Is a regional war between Israel and Iran inevitable?

On 27 September, Israel levelled several high-rise apartment buildings in the Lebanese capital.

Felt dozens of kilometres away, these Israeli airstrikes produced the largest explosions in Beirut since the current wave of Hezbollah-Israel hostilities began almost a year ago.

By targeting Hezbollah’s Secretary-General Hassan Nasrallah and other leaders in the Lebanese party, Tel Aviv’s military strikes dangerously escalated the region’s conflict dynamics.

The following day, Hezbollah confirmed Israel’s killing of Nasrallah. The group announced that Nasrallah had “joined his great, immortal martyr comrades whose path he led for nearly 30 years”. Israel assassinating this larger-than-life leader was undoubtedly an immense blow to Hezbollah and its regional allies.

In terms of its impact on the Arab world, some have compared Nasrallah’s killing to the defeat of Egypt’s Gamal Abdel Nasser in 1967. Nonetheless, since Israel assassinated Nasrallah, the Lebanese organisation has attempted to project continuity, in terms of both its leadership and decades-long armed struggle against Israel.

Many Israeli officials and citizens have cheered Nasrallah’s death. In the words of Prime Minister Benjamin Netanyahu, Israel “settled the account” with a “mass murderer”. Israel’s leader said that Nasrallah “wasn’t another terrorist; he was the terrorist,” and “the central engine of Iran’s axis of evil”.

US President Joe Biden and Vice President Kamala Harris called Nasrallah’s killing a “measure of justice”.

There has also been celebration in north-western Syria’s rebel-controlled Idlib governorate, where much hatred for Hezbollah still exists due to the group’s intense intervention in the Syrian crisis, beginning with the 2013 battle for Qusayr.

Iranian vulnerabilities in the Middle East

After the Trump administration ordered the killing of Iran’s Major General Qassem Soleimani in early 2020, the ‘Axis of Resistance’ underwent somewhat of a decentralisation of its command-and-control structure.

Veena Ali-Khan, a fellow at the Century Foundation who focuses on the Gulf and Yemen, believes that the Tehran-led coalition’s move toward a more horizontal structure likely played out this month in Lebanon.

“This gave Hezbollah far more influence over the other actors in terms of command-and-control. I think the Iranians thought this was an effective way for the groups to manage themselves to a certain extent. But I think the way nobody anticipated for Israel to go this far has in fact exposed the vulnerabilities of this strategy,” explained Ali-Khan in an interview with The New Arab.

How this void will be filled and how the Hezbollah-Israel conflict will evolve are not easy to predict. The head of Hezbollah’s executive council, Hashem Safieddine, and the organisation’s deputy secretary-general, Naim Qassem, are two leading Hezbollah figures who might replace Nasrallah. Yet, Hezbollah’s Shura Council will ultimately make this decision.

Regardless of who becomes Nasrallah’s successor, there is no reason to assume that either Hezbollah or Israel’s hostilities toward the other will cease any time soon. Calls from Western and Arab governments for a Hezbollah-Israel ceasefire will probably have no practical effect on the ground.

Unfortunately, the past nearly 12 months of attacks across the Lebanese-Israeli border have likely been just the beginning of a much larger conflict with the potential to engulf the wider region.

This is beyond disturbing given that Israeli airstrikes have killed or wounded more than 7,000 Lebanese citizens in the past two weeks while also, according to the country’s prime minister, displacing up to one million others.

Nasrallah’s killing is disastrous for Iran and the ‘Axis of Resistance’, of which Hezbollah has long been a linchpin. This assassination puts the Islamic Republic in a tough spot, leaving Tehran with no easy choices. Some of the advantages which the Iranians had in the months following the Hamas-led incursion into southern Israel on 7 October 2023 no longer seem in play.

“Tehran recognises that its deterrence will be shattered and that the Axis will suffer irreparable damage if Hezbollah is near eliminated. Yet, its options are unattractive as Iran cannot calibrate an attack on Israel that causes sufficient damage to deter Israel without handing Netanyahu a pretext to escalate matters further,” said Dr Trita Parsi, the executive vice president of the Quincy Institute for Responsible Statecraft, in an interview with TNA.

“Other members of the Axis may take action, but any action they take will likely lead to a full-scale war that they are not ready to fight,” he added.

Sharing this assessment, Ali-Khan told TNA that Iran must “carefully balance between responding in a way that reflects the gravity of Nasrallah’s assassination, while also not giving Israel an excuse to directly hit Iran”.

This has been a dilemma for the Islamic Republic ever since Israel’s war on Gaza began almost a year ago. But now, with President Masoud Pezeshkian attempting to ease friction between Iran and the West, the Iranians understand that a forceful response to Tel Aviv could jeopardise any potential for a revival of the nuclear deal in some form.

“Israel has effectively reversed what had been a post-7 October political equation in which Israel and Hamas, not to mention other Palestinians, had suffered significant setbacks with Iran and its core allies [not including Hamas] pocketing the benefits at virtually no cost,” Dr Hussein Ibish, a senior resident scholar at the Arab Gulf States Institute in Washington, told TNA.

In light of Tel Aviv delivering a massive blow to Hezbollah and the ‘Axis of Resistance’, Dr Ibish believes that Tehran’s primary strategic doctrine itself has taken a huge hit.

“At a minimum, it will take many years to rebuild Hezbollah, and the group may yet suffer additional losses as there is no sign of Israeli attacks ebbing any time in the near term. This is an unmitigated disaster for Hezbollah, Iran and their network,” he added.

“It’s also noteworthy that Israel’s series of stunning assassinations in Lebanon and Iran, and commando operations in Syria, could only have been conducted as a result of thorough intelligence penetration of the inner workings of Hezbollah and Iranian intelligence.”

Ali-Khan says that on the morale front, the 'Axis of Resistance' is at a critical crossroads.

“Israel’s willingness to push boundaries further than anyone anticipated has caught its enemies off-guard, complicating their future military calculations. Tel Aviv has shown it is prepared to go all the way, in contrast to Iran and Hezbollah, though escalating tensions, have been careful to avoid full-blown war,” she explained.

Hezbollah 'wounded but not defeated'

Although Israel has caused a tremendous amount of damage to Hezbollah, both in terms of its infrastructure and the resistance organisation’s morale, it would be naïve to believe that Tel Aviv has eliminated the threat that Hezbollah can pose to Israel.

As long as the resistance organisation can threaten Israel’s security in the north, the Israelis who had to leave their homes there will probably not be able to return there safely. In this sense, it seems unrealistic to conclude that the recent blows which Hezbollah has received will thwart the group from being able to deny Tel Aviv its strategic objective of returning displaced Israelis home.

Hezbollah has existed for decades and garnered high levels of support from segments of Lebanon’s society and it has its supporters in other Arab-Islamic countries too. It is doubtful that the killing of Nasrallah and other high-ranking leaders in the organisation, or Israel’s intense air strikes against targets in Beirut, will mark Hezbollah’s demise.

The party’s fighters will not lay down their arms and capitulate to Israel. After all, the conditions that made Hezbollah popular among certain Lebanese citizens still exist and, if anything, more Israeli brutality in Lebanon will play into the resistance group’s narratives.

“Losing its historic figurehead is a symbolic blow, but these attacks do not amount to a defeat. Hezbollah has been wounded but not defeated,” said Dr Ghoncheh Tazmini, author of Power Couple: Russian-Iranian Alignment in the Middle East (2023), in a TNA interview.

“History has shown that the elimination of such leaders does not eradicate the groups they belong to. These organisations have adapted, evolved, and continued their missions even after losing their most prominent figures,” she added.

“Targeted assassinations may create temporary disruptions, but organisations like Hamas, Hezbollah, and the [Islamic Revolutionary Guard Corps (IRGC)] are structured for continuity. They have developed deep, multi-layered leadership hierarchies and ideologies that are designed to outlast individual leaders. As we have seen, when a key figure is killed, another is swiftly elevated to replace them, ensuring the organisation remains functional and operational.”

Examples worth considering are the killings of Hamas’ Ismail Haniyeh earlier this year, Soleimani in 2020, and Hezbollah’s Abbas al-Musawi and Ragheb Harb in 1992 and 1984, respectively. Since the US assassinated Soleimani almost five years ago, Esmail Qaani quickly assumed leadership and the IRGC has maintained its regional influence even with a different command-and-control structure.

Similarly, when Hamas and Hezbollah’s previous leaders were killed by the Israelis, these resistance organisations demonstrated their means to regenerate leadership, highlighting their “resilience”, “institutional depth”, and ability to “survive external pressure” over decades, according to Dr Tazmini.

She noted how the IRGC and Iran-backed armed groups in Arab countries/territories use “sophisticated methods to preserve their infrastructure, even under relentless pressure” which have been achieved through “leveraging local support, regional alliances, and their own resources” in ways that enable them to “rebuild or bypass systems” that are damaged or targeted.

“Moreover, attacking communications networks or infrastructure doesn't guarantee the neutralisation of a group's operational capabilities. The pager/walkie-talkie attack - has that really destroyed Hezbollah's communication network? In 2008, the Lebanese government attempted to dismantle Hezbollah’s vast wire communications network,” observed Dr Tazmini.

“The decision sparked violent protests and revealed the depth of Hezbollah’s integration into Lebanon’s political and social fabric. Not only did the government fail to dismantle the network, but Hezbollah quickly adapted and maintained its communication capabilities.”

Guerrilla warfare in southern Lebanon

The Israeli military has been building up its troop presence along the Lebanese border. According to some sources, it has already commenced “small operations” in southern Lebanon.

If Israel goes ahead with a ground invasion of southern Lebanon, Hezbollah could find itself with many advantages over the Israelis. Mindful of the fact that Hezbollah, which is of course a Lebanese group, knows the Lebanese terrain extremely well and has spent many years preparing for another Israeli ground invasion, such a scenario would present Hezbollah with opportunities to fight Israeli occupiers on their own soil.

This potential situation could enable Hezbollah to regrow and regain morale following Nasrallah’s killing and other blows it has taken from Tel Aviv this year.

“It is going to take Iran years to rebuild the potency of its network, and in particular its flagship militia, Hezbollah. However, Israel might make the task quicker and easier by occupying a swath of southern Lebanon and declaring it a ‘security buffer zone,’ which would provide Hezbollah with a guerrilla battleground in which to focus its rebuilding efforts,” Dr Ibish told TNA.

Iran's path forward

A major concern for policymakers in Tehran is that Israel might be planning for a direct attack on Iran after assessing that Hezbollah is weakened to the point whereby the Lebanese group ceases to deter Tel Aviv from taking such direct military action against the Iranian homeland.

If the Israelis do wage such strikes against Iran and its nuclear facilities, there would be significant repercussions inside the Islamic Republic in terms of the Iranian population’s perceptions of their government’s ability to secure the country from external threats and preserve Iran’s vital national interests.

“Such massive strategic failures have initiated a slow but steady process towards regime change in other authoritarian states, and even though there is no sign of this in Iran now, the leadership of the Islamic Republic must be nervous about the possibility that Iranians may conclude that this leadership is incompetent, reckless, and simply too unsuccessful to retain confidence and remain in control of Iranian national interests,” noted Dr Ibish.

Despite what Israel may do next, Iran’s leadership will probably not consider walking away from its foreign policy doctrines in the Middle East.

“At this juncture, Iran must weigh what serves its national interests, and a full-fledged regional war may not align with the new president’s more moderate political platform. However, support for the resistance is a different matter,” explained Dr Tazmini.

The analyst said that Iran will continue to express solidarity and provide political and military support to Hezbollah, sticking to its defence doctrine of strategic depth, a forward defence model, and the projection of soft power.

“Hezbollah will regroup with Iran’s assistance seeing as it is a vital nodal point, if not crown jewel, on Iran’s Axis of Resistance,” she told TNA.

Analysts such as Ali-Khan assess that the less risk-averse members of the ‘Axis of Resistance’ such as Yemen’s Houthis will intensify their attacks on Israel in light of Nasrallah’s assassination and the recent intensification of Israeli airstrikes on Lebanon.

Notably, on 28 September the Houthis launched a ballistic missile at the Ben Gurion airport, which the Israelis claim to have intercepted. The next day, Israel responded by bombing Hodeidah. Mohammed Abdulsalam, an Ansar Allah spokesperson for the Houthis, took to social media to declare that Israel’s 29 September strikes on the Red Sea port city would not cause Ansar Allah to “abandon Gaza and Lebanon”.

Looking ahead, Yemen’s de facto Sanaa government may intensify its maritime attacks in the Gulf of Aden and Red Sea as part of its response to Israel’s killing of the Hezbollah leader.

If the Lebanese organisation’s influence within the ‘Axis of Resistance’ wanes, there is good reason to assume that Ansar Allah will step up its role among Tehran’s network of allies, presenting itself to the Islamic Republic as an increasingly valuable actor worthy of greater levels of Iranian support in various forms. Whether or not the Iranians pass advanced Russian weaponry along to the Houthis will be important to consider.

The nuclear option

Nearly one year into Israel’s war on Gaza, the Middle East has changed dramatically, prompting Tehran to carefully navigate developments on the ground in Israel, Palestine, Lebanon, Yemen, and elsewhere in the region.

When addressing the future of Iran’s foreign policy in the Middle East following Nasrallah’s killing, there are many unknown variables in the equation. But it seems obvious that the chances of Iran deciding to develop a nuclear weapon have significantly increased this month.

The Islamic Republic’s leadership might see an acceleration of Tehran’s nuclear program as a solid deterrent, which could potentially ease the burden on Iran’s non-state actor allies in the region, chiefly Hezbollah.

“The most logical Iranian conclusion from the debacle of the past couple of months in Lebanon is that the ‘axis’ forward defence strategy is largely a failure and that the most important task for the Islamic Republic is to move as quickly as possible, without taking undue risks, towards nuclear weapon status as the only real deterrent against Israel and key to regime survival,” holds Dr Ibish.

Tehran has spent the past year trying to avoid a direct war with Tel Aviv. However, in that process, Iran’s options have become “fewer, weaker, and more dangerous,” Dr Parsi told TNA. “Whatever move it makes, it risks sparking the regional war it has sought to avoid. The more cornered Iran gets, the stronger the voices will become for Tehran to go nuclear.”

Ultimately, although the likelihood of Iran doubling down on its nuclear program has recently increased, there is no guarantee that this nuclear strategy would be smooth or problem-free for Tehran.

As Ali-Khan explained, “This path is fraught with risks, as it would likely provoke a stronger, more urgent Israeli response - something Iran wants to avoid.”

Giorgio Cafiero is the CEO of Gulf State Analytics.

Follow him on Twitter: @GiorgioCafiero