A Second Front in Hamas’s War?

All intelligence agencies fail, often spectacularly. The Central Intelligence Agency’s faulty assessments of Saddam Hussein’s nuclear program before the Iraq war, the German intelligence service’s conviction that Russian President Vladimir Putin was bluffing about invading Ukraine, all three Russian intelligence services’ certainty that Ukrainian forces would quickly fold—failure is the price of admission in a profession that must anticipate what a foreign actor will do based on information that is hidden, incomplete, flawed, and sometimes deceptive. 

For Israel’s intelligence services—among the best trained, most dedicated, and technologically advanced in the world—the events of October 7 are an especially painful failure. The months and years to follow will allow for a thorough examination of how a world-class intelligence apparatus, with vast and precision intelligence collection focused on the Gaza Strip and its Hamas leadership, could have missed indications of such a major attack. Believing the threat from Hamas was predictable and contained, Israel likely devoted its best technical and human intelligence capabilities to seemingly more significant threats from Iran and Hezbollah. Not all intelligence assets are created equal, and what was left covering the Gaza Strip may have been insufficient in scope and subpar in capability.  

Yet often neglected in intelligence post mortems is the role of the target itself. Failure results not just from internal flaws; it can also be induced by an adversary adept at denial and deception and willing to use previously hard-to-imagine tactics. To conceal an attack of this scale and complexity and achieve complete tactical surprise amid ample warning indicates a dramatic increase in Hamas’s intelligence and security capabilities in recent years. Such capabilities have been the hallmark of another militia, one with which Hamas, not coincidentally, has recently mended ties: Hezbollah. Whether by observing and applying the tactics the Lebanese group has learned over four decades of intelligence warfare with Israel or by, as appears likely, receiving direct training, advising, and planning in Beirut, Hamas in its attack displayed an audacity, savagery, and sophistication that Israeli and Western intelligence services would have thought possible only from Hezbollah.  

As Israel fights to regain control of its villages and citizens, it is also preparing for something it has sought to avoid since withdrawing from the Gaza Strip in 2005: a ground invasion and an all-out war with Hamas on its home turf. But with war afoot in the south, another question looms to the north: what will Hezbollah do? The Lebanese group has sat out previous rounds of conflict between Israel and Hamas. But Israeli and U.S. policymakers should not overlook the risk that a protracted war would cause Hezbollah to change its calculus—precipitating an even more devastating conflict that could quickly escalate into a regional war. Even as Israel focuses its forces on the Gaza Strip, it and its allies must simultaneously reestablish a deterrent to the north, to ensure that Hezbollah continues to stay on the sidelines.

“OUR HEARTS ARE WITH YOU” 

Both Hamas and Hezbollah have long benefited from Iranian support. While nurturing Hezbollah’s rise in Lebanon the 1980s and 1990s, Tehran also looked for opportunity in the Palestinian territories, at a time when Hamas was emerging from the First Intifada. While Hezbollah is Shiite (like the Iranian regime) and Hamas is Sunni, both displayed ferocity, Islamic fundamentalism, and dedication to Israel’s destruction—all of which suited Tehran’s strategy of building regional proxies. So began two decades of Iranian military, political, and financial support to both groups. 

In the 1990s and the decade after, Hezbollah and Hamas themselves forged close ties, as mutually supporting fronts in Iran’s “axis of resistance.” Hezbollah hosted Hamas leadership in Beirut; trained with Hamas fighters camps in southern Lebanon and in the Bekaa Valley in eastern Lebanon; and smuggled weapons and materiel to the Gaza Strip during the Second Intifada (from 2000 to 2005). By the start of the 2010s, the two militias were close partners. 

Those bonds were strained starting in 2011, as the Syrian uprising erupted into civil war: Hamas chose the side of the Sunni street against the Hezbollah- and Iran-backed regime of Syrian leader Bashar al-Assad, another member of Tehran’s axis of resistance. But the alliance recovered as the Syrian civil war began to wind down, especially once Yahya al-Sinwar—a long-time collaborator with both Tehran and Hezbollah—took over the leadership of Hamas in 2017. Since then, the partnership has solidified, with Lebanon becoming a critical hub for coordination. In 2018, Hamas reopened its political offices in Beirut, and several key leaders relocated there. In 2021, Iran reportedly established a “joint operations room” there, staffed with operatives from Iran’s Islamic Revolutionary Guard Corps, Hezbollah, and Hamas to coordinate military, intelligence, and terrorist activities against Israel.  

Hezbollah may have already changed its assessment of Israeli capabilities.

Hamas has had much to gain from this partnership. Hezbollah fighters have acquired considerable military experience by joining wars in Iraq, Syria, and Yemen, as well as from the group’s own long-running shadow war with Israeli intelligence services. Particularly valuable to Hamas has been Hezbollah’s expertise in intelligence, counterintelligence, operational security, and deception. It seems likely that key aspects of Hamas’s attack on Israel were shaped in that Beirut operations room under Hezbollah’s tutelage.  

Despite offering training and support to Hamas, Hezbollah may not want to directly intervene in the war with Israel that started with last weekend’s attack. The day after, Hezbollah’s number two official, Hashim Safi al Din, made a promise: “Our hearts are with you. Our minds are with you. Our souls are with you. Our history and guns and our rockets are with you.” Conspicuously missing from this pledge was any indication that Hezbollah’s soldiers were with Hamas. In other recent clashes between Israel and Hamas (in 2008, 2014, and 2021), Hezbollah has offered political support and conducted the occasional cross-border attack to demonstrate resolve but otherwise stayed on the sidelines. It has several good reasons to do the same now.  

First, Hezbollah is still recovering from a decade of fighting in regional wars in support of Iran. Those efforts cost the group thousands of lives, millions of dollars, and considerable stockpiles of weapons and materiel. Even now, it is straining under the burden of ongoing costs of caring for the wounded and compensating the families of “martyrs.” What’s more, at a time when Lebanon is particularly paralyzed and divided and when much of the political establishment resents Hezbollah for its role in blocking the election of a president and the formation of a new government, the group’s leader, Hassan Nasrallah, will be keen to avoid further antagonizing other political factions and embroiling Lebanon in a war most of its citizens want to avoid. And Nasrallah will want to avoiding expending manpower and missiles on a fight that is not, for Hezbollah, existential; ultimately, its military forces and advanced weapons exist to secure power in Lebanon, to deter Israel, and to employ in service of Tehran in the event of an Israeli-Iranian war.  

Hezbollah’s early actions reflect a desire for restraint. On Sunday, it exchanged artillery and rocket fire with Israeli forces in the contested border region of Shebaa Farms; on Monday, Israeli airstrikes, in response to a cross-border raid by Palestinian militants, killed Hezbollah fighters. In response, Hezbollah chose to shell Israeli military installations rather than escalate with targeted attacks on Israeli personnel or civilians, suggesting that it saw Israel’s actions as in keeping with the rules of the game of proportional response. 

“WEAK AS A SPIDER’S WEB”

Yet initial restraint should not be cause for complacency. For one thing, such tit-for-tat exchanges leave ample room for miscalculation and misperception, particularly at a time of heightened tensions, and what one side sees as a proportional response the other might consider a drastic escalation. Miscalculations triggered a large-scale war in 2006, after a Hezbollah raid into Israel and abduction of Israeli soldiers provoked an all-out Israeli invasion. Nasrallah later conceded that he had not anticipated such a reaction. 

Miscalculation is not the only risk. If fighting between Israel and Hamas continues to escalate, Hezbollah, sensing weakness, could be tempted to abandon its caution and intervene. That will be particularly likely if Israel, its leaders seeing no choice but to launch an all-out assault into the Gaza Strip to deal a devastating blow to Hamas and rescue Israeli hostages, ends up bogged down in urban warfare. As its forces are pummeled and casualties in the strip mount, Hamas will have every reason to call for help from its partners—putting pressure on Hezbollah to enhance its support. 

Hezbollah’s leaders may see a once-in-a-generation opportunity to strike directly into northern Israel.

Hezbollah, meanwhile, may have already changed its assessment of Israeli capabilities. Following its withdrawal from southern Lebanon in 2000, Nasrallah called Israel “weaker than a spider’s web”—menacing from a distance but vulnerable when challenged. Although the ensuing two decades did much to remind Hezbollah of Israel’s superior capabilities (and the destruction it could wreak on southern Lebanon), Israel’s military and intelligence failure in recent days has likely undercut that deterrent. With Israeli soldiers bogged down, Israeli intelligence distracted, and an ally under duress, Hezbollah’s leaders may see a once-in-a-generation opportunity to strike directly into northern Israel. Indeed, its entire military apparatus—infantry, special operators, and rocket, missile, and drone forces—is trained, oriented, and indoctrinated for this exact scenario. Nasrallah may step back and ask why Hezbollah has accumulated all of these capabilities to fight Israel if it is never going to use them.  

An attack would escalate quickly, with little to stop it from erupting into full-scale regional war. Hezbollah’s capabilities would allow it to attack by land, sea, and air, supported by artillery and rocket munitions. Precision missiles could target Israeli military and intelligence facilities and key infrastructure and even reach sensitive sites in Jerusalem and Tel Aviv. Israel, in turn, would unleash a devasting air campaign across Lebanon. Hezbollah’s backers—from Iran and Syria to Shiite militias in Iraq and perhaps as far away as Afghanistan and Pakistan—would be pressured join the fight. And before long, the United States could easily get dragged in, its forces and facilities facing attacks throughout the Middle East. Iran could respond by activating cells in the region and beyond. 

Such a dire scenario is avoidable. But preventing it will require enhancing deterrence along Israel’s border with Lebanon, where Hezbollah watches from the other side. The credibility of that deterrent will depend in part on Israel’s effectiveness in striking back against Hamas. But it will also require simultaneous efforts against Hezbollah, including signaling (for example, by moving key military units and strike weapons toward the northern border), shows of force (including naval deployments to Lebanon’s coast and regular combat aircraft and surveillance-drone patrols over Hezbollah strongholds), and attacks as needed on Hezbollah fighters encroaching on Israeli territory. The United States also has an important role to play. It can bolster Israeli efforts by deploying its own air and naval forces in the region and by communicating to Iran and Hezbollah that further escalation will lead to more crippling sanctions and, in the event of all-out conflict, U.S. strikes on the group. But for now, a strong deterrent should prevent the situation from coming to that.