Among the central factors that led to the ouster of Syrian dictator Bashar al Assad was Iran’s and Russia’s decisions to not intervene yet again to prop him up. 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 7 conflict with Israel, neither patron was willing to rescue Assad once again. While Syria’s trajectory remains highly uncertain, its post-Assad posture is likely to be inimical to Russia’s and Iran’s interests.
USIP’s Garrett Nada explains what Assad’s ouster means for Iran.
Nada: 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, 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 8. 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 8. “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 8. 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 7, 2023 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 U.S. 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.
The following is a compendium of reactions from Iranian officials to Assad's ouster.
Reactions from Iran
Supreme Leader Ayatollah Ali Khamenei
Dec. 11, 2024: “There should be no doubt that what happened in Syria was the result of a joint American-Zionist plot.
“Yes, a neighboring state of Syria clearly played a role in this matter and continues to do so — everyone can see that. But the main conspirator, the main planner, and the command center lie in America and the Zionist regime. We have indications that leave no room for doubt about this conclusion.
“By God’s grace, the scope of the Resistance will encompass the entire region more than ever. This is what the Resistance Front is, the more pressure you apply, the stronger it becomes; the more crimes you commit, the more motivated it becomes; the more you fight them, the more expanded it becomes.”
“I tell you that By God’s grace, Iran is strong and powerful and will become more powerful. By God’s grace, the occupied territories in Syria will be liberated by the brave Syrian youth. Do not doubt that this will happen. The US will also be expelled from the region by the Resistance Front.
“Some seek territorial occupation in northern or southern Syria, while the US aims to secure its foothold in the region. These are their goals, but time will prove that God willing, none of these objectives will be achieved.”
“Resistance is not a hardware system to be broken; it is a belief, a doctrine that grows stronger under pressure.
“We helped the Syrian government, but before that, the Syrian government gave us vital help at a critical juncture [during the Iran-Iraq War]. Most people don’t know this.”
“The Resistance will prevail, and the region’s future belongs to its determined people.”
President Masoud Pezeshkian
Dec. 8, 2024: “It is the Syrian people who must decide on the future of their country and its political and governmental system.
He expressed hope that the conflict in Syria would end “so that the Syrian people will be able to decide their own destiny in a calm atmosphere free from any violence, anxiety or destructive external intervention.”
Ministry of Foreign Affairs
Dec. 8, 2024: “The Ministry of Foreign Affairs of the Islamic Republic of Iran, considering recent developments in Syria, reiterates Iran's principled stance on respecting Syria’s unity, national sovereignty, and territorial integrity, emphasizing that determining Syria’s future and making decisions about its destiny are solely the responsibility of the Syrian people, without any destructive interference or external imposition. Achieving this requires the immediate cessation of military conflicts, the prevention of terrorist activities, and the initiation of national dialogue involving all segments of Syrian society to establish an inclusive governance structure that represents all Syrians.
“The Islamic Republic of Iran continues to support international mechanisms, particularly UN Security Council Resolution 2254, in pursuing the political process in Syria. The Islamic Republic also maintains constructive engagement with the United Nations in this regard.
“In this critical period of Syria's history, ensuring the security of all Syrian citizens and foreign nationals, preserving the sanctity of religious sites, and safeguarding diplomatic and consular facilities in accordance with international legal principles are of utmost importance.
“The Iranian and Syrian nations have always had long-standing and friendly relationship. 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.
“The Islamic Republic of Iran, emphasizing Syria's position as an important and influential country in West Asia, will spare no effort to help establish security and stability in Syria. To this end, it will continue consultations with all influential parties, especially those in the region.
“It is evident that the Islamic Republic of Iran will closely monitor developments in Syria and the region. Taking into account the actions and conduct of key players in Syria’s political and security landscape, the Islamic Republic of Iran will adopt proportionate approaches and positions.”
Foreign Minister Seyyed Abbas Araghchi
Dec. 8, 2024: Tehran “has spoken to parties” about ensuring the safety of Iran’s embassy and Shiite shrines.
“What caught us off guard was, one, the inability of Syria’s army to confront the movement and, second, the speed of developments.”
Assad “seemed surprised and voiced complaints about the behavior of his army.”
“There was no proper analysis of the Syrian army, even within the Syrian government. In my view, the army has become a ‘prisoner of psychological warfare.”
“The resistance front has been facing significant challenges for over a year,” but it “will prevail regardless of circumstances.”
Islamic Revolutionary Guards Corps Commander Hossein Salami
Dec. 10, 2024: "We have not been weakened and Iran's power has not diminished.
"The overthrow of the Zionist regime (Israel) is not off the agenda.”
Government Spokesperson Fatemeh Mohajerani
Dec. 10, 2024: Tehran is monitoring the behavior of the rebel group and “their distance from the Zionist regime is one of the factors that is important to us.”
“We have had longstanding relations with Syria, in terms of both culture and civilization. Our traders would travel to the Levant from much older times, so our ties with Syria have a long history. We hope that what is ahead is what is good for the people of Syria and we wish them the best.”
“Over the past three days, 4,000 Iranian citizens returned to Iran” from Syria, she said. Tehran would continue evacuating citizens “until the departure of the last Iranian.”
Hezbollah
Member of Parliament Hassan Fadlallah
Dec. 9, 2024: He described “developments in Syria as a significant and dangerous turning point.”
He emphasized the “need for careful evaluation away from public platforms, noting that despite the severity of the events, Hezbollah and its resistance remain steadfast, drawing strength from their faith, people and resilience.”
“No matter how critical the situation in Syria becomes, it cannot weaken us. Our strength comes from our faith, our people and our steadfastness.”
Houthis
Spokesperson and Member of the Houthi Political Bureau Mohammed al Bukhaiti
Dec. 9, 2024: “Our military operations in support of Gaza are ongoing and will not deviate from the compass of hostility that governs our jihad against the enemies of the nation. If the Al-Nusra Front moves to confront the Israeli aggression against Syria, we will be the first to support it.”
Hamas
Dec. 9, 2024: “The Islamic Resistance Movement Hamas congratulates the brotherly Syrian people on their success in achieving their aspirations for freedom and justice.
“We call on all segments of the Syrian people to unite, strengthen national solidarity, and rise above the pains of the past.
“Syria will continue its historic and pivotal role in supporting the Palestinian people and their resistance to achieve the goals of their just cause, while consolidating Syria's leading role within the Arab and Islamic nations, as well as on the regional and international levels.”
Iraqi Militias
Kataib Hezbollah
Dec. 10, 2024: “What the Syrian army has presented is a model of legendary steadfastness over decades, and that even if the problem is in its leadership, as is the case with other Arab armies, it will remain in the memory of the honorable people of the nation, and we hope that it will return to practicing its national role, even if after a while.
“The criminal essence of Al-Nusra and ISIS will not change no matter how much they pretend to be humane in front of the cameras, and the two countries that support these gangs are the ones who bear responsibility for any attack on the followers of the Ahl al-Bayt or transgression against their sanctities, as they know what that means, as they have experienced it before.
“We are monitoring the situation inside Syria, and we are waiting for the emergence of parties with which we can reach an understanding on the basis of resistance and the Palestinian cause, and rejecting those involved in shedding the blood of the weak and innocent, and preserving the national balance in Syria.”
Harakat Hezbollah al Nujaba
Dec. 10, 2024: “What happened in Syria was not spontaneous, and this occurred while the axis of support for Gaza was preoccupied, where an operations room was set up in Turkey to manage the destruction under British planning and with intelligence participation from NATO and the Zionist entity. This support and planning involved the use of satellites and drones to track the movements and locations of Syrian forces. The same operations room is currently working to destabilize Iraq, this time under British leadership, but from Baghdad, not from outside the borders. It is strange to give such great attention to the Iraqi borders while neglecting the focus on the internal threat! Yes, securing our Iraqi borders is important, but we should not be deceived and ignore the real source of danger within the capital, central and southern regions, as well as our western and northern areas, because this division is how the destructive conspiracy is being spread, each according to its role. This time, the conspiracy will come from within, not from beyond the borders.
“Secure the borders, and turn your attention to the sources of danger, and you will find those demanding the division of Iraq, coinciding with the activation of the U.S. Embassy (the "Embassy of Evil") to mobilize its agents, attempting to disrupt the internal situation. Then, targeting programs for Iraq will follow. Those following the developments will understand the price that the Zionist has gained for his support—he has been allowed to infiltrate Syrian territory and create a federation in Suwayda as a precursor to a future referendum for secession and joining (Israel), including villages along the Palestinian border. The Zionist entity is also working to remove all heavy and strategic weapons from Syria using its own methods, and the new leaders are providing guarantees for moving toward normalization in the future. So, act before the catastrophe occurs.”
Kataib Sayyad al Shuhada
Dec. 10, 2024: “Our position regarding the turbulent regional situation is based on the foundation of our national security and the primary issues of the nation, foremost of which is the Palestinian cause and the sacred sites. Any threat or weakening of these fundamental principles will undoubtedly compel us to take the necessary and appropriate actions.
“Iraq today, with its security forces, resilience, resistance, and people, is stronger and more prepared than ever to move forward in maintaining the safety and security of our homeland, people, and sacred sites.
“We salute the high national stance and discipline of the heroic Iraqi resistance fighters, who have proven once again that they are loyal sons of the state and defenders of its dignity, especially when it comes to strategic decisions.”