Iran and its proxies have already begun to shape post-ISIS Syria, and eastern Syria is the most important theater. Yet recent events show that Iranian-backed forces advancing there will inevitability collide with two hostile forces, and compete with one of them. The first lies south in the al-Tanf border area, where US special forces and their Arab partners continue to take ground from the Islamic State (ISIS, ISIL, or Daesh). The second force lies to the north, where the US-backed Syrian Democratic Forces (SDF) could follow their current Raqqa offensive with an attack on ISIS in Deir Ezzor. Iran will come under great pressure to try to counter these advances. If it and the United States stay the course in the current atmosphere of strategic confusion, it is difficult to see how they can avoid a conflict, and it is still unclear whether US policy is ready for one.
Sporadic US air strikes and Iranian-backed ground maneuvers may look like haphazard tactics in a desert wasteland, yet there is in fact much at stake in these territories for Iran, Hezbollah, and the Syrian regime. Iran must prevent the control of eastern Syria by US-backed forces in order to protects its dominance in Iraq, the survival of the Syrian regime, and Hezbollah’s strategic depth. Additionally, while analysts continue to highlight that the regime is too weak to control all of Syria, the regime itself appears to disagree. It has its sights set on the water and oil resources of eastern Syria, without which it would struggle to survive. The regime has every interest in preventing US-backed Arab or Kurdish forces from securing this territory.
The regime itself seems too weak and preoccupied to threaten the US-led coalition in al-Tanf. However, Iran is far more capable, with large reserves of (proxy) manpower and little tolerance for a US-backed de facto statelet in its Syrian client’s territory. It is more likely that Iran, acting through its local proxies, would test the coalition’s resolve through increasing provocations. If so, it would calculate that the United States would back down to avoid serious escalation, thereby curtailing its territorial advances. Whether that is a sound calculation depends on the United States’ ultimate goals in eastern Syria and the importance it places on them in the face of the likely array of Iranian threats.
On May 17, the IRCG-affiliated Fars News reported that Hezbollah had deployed three thousand forces in the eastern Syrian desert, most of which were redeployed from the highly strategic Zabadani, Madhaya, and Serghaya regions near Damascus and the Lebanon border. It is unclear which Hezbollah units were deployed, but if indeed they were taken from those key areas they may be the elite Radwan units, apparently deployed among pro-regime militias. Radwan forces specialize in raids and small-unit tactics, and were critical to the regime’s tactical counteroffensives during the battle of Aleppo.
Hezbollah’s desert deployment is likely aimed at constraining the coalition’s operations by leaving as large a military footprint as possible before “an imminent large-scale operation against ISIS in Central Syria,” according to pro-Iranian regime news outlet ABNA. In principle, these deployments seem aimed at preempting and complicating US-led operations, rather than seeking a direct confrontation, and while expanding Iran and Assad’s control in central Syria. The militias would lose a direct confrontation with US forces, but the question is whether the United States is willing to take them on. If the US chooses not to take them head on, the weaker forces can indeed make things difficult. For example, last week regime forces managed to preempt US-backed fighters’ expansion north of al-Tanf simply by taking the ISIS territory itself first. The US can either force them to withdraw, or call off its mission. Neither option is especially attractive: one carries the risk of war, the other of humiliation if not complication of the counter-ISIS mission.
In the north, Iranian-backed efforts are less obvious. In Iraq, Popular Mobilization Forces (PMF) have made steady gains against ISIS to secure the Iraq-Syria border in Operation Mohammed Rasullah the Second. For these Shia-dominated forces, the goal is at a minimum to cut ISIS’ cross border supply lines. However, the mission’s limits are unclear, particularly given Iran’s influence over the PMF. Certain pro-Iranian elements may go on to disrupt the US-backed SDF’s anti-ISIS advances in eastern Syria, perhaps under the pretext of (and indeed through) fighting ISIS, and through more preemptive land grabs, for example. In fact, factions like Liwa Abu al-Fadl al-Abbas are already operating across the border despite US threats. PMF deputy commander, Abu Mahdi al-Muhandis, rejected these threats, affirming that there “has to be a road linking the two countries.” Last week, activists reported that PMF units had seized two villages in southern Hasakah in Syria, a province north of Deir Ezzor. And most recently, a Syrian Army delegation is holding talks in Baghdad to discuss border security.
The most confusing actor in all this is the United States itself. Its official mission in Syria remains defeating ISIS. Its aggressive actions against Iran in the eastern desert, such as attacking Iranian-backed forces and deploying long-range artillery, could merely be measures taken by field commanders to protect US forces conducting anti-ISIS missions. On the other hand, the Trump administration is deeply hostile to Iran, and key members of its national security team favor a more robust, long-term, US-military presence in Syria to contain Iran. Either theory could explain US action.
If the United States itself has no clear policy, Iran is left testing its limits or acting without any idea of its constraints and therefore dangerously. The administration has not explained how it plans to tackle the inevitable Iranian obstacle on the US advance into eastern Syria, so Iran cannot reliably gauge the scope and intensity of US commitment to this race. This makes an escalation, intentional or otherwise, much more likely. Escalation itself is not necessarily undesirable, but the Trump administration has not presented a clear case for it, and neither friend nor foe seem to know whether it has adopted it.
Faysal Itani is a senior fellow with the Atlantic Council’s Rafik Hariri Center for the Middle East.
Ali Marhoon is an intern at the Atlantic Council Rafik Hariri Center for the Middle East.