America’s Syria Withdrawal Has a New Reckoning: Iran

The official story was always about ISIS. The thousand or so American troops stationed across northeastern Syria and at the al-Tanf garrison near the Jordanian-Iraqi border were there, Washington insisted, to suppress what remained of the Islamic State’s territorial ambitions. When the Trump administration formalized its withdrawal plan in January and began moving forces out in February, that was the rationale it offered publicly: Assad was gone, Damascus had joined the anti-ISIS coalition, mission largely accomplished.However, was it ever really just about ISIS? Now that the United States is at war with Iran, that question is pressing hard against the official record. The quiet second purpose of America’s Syria footprint: containing, monitoring, and obstructing Iranian power projection across the Levant, is receiving the scrutiny it long deserved.Pentagon officials over the years regularly coordinated with Israel’s top brass as Israeli fighter pilots exploited the United States-controlled airspace over al-Tanf to launch strikes on Iranian weapons shipments moving through Syria. The base had been quietly repurposed to monitor and geographically impede Iranian military expansion in coordination with Israel and Jordan. This mission stretched well beyond the legal authority underpinning its stated mandate.In 2019 congressional testimony, the first Trump administration’s Syria envoy, James Jeffrey, was unambiguous about the base’s true purpose. “What really concerns us more is Iranian power projection systems: long-range missiles, drones, radar systems, air defense capabilities,” Mr. Jeffrey said. “If they can be allowed to embed themselves in that country with long-range systems, they would be able to open a third front on Israel next to Lebanon and Gaza.”Yet, American forces withdrew entirely from al-Tanf on February 11, seventeen days before the United States and Israel launched Operation Epic Fury against Iran. The timing is not lost on anyone watching the region.Yet American forces withdrew entirely from al-Tanf on February 11, seventeen days before the United States and Israel launched Operation Epic Fury against Iran. The timing is not lost on anyone watching the region. Did Washington quietly surrender one of its most valuable pieces of leverage over Tehran — just as it was preparing to go to war with it?What al-Tanf Was Really ForAnalysts at the Foundation for Defense of Democracies argued at the time that the withdrawal was an own goal, that whatever progress Damascus had made, the al-Tanf mission remained a low-cost brake on Iranian weapons flows to Hezbollah that Washington chose to release.The administration’s defenders offered two counterpoints: that the new Syrian government had already disrupted Iran’s corridor through the country, and that forward-deployed troops in isolated desert outposts were targets, not assets, in a brewing war with Tehran. Both arguments have merit. Neither fully resolves the question of what America can no longer see, or stop, along that border.On that narrow tactical calculus, pulling troops before Iranian missiles started flying made sense. However, the broader strategic question is harder to answer cleanly. Iran’s land bridge to Hezbollah, running from Tehran through Baghdad to Damascus and Beirut, traversed exactly the territory American forces had been watching. One documented route passed directly through the al-Tanf crossing on the Syrian-Iraqi border and on toward Damascus. With al-Tanf now in Syrian Army hands and the northeastern bases vacated, that corridor’s monitoring architecture has been dismantled at the precise moment Iran has every incentive to begin reconstituting its proxy network.“Iran has not stopped attempting to transport weapons to Hezbollah through Syrian territory despite the fall of the Assad regime,” senior research analyst at the Foundation for Defense of Democracies focusing on Syria and United States foreign policy in the Middle East, Ahmad Sharawi, tells the New York Sun. “The United States presence at al-Tanf played a critical role in tracking and monitoring these transfers. Tehran exploits fragmentation and instability to advance its operations. In Syria’s current environment, Iran and its network are likely to view an American withdrawal as another gap they can exploit.”Other analysts see it differently.“United States forces in Syria have never been tasked with interdicting Iranian supply lines to Hezbollah, so removing the small contingent of 1,000 United States soldiers would have no effect on Iran’s supply capabilities,” Director of the Middle East Program at Defense Priorities, Rosemary Kelanic, tells the Sun. “The fall of Bashar al-Assad, an Iranian ally, was the more decisive factor in preventing Iran from using Syria as a corridor.”It is not an argument without merit. The new Syrian government has worked hard to stay out of the conflict, reinforcing its Lebanese border to prevent Hezbollah fighters from crossing into Syrian territory to evade Israeli operations. Those are not the moves of a government inclined to let Iran reconstitute supply lines on its soil.The ISIS WildcardThe withdrawal’s stated rationale — that Damascus can now handle the ISIS mission — is being tested in real time, and the early returns are mixed. ISIS activity across Syria increased sharply following Assad’s fall, rising to 294 attacks in 2024 from 121 the year prior. On December 13, 2025, two United States Army soldiers and one American civilian interpreter were killed in an ambush by a lone ISIS gunman near Palmyra in central SyriaSince Operation Epic Fury began, a mass prison break unfolded across northeastern Syria’s detention network — the collapse of the fragile security architecture around those facilities occurring precisely as American forces and the SDF redirected attention toward Iranian strikes. An internal memo distributed to European Union member states raised alarm that thousands, potentially the majority of those held at al-Hol camp, may have escaped. CENTCOM scrambled to move up to 7,000 ISIS detainees from Syrian facilities to secured locations in Iraq. This massive logistical undertaking underscored just how fragile the containment architecture had become the moment American attention shifted.“There is very little evidence that forces in Syria can contain ISIS independently,” Mr. Sharawi tells the Sun. “The Syrian government is still consolidating its security institutions, and those institutions remain undisciplined. ISIS thrives on these gaps and fragmented states, and a full United States withdrawal will only expedite their resurgence.”Hans-Jakob Schindler, senior director at the Counter Extremism Project, agrees the trajectory is troubling. “ISIS in Syria, which was able to conduct ever more attacks year-on-year over the past several years, is going to continue to grow,” he tells the Sun. “The withdrawal of a large part of the United States forces is one aspect that is likely going to enable this.”Ms. Kelanic, however, counters that the threat is better managed by those with the most skin in the game. “Regional actors like Turkey and Syria can effectively prevent an ISIS resurgence without United States boots on the ground,” she observes. “ISIS was always a bigger threat to local actors than to the United States; therefore, those actors have the strongest motivation to keep ISIS defeated.”A Gamble With No Easy VerdictThe Trump administration’s case for leaving Syria was, to many analysts, always coherent on paper. The caliphate was gone. Assad was gone. A new Damascus had joined the anti-ISIS coalition and wanted American diplomatic and economic support, not American boots. Forward bases in isolated desert terrain had become targets. The withdrawal was defensible — perhaps even inevitable.What was not anticipated, however, was the precise moment it would be completed. American forces finished leaving Syria just as the United States went to war with Iran, stripping the Levant of its forward intelligence architecture and its most direct brake on Iranian weapons flows at the moment Tehran’s proxies have every reason to reconstitute, reroute, and rearm. At the same time, ISIS, never fully dormant, is operating in an environment tailor-made for its resurrection: weakened state institutions, overwhelmed security forces, thousands of fighters and their families unaccounted for across a shattered detention network, and a region-wide war pulling every capable actor’s attention elsewhere.The question of whether the Syria withdrawal was a strategic error may not be answerable for years. The Kurdish-Damascus integration deal, hailed in January as a milestone for Syrian unity, remains fragile in implementation — and a breakdown would hand both ISIS and Iranian influence operations exactly the vacuum they need. “A conflict between the Kurdish community and the interim government would mean a significant destabilization of Syria, which in turn would further enable the ongoing growth of ISIS as well as Iranian influence operations,” Mr. Schindler warns.Whether Damascus holds, whether ISIS seizes the moment, whether Iran finds its corridor again, none of those answers will come from Washington. They will come from the ground in Syria, where America no longer has anyone directly standing on it. Whether Damascus holds, whether ISIS seizes the moment, whether Iran finds its corridor again, none of those answers will come from Washington. They will come from the ground in Syria, where America is in the final stages of ensuring it no longer has anyone there.

America’s Syria Withdrawal Has a New Reckoning: Iran

America’s Syria Withdrawal Has a New Reckoning: Iran

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