The overthrow of Bashar Assad’s brutal regime in Syria has seen the collapse of one of the cornerstones in Iran’s regional politics and the emergence of new power dynamics in the volatile region. The faultlines caused by Israel’s aggression in Gaza since Oct. 7, 2023, and more recently in Lebanon have shaken Iranian regional influence and destabilized its proxy networks.
For all practical purposes, Tehran has suffered an unprecedented blow to its desire for regional dominance. In a situation where Hezbollah – and, to an extent, Hamas – have become significantly ineffective, Syria came under the control of Sunni armed groups opposed to Assad’s Alawite regime. This effectively eliminated any elbow room for Iran-backed Shiite militia forces. Although Iran is currently likened to an octopus with its arms cut off, Tehran will definitely re-evaluate its defense doctrine, which is essentially based on its Axis of Resistance. The Houthis in Yemen, Hamas in Gaza, Hezbollah in Lebanon, Assad in Syria and militia groups in Iraq made up the opportunistically created Axis of Resistance, which gave Tehran strategic depth in the region. However, the scope for maneuvering by Iran will be limited, with an unpredictable and fiercely anti-Tehran new President of the United States, Donald Trump, set to begin his second term at the White House.
Tehran’s myth is far gone
In fact, it was Trump who had triggered the collapse of Iran’s proxy network during his first presidency. Within his “maximum pressure” policy framework, the U.S. in 2018 unilaterally withdrew from the Iran nuclear agreement, formally known as the Joint Comprehensive Plan of Action (JCPOA). Trump dealt the biggest blow to Tehran when he ordered the killing of Quds Force Commander Qasem Soleimani – the mastermind of controlling Iran’s proxy networks – in Baghdad in January 2020 in a drone strike.
Since the start of the Gaza war in October 2023, the U.S.’s all-weather ally Israel has dealt several crippling blows to Iran. Lebanese Hezbollah, the strongest pillar of Iran’s proxy network in terms of doctrinal and operational aspects, was weakened after Israel targetted the group with an unprecedented pager attack and separately killed its longtime leader Hassan Nasrallah and almost the entire executive cadre within a short time. After such losses, Hezbollah was forced to shrink up and withdraw its field support to Assad, which is said to be one of the reasons for the quick fall of the regime. Israel’s assassination of Hamas leader Ismail Haniyeh in Tehran and the elimination of his successor Yahya Sinwar further undermined the network.
With the collapse of the Assad regime, Tehran’s access to its proxy network in Lebanon and Palestine has been significantly restricted, a factor that will push Tehran back in regional politics. While Hamas has not announced a leader after Sinwar, Nasrallah’s successor, Naim Qassem, admitted that they lost their supply route from Syria with the fall of Assad. Qassem also underlined that the new Syrian administration should not be “judged,” indicating that the group has all but accepted the new geopolitical realities in the region.
Accept the reality
Some Iran-backed Iraqi militia groups within the Popular Mobilisation Forces (PMF), the state-sponsored Iraqi paramilitary units, have been operating in Syria on behalf of Iran since 2012. After opposition groups began marching towards Damascus on Nov. 27, the Iraqi Shiite militias made harsh statements and vowed to go to Syria to fight. However, their rhetoric instantly changed with the collapse of the regime on Dec. 8. In fact, PMF head Falih Al-Fayyadh said that Iraq is committed to supporting Syria’s stability and refraining from interfering in its internal affairs.
Given Tehran’s failure to mount a strong retaliation to the assassinations of Soleimani and Nasrallah, the Tehran government appears to be weak in responding adequately to possible assassinations targeting Iraqi militias. Iraqi militias remained less impactful than the Houthis in responding to Israel’s attacks on Gaza. This situation stems from their kingmaker status in the Iraqi government, giving them much to lose. Moreover, Iraqi Prime Minister Mohammad S. Al Sudani’s shuttle diplomacy and Iran’s defense doctrine – starting its borders one country away – were instrumental in this process.
Tehran is concerned that uncontrollable instability in Iraq would increase the risk to its borders and regime. However, even if Iran-backed Iraqi militias do not want a Sunni-dominated Syrian state, they may accept the new reality and not want to be part of an unpredictable adventure for now.
Being on the ropes
While Iran’s sphere of influence in the region has increased since the U.S. invasion of Iraq in 2003, the Iran-Iraq-Syria-Lebanon land corridor served as the main backbone of this sphere of influence and its logistics route. Moreover, the sudden fall of Assad’s regime and the inability of Iran’s proxy network to respond effectively to the regime’s collapse have severed this vital connection.
Consequently, Iran’s longstanding strategic partnership with the Assad regime and Hezbollah, along with its logistics network, appears to have ended. This disruption is also expected to significantly reduce the military support provided to Palestinian groups like Hamas and Islamic Jihad, which have relied on Damascus as a logistical hub.
Iran, which has been under intense pressure from Israel since October 2023, should closely monitor its capacity to intervene in Syria in the new period.
The Iranian supreme leader Ayatollah Khamenei has claimed that the current armed groups’ dominance in Syria will not last long. The convenience of the Syrian-Lebanese border for crossings, the Hezbollah factor, the crossing areas on the Syrian-Iraqi border and the intense Iranian influence in Iraq present an environment that Tehran will not easily give up.
However, Israel seeks to cut off the Lebanon-Syria connection. The new Syrian administration’s inactivity in Lebanon will also serve this purpose. Indeed, Syria’s de facto leader Ahmed al-Sharaa’s statement that they have ended Iran’s presence in Syria and that Tehran’s “expansionist project” is a threat to regional countries indicates that Syria will be quite painful for Iran.
In a geopolitical context where Hezbollah has been rendered ineffective, militias in Syria have retreated and Iraqi militias have remained silent, Tehran appears to have few operational allies left in the region, aside from the Houthis in Yemen.
However, Iran may seek to develop new engagements to create space for itself despite all the fractures and pressures. Strengthening the Axis of Resistance and focusing on regional ties to withstand possible pressure from the Trump administration would be the main concern for Iran.
Iran should prepare for Trump’s second term. Considering that Israel’s campaign against the Axis is not yet over, Tehran should force a deal with the U.S. to provide better protection from further Israeli aggression. In this option, Iran will likely try to reassess its defense doctrine based on the Axis of resistance and may also bring forward its nuclear and missile programs to strengthen the regime’s security. Alternatively, Iran may close up itself for a while to hinder the weakening of its militia capabilities in the region and to emerge with minimal damage from the unpredictability of Trump’s term. However, if the pressure on Iran continues, the Gulf countries may become the easiest targets of Iranian aggression despite this being a weak option. In this scenario, it would not be difficult to instrumentalize the Houthis and Iraqi militia groups. However, this situation would not only lead to Iran’s weakening influence in the Middle East but also lead to its further isolation by confronting the Gulf countries.