Michael Knights is the Jill and Jay Bernstein Senior Fellow at The Washington Institute and cofounder of the Militia Spotlight platform, which offers in-depth analysis of developments related to Iran-backed militias.
Brief Analysis
Tehran’s past efforts to reconstitute the group have passed through more difficult environments than post-Assad Syria, but an economical U.S.-led effort can complicate future smuggling efforts and further other counterterrorism goals in the process.
Although the collapse of Bashar al-Assad’s regime is certainly encouraging, this does not mean its former patron Iran will simply give up on using Syria as a corridor for reconstituting Hezbollah next door in Lebanon. Quite the opposite: Iranian arms smuggling has historically thrived in collapsed or weak state environments.
Consider Yemen, for example. Since the Houthis were placed under a targeted arms embargo in 2015 under UN Security Council Resolution 2216, Iran has built up the group’s arsenal of medium-range ballistic missiles, antishipping missiles, cruise missiles, long-range attack drones, explosive drone boats, surface-to-air missiles, and other advanced capabilities, while also smuggling in heavily subsidized fuel products. These supplies made it through a gauntlet of multinational monitoring, including a UN maritime trade inspection mechanism and maritime interdiction efforts by NATO and Gulf navies. Iran has also smuggled major arms systems (including liquid fuel oxidizers, missiles, drones, and sensors) through Oman, after which they were transported hundreds of miles through portions of Yemen held by anti-Houthi factions.
Potential Lines of Supply Post-Assad
Among Iran’s future options for sending materiel to Hezbollah, four possibilities stand out:
Continued overland truck transport through Iraq, across central Syria, and into Lebanon.
Other overland routes: through Iraq, Jordan, and southern Syria, or through Iraq, Turkey, and northern Syria.
Maritime transport to Syria’s Mediterranean coast, truck transport to Lebanon.
Air transport into Syria, truck transport to Lebanon.
As Syria presumably reopens post-Assad, it will see an influx of people, vehicles, money, humanitarian aid, reconstruction supplies, and consumer goods, much of it via truck transport from neighboring states. Iran could easily use this influx to reconstitute both Hezbollah and its proxy factions in Syria. Iraq is governed by a cabal of pro-Iran militias that have full control of its border posts, highways, and airports. In Jordan, Iran has long sought to weaken the government’s control and turn the kingdom into a more amenable base for anti-Israel and anti-Western activities by manipulating sympathetic Jordanian/Palestinian elements and foreign elements. And in Syria, the post-Assad environment may not be particularly resistant to Iranian smuggling networks, which are well-funded and overlap with existing drug cartels. The Alawite-majority coastal areas that formed the core of the late regime could also function as a shorter line of supply to Hezbollah, with contraband hidden within aid and reconstruction shipments sent to post-ceasefire Lebanon.
In addition, Iran has shown no qualms about making tactical arrangements with Sunni jihadist groups in the past (e.g., al-Qaeda and the Taliban), so it may choose to adopt this tactic in post-Assad Syria, where regime materiel is increasingly at risk of being seized by the Islamic State (IS). Assad’s military has fallen apart and no one knows how much of its arsenal is being gathered up by IS. Even if other factions seize the bulk of it, IS elements could try to buy it from them in the coming months. The northern and southern rebel forces that converged on Damascus over the past two weeks—most prominently Hayat Tahrir al-Sham (HTS)—include an unknown but significant number of U.S.-designated terrorist elements that have previously flitted between fighting IS and sharing resources with it.
Extend the U.S. Presence
Given this multiplicity of risks, the United States should actively pursue a host of preventive measures with the help of other interested parties—namely, any countries that want to reduce terrorist influence in Syria and thereby expand their own activities there. First and foremost, officials in the Biden administration and/or incoming Trump administration should reassess the wisdom of prematurely withdrawing key facets of the local U.S. military presence.
In Iraq, al-Asad Air Base is well-positioned to keep watch over IS elements and provide critical basing support to broader counterterrorism and countersmuggling efforts. Baghdad has ample reason to extend America’s stay at al-Asad, since it has concerns of its own about an IS resurgence and the rise of other Sunni jihadist factions in post-Assad Syria. Although the U.S.-Iraq Higher Military Commission previously envisioned closing this base in late 2025, the new situation next door merits a rethink.
Al-Tanf base in Syria, resupplied through Jordan, has also proven to be a very inexpensive and useful point of access for keeping an eye on southern and central Syria. Likewise, the existing U.S. Special Operations outposts along the Euphrates River are ideally placed to not only support various counterterrorism operations in Syria, but also monitor Iranian and proxy militia activities in that corridor. Ultimately, they may be required to prevent violent Sunni Arab extremist factions from overrunning the Kurdish elements that have been so crucial to the U.S. counterterrorism mission on the ground.
Authorities, Access, and Partnerships
Of course, monitoring, preventing, and potentially targeting Iranian-led smuggling to Hezbollah is not just a function of military presence—it also requires a deliberate legal and policy architecture to back it up. In Syria, the counter-IS mission has robust backing through UN measures such as Security Council Resolution 2249 (2015), which empowered states to “take all necessary measures” to reduce the IS threat. Yet the main U.S. mechanism—the 2001 Authorization for Use of Military Force (AUMF)—is a narrow and rapidly deteriorating source of authority for targeting al-Qaeda and “associated forces.” HTS might still qualify for this label despite renouncing its al-Qaeda roots—especially if elements of the group try to get weapons into the hands of global terrorist entities like IS and/or Hezbollah. (The State Department designation of HTS as a Foreign Terrorist Organization is separate from the issue of authorizing military action in Syria and will be fully discussed in a forthcoming PolicyWatch.)
In light of these complexities and Syria’s shifting environment, U.S. officials and Congress should initiate consultations on broadening the existing AUMF or passing a new one in 2025. The goal should be to authorize limited use of force against any U.S.-designated terrorist group in the Middle East if the president determines there is a need to act, including outside the narrow confines of imminent self-defense. Such a mechanism would facilitate U.S. freedom of action not just against groups like IS, al-Qaeda, Hamas, Palestinian Islamic Jihad, and the Houthis, but also against actors who might abet Iran’s effort to rearm Hezbollah (e.g., designated Iraqi militias). An “AUMF 2.0” could be especially useful if the next Syrian government revokes its consent for other countries to use force within its territory—an option that the West took away from the Assad regime due to its murderous behavior throughout the civil war.
Washington should also consider the following steps, with significant burden-sharing from NATO and regional partners:
Enlarge the Combined Special Operations Joint Task Force-Levant (CSOJTF-L) and broaden its mission, to include elements focused on non-IS threats and to support U.S. leadership of the new Lebanon ceasefire monitoring effort, part of which entails preventing Hezbollah’s military reconstitution. The United States also needs to bolster its intelligence, surveillance, and reconnaissance assets dedicated to these missions in Syria.
Strengthen CSOJTF-L at its Syrian points of presence. This could include new temporary patrol bases between al-Tanf and the bases that the Kurdish-ledSyrian Democratic Forces (SDF) have established in Abu Kamal and Deir al-Zour city. These patrol bases could be American or multinational—for example, Britain, France, Jordan, and the United Arab Emirates may be willing to quietly contribute special operations units to the mission. To preserve their main partner on the ground, the United States and France could also help the SDF by interposing ground and air patrols between them and Turkish-backed forces, thereby maintaining an uneasy peace in the area. (U.S. options regarding the SDF will be discussed more fully in a forthcoming PolicyWatch.)
Build out Jordanian counternarcotics cooperation. This will pay dividends due to the extensive overlap between Iran-backed narcotics trafficking and arms smuggling via Syria, both of which pose substantial threats to Jordan and the Gulf states.
Establish a new U.S. supply line to Syria. The main line of supply at present—from the Kurdistan Region of Iraq—might be increasingly vulnerable, so a secondary line should be established and tested between Jordan, al-Tanf, and the SDF-affiliated Democratic Autonomous Administration of North and East Syria (DAANES). This would provide redundancy while leaving Iraqi Kurdistan as the primary supply line.
Factor aerial and coastal traffic into a new monitoring regime. Under Assad, there was a clear “address” when international authorities needed to use Syrian ports and airports for aid deliveries or other nonmilitary purposes, but this is less apparent now. Accordingly, the United States and Israel should carefully reconsider how to monitor and limit Iran’s air and sea bridges to Syria and Lebanon. As part of this process, they could encourage Arab states to strongly pressure Syria’s transitional government on barring airspace access to Iranian flights bound for Syria or Lebanon.
Michael Knights is the Bernstein Senior Fellow at The Washington Institute and co-creator of its Militia Spotlight platform.
