It’s not often that Hezbollah finds common ground with U.S. leaders. But in February, Hassan Nasrallah, the Lebanese party and paramilitary group’s top official, made an exception. U.S. Secretary of State Mike Pompeo had warned that Hezbollah was growing “more powerful.” Nasrallah agreed, and for good reason. Fresh off victories on the battlefield in Syria, with a vast weapons arsenal in Lebanon, a political ally in power, and committed allies across the region, Hezbollah has more military and political power today than at any point since its founding in 1985.

Yet this new strength has brought with it new troubles. Hezbollah’s unchecked expansion in the Levant has not only brightened the U.S. spotlight on the group’s activities but set off alarm bells in Israel. Major Israeli military strikes inside Lebanon—a first since Israel went to war against Hezbollah in 2006—are now a distinct possibility.

Hezbollah, already balancing a number of domestic and regional obligations, is not keen on another major conflict. Yet the group is in a bind: with every step it takes to brace for a possible Israeli attack, such a confrontation becomes more likely. Hezbollah’s actions in the months ahead will show whether it can walk this thin line. Failure could spell disaster—for the group, for Lebanon, and for the region.


Hezbollah is just emerging from a years-long campaign of military adventurism in the region. In 2013, the group began sending thousands of fighters into Syria, where they defended the regime of Syrian President Bashar al-Assad regime against opposition forces as well as the Islamic State (ISIS), the al-Nusra Front, and other terrorist groups. Because Syria—the linchpin of the anti-Western, anti-Israel “axis of resistance” formed by Hezbollah, Iran, and Syria—acts as a thoroughfare for Iranian weapons for Hezbollah, the war was an existential matter for the group. In 2017, Hezbollah fighters helped the Assad regime retake Aleppo. Later, they pushed east toward the Iraq border and the Euphrates River valley, blocking the advance of U.S.-backed Kurdish and Arab forces. Moving southward from Damascus to the Golan Heights, they defeated remaining opposition forces and strengthened axis capabilities vis-à-vis Israel, building military facilities and weapons infrastructure.

Hezbollah is just emerging from a years-long campaign of military adventurism in the region.

The fight in Syria absorbed much of Hezbollah’s manpower, but smaller expeditionary missions fanned out to other hot spots. The group joined Iran in deploying trainers and advisers to support Shiite militias fighting ISIS in Iraq. In Yemen, Hezbollah and Iran came to the aid of the Houthi rebels in their fight against the country’s government and a military intervention led by Saudi Arabia and the United Arab Emirates. Hezbollah advisers remain in Yemen, building up Houthi military capabilities and pulling their Gulf adversaries deeper into the quagmire.

A relatively quiet domestic front has helped Hezbollah maintain its deployments abroad. From 2013 to 2015, a series of attacks by ISIS and the al-Nusra Front in Beirut and along Lebanon’s border with Syria threatened to destabilize the country, but Hezbollah and the Lebanese Armed Forces (LAF) successfully expelled the groups. On Lebanon’s southern border with Israel, tensions occasionally flared up between Hezbollah and the Israel Defense Forces (IDF), but the situation never escalated. All the while, Hezbollah gradually established itself as Lebanon’s main armed actor, unmatched by the LAF or rival militias.

A U.N. peacekeeper near a poster of Hezbollah leader Hassan Nasrallah in southern Lebanon, November 2017
Ali Hashisho/REUTERS

The group’s political star rose during the same period. For over a decade, Hezbollah had maintained an alliance with Lebanon’s largest Christian party, the Free Patriotic Movement (FPM). The party’s founder, Michel Aoun, assumed the presidency in 2016. With a sophisticated political and media apparatus, Hezbollah and its FPM-led alliance won decisively in national assembly elections last year, capturing an unprecedented number of assembly seats and cabinet ministries. 

Victorious on foreign battlefields and at the ballot box, Hezbollah has emerged from the region’s turmoil stronger than ever. Politically, the group now holds a de facto veto over state policy and can keep rivals such as Prime Minister Saad al-Hariri in check. Meanwhile, the war in Syria has transformed the group’s military from a defensive guerrilla force into a full-fledged army. With six years of experience across a spectrum of military landscapes—from urban warfare in Aleppo to mountain warfare along the Syria-Lebanon border and rural clearing operations in eastern Syria—Hezbollah’s 20,000 to 30,000 active-duty fighters arguably form the most battle-hardened and effective Arab army today. If it blends its defensive capabilities in southern Lebanon with the offensive capabilities it gained in Syria, the group could be capable of both repelling Israeli incursions and launching attacks into Israeli territory.

Victorious on foreign battlefields and at the ballot box, Hezbollah is stronger than ever.

Hezbollah has further evolved into a regional player to be reckoned with. Expeditionary war taught it how to deploy and sustain forces abroad. In the process, the group built an arc of allies stretching from Iran through Iraq and Syria to Lebanon. The result is not only military interoperability but ideological bonds between axis members who now understand themselves as brothers-in-arms against Israel, the United States, Saudi Arabia, and Gulf allies. Shiite allies, such as Houthis in Yemen and the Popular Mobilization Forces in Iraq, view Hezbollah leader Nasrallah as inspirational and his group’s maturation into a military, political, and socioeconomic heavyweight as a model to emulate.


Officials in Israel have watched Hezbollah’s transformation—especially its successes in Syria—with growing alarm. Hezbollah’s push into southwest Syria, in tandem with the paramilitary arm of Iran’s Islamic Revolutionary Guard Corps, the Quds Force, allowed it to build bases abutting the Golan Heights. With Iranian support, the group has cultivated Shiite militias from Afghanistan, Iraq, Pakistan, and Syria, all willing to join Hezbollah in a war with Israel. For Israeli officials, the coming confrontation would be not the “Lebanon War” but the first “Northern War,” spanning Lebanon and Syria.

Hezbollah could also bring the fight directly to Israel. Earlier this winter, the IDF carried out a six-week operation to destroy several Hezbollah tunnels stretching from southern Lebanon into northern Israel, but it conceded that more secret passages likely remained undetected. Gadi Eizenkot, then the outgoing IDF chief, described the tunnels as “Hezbollah’s Operation Barbarossa,” a reference to the Wehrmacht’s surprise invasion of the Soviet Union in 1941. 

Even more worrying, in Israel’s eyes, are Hezbollah’s efforts to domestically produce precision-guided munitions. The group already owns a formidable arsenal of drones, long-range rockets, and short-range surface-to-air and antiship missiles. Now Israeli officials believe that Hezbollah, with help from Iran, is converting “dumb” rockets into highly accurate missiles using small and hard-to-detect GPS guidance kits. Such precision weaponry, if produced on a mass scale, could erode Israel’s technological advantage in air defense and enable Hezbollah to hit Israeli military and civilian targets with pinpoint accuracy.

Israeli leaders, watching these changes unfold, may decide that the costs of inaction are too high. Ever since its 2006 war against Hezbollah, Israel has avoided major strikes inside Lebanon for fear of unwanted escalation with uncertain consequences. Instead, it has carried out air strikes against Hezbollah and Iranian targets inside Syria, repeatedly hitting convoys and weapon depots. Now Israel might conclude that only direct strikes against Hezbollah’s home base will contain the group. Some statements by senior Israeli military officials already seem to point in this direction.


How would Hezbollah respond to an Israeli operation against, say, its rocket-to-missile conversion sites? On the one hand, the group is already spread rather thin. Its rise has come at a heavy cost in blood and treasure. Hezbollah suffered thousands of casualties in Syria and was left with the financial burdens of caring for the wounded and the families of “martyrs.” Meanwhile, the risk of a resurgent ISIS means Hezbollah must keep troops in Syria and Iraq that it had hoped to withdraw. None of this makes war with Israel an appealing prospect.

On the other hand, the group’s leaders could hardly afford to tolerate an Israeli strike in Lebanese territory without some kind of retaliation—especially given Hezbollah’s role as vanguard of the anti-Israel coalition. Yet the very steps necessary to deter Israel from taking significant action and ensure the group can retaliate if Israel does strike may provoke Israel and thus make war more likely—a classic case of the security dilemma.

Consider the issue of military equipment: advanced weapons are Hezbollah’s only chance against Israel’s high-tech military and formidable defenses, but those acquisition efforts are precisely what could trigger Israeli action. Nonetheless, Nasrallah will likely conclude that Hezbollah must continue building an ever more sophisticated and voluminous arsenal to counter Israel.  

Fire rises from Beirut International Airport after Israeli airstrikes in July 2006
Mohamed Azakir/REUTERS

If Israel were to strike, Hezbollah would face another conundrum: how to deliver a response forceful enough to deter further Israeli action but not so destructive as to invite further escalation. The informal “rules of the game” developed over the past decade suggest that Hezbollah might respond proportionally with an attack on an Israeli military facility with few or no casualties. Yet these tit-for-tat exchanges leave ample room for miscalculation and misperception, and what one side sees as a proportional response, the other might consider a drastic escalation. In 2006, it was a deadly Hezbollah raid on IDF soldiers that provoked Israel to go to war—a reaction that, Nasrallah later conceded, he in no way anticipated. Thus, conflict could quickly escalate even if neither side wants an all-out war.

Conflict could quickly escalate even if neither side wants an all-out war.

Nasrallah likely knows that in such a war with Israel, Hezbollah could at best fight the IDF to a draw. Such a stalemate would entail immense destruction—to the group, its Shiite base, and swaths of Lebanon. Moreover, what begins as a limited conflict could descend into regional war: Israeli strikes on Hezbollah in Syria, for instance, could ensnare the Assad regime, Iran, or Russia. Likewise, Hezbollah rocket barrages against the IDF, Israeli leadership, or civilian communities could trigger calls for U.S. intervention.


A crisis can still be averted. In all likelihood, Nasrallah understands that a destructive, protracted war would jeopardize everything Hezbollah has achieved at home and in the region. But this awareness alone is not enough. The international community needs to press Hezbollah to curtail its most provocative activities, such as its production of precision munitions and construction of cross-border tunnels. UN forces in Lebanon can facilitate dialogue between Israeli and Lebanese officials to calm heated tempers. Countries with ties to both sides, such as Russia, could do their part to lower the risk of unwanted escalation by serving as conduits for back-channel communication.

For now, the mutual understanding that the 2006 war would pale in comparison with the destruction a new conflict would wreak has kept both sides from direct war. But there is no guarantee that this détente will last. In the end, Hezbollah’s recent victories may be its undoing.

You are reading a free article.

Subscribe to Foreign Affairs to get unlimited access.

  • Paywall-free reading of new articles and a century of archives
  • Unlock access to iOS/Android apps to save editions for offline reading
  • Six issues a year in print, online, and audio editions
Subscribe Now
  • BRIAN KATZ is Visiting Fellow in the International Security Program at the Center for Strategic and International Affairs Fellow at the Council on Foreign Relations. He served as Country Director for Syria in the Office of the Secretary of Defense (OSD) and as a military analyst for the U.S. Intelligence Communities, focused on the Middle East and counterterrorism. The author is an employee of the United States government currently on leave from his employment. All statements of fact, opinion, or analysis in this work are those of the author and do not reflect an official position or views of the United States government.
  • More By Brian Katz