdistan Regional Government (KRG) and secured by the Kurdish Peshmerga.

However, after ISIS routed Peshmerga troops in 2014, fighters from the Turkish Kurdistan Worker’s Party (PKK) helped defend the Yazidi population. Now, the PKK has established a presence in Sinjar and along the northeast Syrian border where their sister organization, the U.S.-backed Syrian Kurdish People’s Protection Units (YPG) hold power. At the same time, Iraqi paramilitary Popular Mobilization Forces (PMF) militias – many of them backed by Iran – have looped around Tal Afar to enter the Sinjar region and establish a presence along the Syrian border, positioning themselves well to establish a border linkage with either the Assad regime or YPG-controlled Syria, which has deep economic ties to Damascus.

With all these groups operating in the same area – and training their own local militias – the potential for new conflict is high. The potential for a conflict that drags in regional powers is also increasing. Turkey, for instance, is closely linked with the KRG and adamantly opposed to the PKK and YPG establishing a presence in Sinjar and on the Turkish border with Iraq; Iraq would like to reestablish control over the previously KRG-controlled region; and Iran is intent on expanding the presence of its proxy militias in the area.

One common denominator in both of these critical flashpoints is the United States. U.S. coalition and allied forces are at the vanguard of anti-ISIS operations in both border regions, giving Washington the military leverage to shape the political map post-ISIS. So far, however, policymakers have given little indication as to what America’s strategy in the region will be after the battle against ISIS is complete.

View our expert commentary on this topic:

The Complex State of Play in Eastern Syria, by Aron Lund, a Fellow at The Century Foundation

The Fight for the Northern Iraq-Syria Border, by Michael Knights, the Lafer Fellow at the Washington Institute for Near East Policy.

Fritz Lodge is a Middle East and international economics analyst at The Cipher Brief. Follow him on Twitter @FritzLodge.