Iran: Biggest loser after Assad’s fall

Among the central factors that led to the ouster of Bashar al Assad was Iranian and Russian decisions not to intervene yet again to prop him up. While Syria’s trajectory remains highly uncertain, its post-Assad posture is likely to be inimical to both the countries.    

Tehran had long used Syria as vector to project influence in the region and marshalled significant resources and manpower to keep Assad in power when the Syrian civil war erupted in 2011.

Moscow similarly saw its ties with Assad as a source of regional influence, and its 2015 intervention in Syria was decisive in Assad maintaining his stranglehold on power.

But with Russia bogged down in Ukraine, and Iran — and its allies like Hezbollah — severely weakened by the post October 07, 2023 conflict with Israel, neither patron was willing to rescue Assad once again.

USIP’s Garrett Nada explains what Assad’s ouster means for Iran: 

The toppling of the Assad regime is a major loss for Iran, which has not been so isolated or vulnerable in the region since the 1980-1988 war with Iraq. Syria was Iran’s only close state ally in the Middle East. It was a frontline against Iran’s archenemy Israel and the linchpin of Tehran’s ability to project power in the Levant. For four decades, Syria was the main conduit for Iran’s supply of weapons and equipment to Hezbollah in Lebanon, which became the world’s most heavily armed non-state actor.

Iran’s extensive support to Assad during the Syrian civil war, which broke out in 2011, reflected the country’s importance for Tehran’s regional strategy. Iran deployed thousands of military advisers and troops, mobilized tens of thousands of foreign Shiite fighters from as far away as Afghanistan and Pakistan to bolster regime forces, and organized a new Syrian paramilitary and provided billions of dollars in aid. Iran’s efforts, coupled with Russian air support, helped keep Assad in control of much of Syria until late 2024.  

Iranian officials quickly accepted the fate of the Assad regime despite all the blood and treasure invested. “It is the Syrian people who must decide on the future of their country and its political and governmental system,” President Masoud Pezeshkian said on December 08, 2024.

Iran’s foreign ministry expressed a willingness to engage with a new government. “The Iranian and Syrian nations have always had long-standing and friendly relationship,” it said on December 08.

“It is expected that this relationship will continue with a wise and forward-looking approach by both nations, based on mutual interests and adherence to international legal obligations.”

Iran asked HTS to protect Shiite holy sites in Syria, and HTS confirmed that it would protect the Sayyida Zeinab shrine in Damascus.

Yet Iran’s future relationship with Syria is dubious. Many of the players poised to play key roles in the transition hold Iran responsible for propping up the brutal Assad regime.

“This new triumph, my brothers, marks a new chapter in the history of the region, a history fraught with dangers (that left) Syria as a playground for Iranian ambitions, spreading sectarianism, stirring corruption,” Abu Mohammed al-Jolani, the leader of Hayat Tahrir al Sham, said in his victory speech on December 08.

On the same day, Iran’s embassy in Damascus, previously evacuated, was vandalized and looted. Posters of the supreme leader and other Iranians were torn and discarded on the floor.

The fall of Assad may push Iran to reconsider its “forward defense” strategy. For decades, Iran has relied on the “Axis of Resistance,” including Syria and militia allies across region, to pressure Israel and deter strikes on Iranian soil. The goal was to keep conflicts far from Iran’s borders. But the axis already faced severe setbacks before Assad’s departure.

Israel significantly weakened both Hamas in Gaza and Hezbollah in Lebanon during the war that erupted after the Hamas-led October 07 terrorist attacks. Israeli forces killed senior leaders and thousands of fighters and degraded both groups’ abilities to wage war. Iran will face significant logistical challenges to resupplying Hezbollah without the Syrian land bridge.

Meanwhile, Iran lacks credible mechanisms to deter Israel. Tehran launched unprecedented direct attacks on Israel, one in April 2024 including 170 drones, at least 30 cruise missiles, and more than 120 ballistic missiles, and one in October 2024 including more than 180 ballistic missiles. But neither caused significant damage or dissuaded Israel from launching counterattacks, the second of which crippled Iran’s air defenses and damaged missile production capabilities.

The remaining members of the “Axis of Resistance” are not much help in terms of deterring Israel. The Houthis in Yemen have proven resilient despite attacks by the US and Israel but have only carried out sporadic long-range missile and drone attacks.

The Iraqi militias backed by Iran, such as Kataib Hezbollah and Harakat Hezbollah al Nujaba, are also relatively peripheral and have not caused much damage to Israeli targets.

With limited options, a growing number of Iranian officials have called for revising the country’s nuclear doctrine to allow the production of nuclear weapons. As of late 2024, Iran could produce enough highly enriched uranium to fuel one nuclear bomb in as little as one or two weeks.

Tehran would need several months or more than a year to assemble a warhead and marry it to a delivery system, such as a ballistic missile. But moving to weaponize would come with its own serious risks.