Hizballah's response to military action against Iran could be shaped by rational cost-benefit analysis, a perceived spiritual obligation to defend its Shiite patron in Tehran, or both.
The potential consequences of an American or Israeli preemptive strike against Iranian nuclear weapons sites are legion. For example, Tehran might fire missiles in retaliation, launch terrorist attacks, or attempt to disrupt oil flows through the Persian Gulf. Until recently, conventional wisdom also held that the Iranian-backed Lebanese Shiite militia Hizballah would unleash its rockets on Israel in response to such an attack on Iran. Yet despite continued claims by senior Hizballah officials that an assault on the Islamic Republic "means the whole region will be set alight," other statements by Hassan Nasrallah, the organization's secretary-general, have raised doubts about whether the militia would in fact respond.
Hizballah was established in Lebanon in the early 1980s with Iranian political and financial support. During the 1982 Israeli invasion, Tehran dispatched 1,500 Revolutionary Guards to the Beqa Valley to help organize a resistance force.
Today, unlike the majority of Lebanon's historically Iraq-oriented Shiite population, Hizballah members are required to embrace the doctrine of velayat-e faqih, which puts an Iranian mullah at the pinnacle of Shiite theology and politics. Critics point to this, along with the organization's professed goal in the early 1980s of transforming Lebanon into an Islamic state, as evidence that Hizballah is an agent of Iran.
Many in Israel and among Lebanon's pro-Western, anti-Syrian "March 14 coalition" believe that Hizballah takes strategic guidance, if not direct orders, from Tehran. Traditionally, Hizballah officials have not discussed the chain-of-command issue. In early February, however, after Iranian Supreme Leader Ali Khamenei broke a longstanding taboo and spoke openly about his regime's support for Hizballah, Nasrallah commented on the organization's relationship with Tehran. In discussing whether Hizballah would attack Israel in response to a strike on Iranian nuclear facilities, he said that Tehran had not made such a request and "would not ask anything of Hizballah." And if Khamenei were to ask, he said, Hizballah leaders would "sit down, think, and decide what to do."
Nasrallah's statement seems to suggest that calmer heads could prevail following an attack on Iran. As one article in the Hizballah-friendly Lebanese daily al-Safir noted last week, however, the key question is not what Iran asks of the organization, but what the group's "duty" is as "resisters in this battle." The answer is that Hizballah's spiritual obligations to Iran and the Supreme Leader are enormous. As Nasrallah deputy Naim Qassam once wrote, "The ultimate command in this Islamic path emanates from the Jurist-Theologian," that is, Khamenei. In deciding how to respond to a strike against its Iranian patrons, however, the militia would consider factors beyond the spiritual realm.
Over the past three decades, Hizballah has acquired significant material assets in Lebanon, including a massive arsenal and miles of sophisticated underground tunnel and bunker systems. These assets could be depleted or destroyed if the group opened a new conflict with Israel. In its thirty-four-day war against Israel in 2006 -- which the group sparked in July by launching a cross-border kidnapping operation -- Hizballah used and lost much of its arsenal and infrastructure, requiring years of rebuilding.
Although the militia clearly took pride in its 2006 performance, famously describing it as a "divine victory," Nasrallah also expressed regret at the escalation. "If I had known...that the operation would lead to such a war," he said in August of that year, "would I do it? I say no, absolutely not." Such sentiments reflect the significant downsides associated with this "victory." The war was extremely costly -- physical damage to Lebanon alone exceeded $6 billion, with Shiite areas being hit the hardest. And in addition to providing no strategic gain to Hizballah, the fighting ended with much of the organization's stocks exhausted, along with its tunnel systems destroyed and marginally more difficult to rebuild given the augmented presence of UN troops per Security Council Resolution 1701.
With Iranian and Syrian support, Hizballah rebuilt and retrenched, and the group now holds unprecedented quantities of even more advanced equipment that could carry it through several more rounds with Israel. Yet it is also aware that rearming in the future could prove challenging, particularly if Bashar al-Assad's embattled regime in Syria is toppled. The nominally secular Alawite regime in Damascus has been a strategic ally of theocratic Iran for more than thirty years, but if it should fall, it would undoubtedly be replaced by a Sunni regime that is unfriendly to the Shiite leadership in Tehran and Hizballah. Losing Damascus as a supplier and leading transshipment hub for Iranian weapons would likely compel Hizballah to rearm by sea, a more time-consuming and risky endeavor. Further complicating matters, Assad's fall could reinvigorate implementation of Resolution 1701's maritime interdiction component.
For years, Hizballah carefully cultivated its image as the defender of Lebanon and the leader of regional "resistance" against Israel. After the 2006 war, Nasrallah -- a Shiite -- became the most popular leader in the largely Sunni Arab world. Since then, however, a series of miscues has undermined the group's image in the region.
First came the 2008 armed takeover of Beirut in which Hizballah turned its weapons on the Lebanese people. Then the organization was implicated in the 2005 murder of former Lebanese premier Rafiq Hariri, the leader of the country's Sunni community. More recently, Nasrallah's frequent and impassioned apologia on behalf of the atrocity-perpetrating Assad regime have gutted what remained of the organization's popularity abroad.
Although there is little Hizballah can do about its diminished stature in the region, the militia requires continued support at home. Notwithstanding Nasrallah's oft-quoted claim that "we are going to win because [the Israelis] love life and we love death," most of his constituents do not want to die. Consider the aftermath of Hizballah military chief Imad Mughniyah's 2008 assassination in Damascus. Days afterward, Nasrallah made a fiery speech in which he threatened to attack Israelis at home and abroad. Subsequently, war-weary and nervous Shiites in southern Lebanon stopped rebuilding homes damaged by the 2006 war and flocked to the passport office in Tyre in preparation for another mass exodus.
Most Lebanese also realize that the next tangle with Israel will be even more costly than the previous one. Both sides have had ample time to plan and prepare, and Israel has repeatedly pledged to institute its "Dahiya Doctrine" in any future conflict, targeting not only Hizballah assets, but also the entirety of Lebanese civilian infrastructure. While few Lebanese would concede that Israel's 2006 operations were restrained, any future war promises to be much more destructive. Should Hizballah -- an organization desperately trying to assert its Lebanese identity -- retaliate, it will risk being held responsible for initiating another war with Israel on Iran's behalf.
It is difficult to assess how Hizballah will weigh each of these factors in its decisionmaking. Tehran no doubt hopes that the threat posed by the militia will deter an Israeli or American attack, but once such a strike has been undertaken, the value of covering Israel with missiles would be more symbolic than strategic. According to former Mossad chief Meir Dagan, Hizballah retaliation would have a "devastating impact" on daily life throughout Israel, but the assured physical devastation of Lebanon could convince both Tehran and Hizballah that the cost to the militia's capabilities and local standing is too high.
Despite the potential aftermath of retaliation, Hizballah could nevertheless find itself unable to remain completely on the sidelines. Instead of going all in, the militia might attempt to calibrate its response to elicit a more proportional Israeli reprisal. For example, rather than targeting the Israeli Defense Ministry in Tel Aviv with longer-range missiles, it could rain Katyushas on the north and dare Israel to escalate. After miscalculating in 2006, Nasrallah may or may not wish to test the tides again. In any event, Israel could help avoid this dynamic by publicly signaling the consequences of any Hizballah reprisal.
With Assad on the ropes, Hizballah faces unprecedented constraints and pressures that will only increase if he is toppled. From a strict cost-benefit perspective, then, the militia could determine that attacking Israel in response to a strike on Iran would be counterproductive. In the end, however, the decision might be predicated not on rationality, but on the higher authority of Hizballah's perceived obligation to defend its chief religious authority in Tehran.
David Schenker is the Aufzien fellow and director of the Program on Arab Politics at The Washington Institute.