The recapture by pro-Assad regime forces—including Lebanese Hizballah—of rebel-held Aleppo (December 2016) and of IS-held Deir al-Zur (ongoing as of September 2017) may not just mark the denouement of Syria’s tragic civil conflict, but may also pave the way for the next Hizballah-Israel war. Buoyed by these successes, Hizballah leaders have increased the frequency and volume of their war talk. Thus, in February, Hizballah Secretary General Hassan Nasrallah warned (as he has in the past) that there would be “no red lines” in a future war with Israel. In April, Hizballah held a press conference along the border to highlight Israeli defensive preparations and to declare its readiness for war. And in June, Nasrallah pledged that Hizballah would be joined in a future war by “tens…or even hundreds of thousands” of Shi‘a fighters from Iraq, Iran, Yemen, Afghanistan, and Pakistan.

These statements and activities were likely motivated by Hizballah’s desire to restore its image as a “resistance” organization whose principal raison d’etre is fighting Israel, which has been tarnished by its role in fighting Arab-Muslim rebels in Syria. Had Israel wanted to attack Hizballah, any time during the past six years would have been better than now, with the Syrian war winding down. So it is unlikely that these statements were prompted by a change in Hizballah’s assessment of the threat posed by Israel. Israel has responded to Hizballah’s operations in Syria and to what it sees as growing Hizballah military capabilities with its own talk and actions. In September 2017 it held what was billed as the largest military exercise in decades in a rehearsal of a war with Hizballah. The rhetoric and actions on both sides have focused renewed attention on the possibility of another Hizballah-Israel war.

It may seem unlikely that Hizballah would start such a war while thousands of its fighters remain dispersed throughout Syria, but it should be recalled that its last war with Israel in 2006 as well as Hamas-Israel conflicts in Gaza in 2008–09, 2012, and 2014 were the unintended outcomes of miscalculations by both parties. So the possibility of war, at least in the near-term, cannot be dismissed. In the long run, however, another Hizballah-Israel war seems likely, as the “axis of resistance” (whose core members are Hizballah, Iran, and Syria)—emboldened by their apparent success in Syria and perhaps by the Russian military presence there—may be tempted to provoke Israel. However such a conflict starts, one thing is clear: The next Hizballah-Israel war will likely be the most destructive Arab-Israeli war yet.

“Resistance” and Hizballah’s “Forever War” with Israel

Nasrallah has generally shown himself to be a careful, prudent decision-maker, despite his frequent resort to provocative rhetoric. Yet the potential for miscalculation and escalation is inherent in Hizballah’s doctrine of “resistance” (muqawama), which shapes its approach to Israel. The concept of resistance was adopted as a slogan by the Palestinians in the 1960s, fashioned into a quasi-religious doctrine of armed struggle by Hizballah during the Israeli occupation of southern Lebanon in the 1980s, and subsequently appropriated by Iran and Syria. The concept resonates with many Lebanese Shi‘a, with its evocation of the “resistance” and martyrdom of the Shi‘a Imam Hussein at Karbala in 680 CE at the hands of the Caliph Yazid’s army. Even though the Israeli withdrawal from Lebanon in 2000 was ratified by the UN, Hizballah claims that Israel continues to occupy Lebanese territory (Sheba Farms in the Golan and the ruins of seven Shi‘a villages in northern Israel), providing a pretext for continuing its armed struggle against Israel.

The resistance doctrine exhorts its adherents to stand fast in the face of threats, to push boundaries, and to eschew compromise on matters of principle. It posits that victory is achieved by imposing costs and by demoralizing the enemy—by relentless psychological warfare, terrorizing and bleeding the enemy’s population and military, and denying it battlefield victories. The purported success of various arms of the “Islamic resistance” in pushing Israeli forces out of Lebanon (2000) and Gaza (2005) and U.S. forces out of Iraq (2011), and in thwarting alleged U.S., Saudi, and Israeli conspiracies to overthrow the Assad regime in Syria (since 2011) has convinced its adherents that they have hit on a formula for defeating their enemies.

For Hizballah, resistance is a way: to forge a proud, confident Shi‘a identity; to build resilience by inculcating a culture of “resistance, jihad, and martyrdom;” and to advance its goal of destroying the Jewish state. Israel is portrayed in Hizballah propaganda as a fragile, artificial entity whose continued existence is, as Nasrallah famously claimed in a speech following its May 2000 withdrawal from Lebanon, as tenuous as “a spider’s web.” These premises raise the possibility that Hizballah might overreach or miscalculate in the future, as it has done in the past. Indeed, the resistance doctrine has propelled Hizballah and the Palestinian Hamas (an occasional member of the “axis of resistance”) into several destructive conflicts with Israel in Lebanon and Gaza that have imposed heavy tolls on their societies. Israel, however, has proven more resilient than anticipated. Indeed, a propensity to overreach seems to be woven into the DNA of “axis of resistance” members.

Since its withdrawal from Lebanon, Israel’s main preoccupation has been ensuring quiet on its northern frontier, by deterring Hizballah activities against Israeli military personnel and civilian residents. The standoff with Hizballah, however, has implications that go far beyond the security of Israel’s northern border. Hizballah’s past military successes against it, amplified by a prodigious propaganda machine, have undermined Israel’s deterrence image, emboldened some of its most implacable enemies (such as Hamas), popularized the resistance “brand” in the Arab world (at least prior to Hizballah’s intervention in Syria), and served as a model and inspiration for radical Shi‘a throughout the region. Hizballah, moreover, is Iran’s main proxy in its long war with Israel. Iranian leaders frequently proclaim that “Israel should be wiped off the map” and have facilitated Hizballah military operations and terrorism against Israel and Jewish targets. Hizballah’s massive rocket/missile arsenal (larger than that of most states) is part of Iran’s strategic deterrent, and would probably be used for retaliation in the event of an Israeli strike against Iran’s nuclear infrastructure.

From War to War

For these reasons, both Hizballah and Israel have prepared intensively for the next round of fighting. In recent years, Hizballah has expanded greatly the size and range of its rocket/missile inventory (in violation of UN Security Council Resolution 1701, which defined the terms of the cease fire ending the last round of fighting, and which prohibits arms transfers to Hizballah). It has enhanced its antiarmor capabilities with additional antitank weapons, and improved its air and coastal defense capabilities with modern systems acquired from or through Syria. It has improved its defensive dispositions in southern Lebanon, deeply embedding its forces in towns and villages throughout the region. In addition, the group claims to have developed a capability to undertake offensive ground operations into northern Israel. Indeed, Nasrallah has threatened to do so in a future war, and its offensive military operations in Syria have given it the experience and capabilities to do so.

Hizballah’s strategic situation has changed as a result of its commitment, starting in 2012, of significant forces to Syria, where 6,000-8,000 personnel (out of perhaps 25,000) serve at any given time. On the one hand, this has reduced Hizballah’s readiness for a conflict with Israel. On the other hand, Hizballah has kept many of its anti-tank teams and rocket/missile crews in Lebanon—as these are crucial for any war with Israel—and it has gained operational experience in Syria that could make it more effective in a ground war. Moreover, in a future war, Hizballah might open a second front against Israel on Syria’s Golan—an option it did not have in the past.

Israel’s military has also greatly improved its capabilities since 2006. Israel now has a multilayered defense against Hizballah’s short-, medium-, and long-range rocket/missile threats, and its civil defense system has been tested and upgraded as a result of the 2006 Lebanon war and conflicts with Hamas. No defense is “airtight,” however, and Israel will also have to rely on offensive air and ground operations to deal with the Hizballah rocket/missile threat. Israel has also dramatically increased its ability to locate and hit targets by improving its intelligence, air, and artillery capabilities. It has enhanced its ground maneuver capabilities by deploying more advanced and capable tanks and infantry fighting vehicles (the Merkava IV and Namer, respectively) and by equipping key armored units with active defenses, to counter anti-tank weapons. Since 2006, Israeli training has emphasized operations against hybrid opponents like Hizballah, and major conflicts with Hamas in 2008–09 and 2014 resulted in improvements to equipment, training, and doctrine.

Lessons from Syria

Hizballah has undoubtedly gained experience and learned important lessons from its involvement in Syria’s civil war. Since 2012, Hizballah has sent advisors and fighters to Syria where they have fought against rebel forces with Syrian, Iranian, and Russian troops, and Shi‘a militiamen from Iraq, Afghanistan, and Pakistan. Hizballah fighters rotate through on deployments lasting from several weeks to several months duration. The experience of participating in sustained combat will build confidence, and improve the ability of Hizballah’s fighters to shoot, move, and communicate under fire. Moreover, their involvement in the planning and execution of complex, combined arms operations alongside Russian troops has undoubtedly taught them many important lessons regarding the employment of advanced weapons and tactics—including armor, fire support, unmanned aerial vehicles for ISR and attack missions, electronic warfare, and special forces.

On the other hand, as the U.S. military discovered after more than a decade in Afghanistan and Iraq, prolonged combat deployments often produce a decline in readiness for the full range of mission sets that units must prepare for. Hizballah is unlikely to escape this paradox as well. Moreover, Hizballah is engaged in combat in Syria against lightly armed irregular ground forces, which is not the kind of fighting it would engage in with Israel—an advanced military power that wages combined arms combat on the sea, air, land, and in the cyber domain. Thus, combat in Syria, while providing invaluable experience, will not prepare it for the full range of challenges it could face in a war with Israel—just as five years of fighting the second Palestinian intifada did not prepare the Israeli military for the 2006 war against Hizballah. Finally, reports that recent Hizballah recruits are less ideologically committed than previous generations of fighters and are often joining because they could not otherwise find work raise questions about the motivation and morale of Hizballah fighters. It likewise raises the possibility that Israeli intelligence may have many more collection opportunities than in the past. These factors could have an important impact on the conduct of a future war.

Political and Military Objectives

Recognizing that Hizballah cannot be destroyed by military means, Israel would nonetheless try to impose as much damage as possible on Hizballah as a military organization and on the infrastructure that facilitates its military operations—including the infrastructure of the Lebanese state. The principle goal would be to ensure the maximum period of quiet following a war, though Israel might also hope to further sully Hizballah’s image as Lebanon’s defender, and to engender a domestic political backlash against it. Israel may also hope that weakening Hizballah militarily could alter the domestic balance of power in Lebanon, emboldening Shi‘a critics of Hizballah and exposing it to attacks by Sunni extremists in Lebanon and Syria.

Critics within and outside Israel will undoubtedly protest the collateral damage caused by such a campaign. And a protracted conflict that leads to significant civilian casualties in Israel could increase pressure on the Israeli government to expand the mission. But as in 2006, Israel would be supported overtly by the U.S. administration, and tacitly by many Arab states, which will be rooting for Israel to strike a painful blow against Hizballah, and thus against Iranian regional ambitions.

A major conflict would also have important implications for Syria. Fighting could spread to the Golan frontier and bring Assad regime forces under Israeli fire. Hizballah could be forced to withdraw troops from Syria in order to meet an Israeli offensive in southern Lebanon, reducing its ability to support Damascus. If the group suffers major losses, its ability to render support to Iran’s policy in the region could likewise be compromised. This could encourage Syrian rebels to seize the moment and to launch a new wave of attacks on the Assad regime in the hope of regaining the initiative.

Escalation Dynamics

A number of factors inherent to the Hizballah-Israel conflict make rapid escalation likely. There are advantages to escalating faster than one’s opponent in order to seize the initiative and dictate the scope and pace of operations. Triggers could include high-casualty incidents, snowballing violence as each side ups its commitment, or domestic pressure to achieve victory. Moreover, Hizballah (and its allies in the “resistance axis,” Iran and Syria) may be encouraged by past successes against Israel (2000 and 2006) and Syria’s rebels (2011–present) to be steadfast and to take risks, believing that this has paid off in the past.

Several countervailing factors may limit escalation. Neither side seems particularly eager to risk the extensive casualties and damage that a major conflict could bring—especially Hizballah, after incurring more than 1,700 killed and several thousand wounded in Syria. Moreover, Hizballah’s ongoing Syrian commitment makes it less capable of sustained conflict with Israel. Pressure from allies could steer each belligerent away from escalation, even if it does not cause either party to end a conflict prior to achieving their military objectives.

Russia: Constraint or Enabler?

One of the chief consequences of Syria’s civil war has been the return of a major Russian military presence in the region, for the first time since the end of the Cold War. Russia now has several thousand troops in Syria, including infantry, armor, artillery, and special forces. It has between forty and fifty combat aircraft (including Su-24, Su-25, Su-30, and Su-34 strike fighters and Mi-28 and Ka-52 attack helicopters), located at Hmeimin Air Base and several forward operating bases and dispersal airfields. It also maintains a small naval presence off the coast of Syria which has, at various times, included a diesel submarine, one or two corvettes and frigates, several amphibious landing ships, and various fleet auxiliaries. Finally, Russia has created an anti-access bubble in Syria consisting of SSC-5 coastal anti-ship missiles, SS-26 Iskander ballistic missiles, and SA-22, S-300, and S-400 SAMs. All of these (except for the SA-22) are long-range systems that can cover northern Israel.

Thus far, Russia has not interfered with Israeli strikes on arm depots and convoys transporting arms from Syria to Hizballah. But given Russia’s reliance on Hizballah to prop up the Assad regime (Russian advisors reportedly respect Hizballah fighters, while holding Syrian and Iranian forces and other Shi‘a militias fighting for the regime in low regard), it might try to constrain Israel to prevent the defeat of an organization that it depends on to ensure the Assad regime’s survival. Russia would likely use diplomatic action and perhaps threats to limit Israeli operations in Syria, and it might use force if their troops were endangered or if Israeli actions threatened the stability of the Assad regime. This could lead to tensions with the United States, which will likely encourage Israel to inflict maximum damage on Hizballah. Russia would also replace Syrian (and via Syria, some Hizballah) war losses.

Missile versus Missile

Hizballah’s 150,000 rockets and missiles pose the greatest military threat to Israel. Most of these are short-range Katyusha-type rockets. But Hizballah probably has thousands of medium- and long-range rockets, such as the Iranian Fajr-3 and -5 (with claimed ranges of forty kilometers and seventy kilometers, respectively), the Syrian Khaybar-1 (100 kilometers), and the Iranian Zelzal-3 (250 kilometers), as well as missiles such as the Syrian M600—based on Iran’s Fateh-110 (250 kilometers), and SCUD-B/C/D missiles (300-700 kilometers). Israel’s military estimates that in a future war, Hizballah will be able to launch 1,500 rockets and missiles a day against it. Hizballah will likely target military facilities (such as headquarters, airfields, mobilization bases), critical infrastructure (such as power plants and petroleum storage facilities), and civilian population centers. Indeed, Nasrallah has warned Israel that Hizballah will hit critical infrastructure in a future war, including an ammonia storage facility in Haifa (whose destruction, he boasted, would lead to the death of thousands) and the nuclear reactor at Dimona, though he has generally couched these threats as a “tit-for-tat”-type response to possible Israeli actions. Thus, he has warned

For these reasons, Israel will try to destroy Hizballah’s more capable rocket/missile systems at the outset of a war, just as it did in 2006. And while Israel has rocket/missile defenses capable of dealing with the full range of threats (some 12 Iron Dome missile batteries, three Arrow-2 and -3 missile batteries, and one David’s Sling battery), Hizballah’s large rocket and missile force is likely to overwhelm Israeli defenses—at least in the early days of a conflict, if not for its duration. Hizballah might also use rockets and attack drones to suppress Israeli missile defenses, so that its M-600 and SCUD missiles (or Iranian SCUD missiles) can get through—a tactic the Houthis have used in their war with the Saudi-led coalition.

Finally, Israel’s extensive natural gas production infrastructure in the Eastern Mediterranean is also likely to be targeted. Hizballah’s acquisition of P-800 Oniks (Yakhont) anti-ship cruise missiles with a 300-kilometer range provides it with the means of hitting Israel’s offshore natural gas production facilities, as well as coastal targets such as the Hadera power plant south of Haifa.

Ground and Air Operations

Hizbollah will conduct both offensive and defensive operations. The former will include a rocket and missile blitz throughout the depth of Israel. According to Israeli intelligence estimates, Hizballah will launch up to 1,500 rockets and missiles per day against airfields, military headquarters, and critical infrastructure, dwarfing numbers fired in previous wars and saturating Israeli defenses. Hizballah cross-border attacks by means of tunnels or aerial infiltration using ultralight aircraft could also be a central feature of a future war, especially in its early days, before Israeli forces had gained ground in southern Lebanon. Hizballah will probably try to capture (temporarily) military outposts and villages in northern Israel and take prisoners and hostages in order to undermine the Israeli public’s confidence in their government and military, and to create an “image of victory.”

Hizballah will attempt to blunt the effectiveness of Israel’s air force by dispersing its massive rocket and missile forces in subterranean, one-time-use launch positions, dispersing its ground forces in civilian population centers and underground bunker complexes, and by deploying new or improved types of man-portable surface-to-air missiles such as the SA-18, and vehicle-mounted systems such as the SA-17 and SA-22. It will try to blunt any Israeli ground operations by anchoring its defenses in built-up areas along likely Israeli axes of advance, by using fortifications and underground bunker complexes, and employing camouflaged and concealed antitank missiles (like the AT-14 Kornet) and indirect fire systems (such as mortars and rocket artillery) in large numbers.

Israel offensive actions will likely consist of two major components: 1) an air campaign against Hizballah’s rocket and missile forces and supporting infrastructure throughout Lebanon (to include hardened and buried production facilities), and against anti-ship missiles along the coast; 2) a multi-division ground operation in southern Lebanon, supported by airmobile insertions, to attack Hizballah ground, rocket, and missile forces in southern Lebanon and the Bekaa Valley. There might also be a supporting operation against Hizballah forces in the Golan that could be followed by a flanking movement into eastern Lebanon via the Beirut-Damascus highway, to isolate Hizballah forces south of the highway. The limitations of airpower to effectively suppress and root out a camouflaged, concealed, and hardened rocket and missile threat (demonstrated in Lebanon in 2006 and in several Gaza operations since) make major ground operations a necessity. Israeli operations will aim to comprehensively destroy Hizballah combat forces.

Israel will likewise rely on active and passive defenses (anti-rocket/missile systems and civil defenses, respectively) to reduce the impact of Hizballah rocket and missile strikes. It will also have to be prepared to fight on its own soil in the event of cross-border penetrations. In a recent large scale exercise Israel practiced defending its border communities and evacuating civilians to a depth of nine kilometers inside its own territory. For the first time since the 1948 war, Israel may evacuate tens of thousands of residents from border communities in the north (and perhaps elsewhere), to facilitate operations to repel such penetrations, and to protect populations within range of short-range rockets.

A Cyber Dimension?

Cyber operations could figure prominently in a future Hizballah-Israel war. Israel is a global cyber power, as demonstrated by its cyberattacks (reportedly in conjunction with the United States) against Iran’s nuclear program. It is likely to integrate offensive and defensive cyber into both its battlefield activities and its efforts to disrupt those elements of Lebanon’s infrastructure used by Hizballah—although a desire to conceal the actual scope and nature of its cyber capabilities may predispose it to restraint.

Hizballah and Iran have conducted sporadic cyberattacks on Israeli critical infrastructure in recent years, usually in times of tension, such as the Israel-Hamas war in 2014. These attacks were apparently intended to harass and to warn Israel that both sides can play this game; indeed, none of these attacks disrupted or damaged Israeli critical infrastructure or govern­ment operations. Iran has shared cyber tools and know-how with Hizballah, transferring certain capabili­ties within two to four years of their introduction in the Islamic Republic.

Given Israel’s heavy reliance on information technology, Hizballah is almost certainly examining the use of cyber to disrupt Israeli rocket and missile defenses, unmanned aerial and naval systems, and critical infrastructure. Given the likelihood that Israel will strike Lebanese infrastructure that facilitate Hizballah military operations (roads, power grids, communications), Hizballah will likely try to respond in kind, in both the physical and cyber domains.

Unreliable Coalition Partners

Hizballah has proven itself an invaluable ally to Syria and Iran—helping ensure the survival of the Assad regime. But both Syria and Iran will likely limit their involvement in any future Hizballah-Israel war. Syria might facilitate the transfer of arms and the passage of Shi‘a fighters and Iranian military personnel through its territory to Lebanon, and allow Hizballah and Iran to use the Syrian Golan as a springboard for operations against Israel. But with barely enough forces to hold onto its rump state, Syria is unlikely to participate directly in such a war, though it will likely be targeted by Israel for facilitating Hizballah’s war effort.

Iran has also limited its involvement in past wars. During the 2006 war in Lebanon and the 2008-2009, 2012, and 2014 conflicts in Gaza, Iran neither intervened nor permitted Iranian volunteers to leave for the front. After Ali Akbar Velayati, senior adviser to Ali Khamenei, warned Israel in January 2013 that an attack on Syria would be considered an attack on Iran, the Islamic Republic did nothing in response to the nearly hundred subsequent Israeli strikes on weapons shipments destined for Hizballah. When Syria reportedly asked Iran to retaliate against Israel in response to an Israeli strike in February 2013, Iran reportedly refused to do so. Finally, throughout its intervention in Syria, Iran has tried to limit its own exposure by offloading risks and burdens on its proxies, using them as cannon fodder, and fighting to the last non-Iranian Shi‘a proxy whenever possible.

Yet, Iran—emboldened by its success in securing the survival of the Assad regime—might take chances in a future war that it was loath to take in the past, facilitating Hizballah operations in Lebanon and the Syrian Golan, transporting Shi‘a militiamen to the front, and perhaps allowing IRGC advisors to participate in combat. Thus, there is a greater potential for a clash involving Iran and Israel than in previous wars. (Indeed, an IRGC general was killed in an Israeli air strike during a tour of the Syrian Golan with Hizballah personnel in January 2015.)

Hizballah might be reinforced by militias belonging to Iran’s Shi‘a legion. For instance, a pro-Tehran Iraqi militia, Harakat Hizballah al-Nujuba, recently created a group dedicated to the “liberation” of the Golan Heights from Israel. Israeli intelligence assesses that Iran controls perhaps 40,000 Syrian, Iraqi, Afghani, and Pakistani militiamen, some of which might be dispatched to support Hizballah in wartime. The military utility of these forces, however, would likely be limited: most are not well trained, and the Afghans and Pakistanis don’t speak Arabic. They would probably backfill positions vacated by Hizballah fighters mobilized to fight at the front, or fulfill rear area security and civil defense tasks. And because they would have to travel a ways to get to Lebanon, their convoys could be interdicted en route.

Finally, there is always the possibility of a Gaza “excursion” during a Hizballah-Israel war. In the past, Hamas has exploited tensions between Hizballah and Israel to take pot shots against Israel, and it is likely to do so again in the future. During past conflicts with Israel, Hamas has also asked Hizballah to open a second front, to relieve pressure on Gaza. Each time, however, Hizballah refused. In light of the recent ascendancy of a hard-line Hamas military leadership and the subsequent mending of ties between Hamas and Iran, a greater degree of coordination between the two may be possible, though each will act in accordance with their own interests.

Implications: The Wages of War

A war will produce significant military and civilian losses and widespread destruction on both sides. Ground combat in southern Lebanon and perhaps northern Israel will probably produce the most military casualties, with air and rocket/missile strikes accounting for the majority of civilian losses. Hizballah has created an extensive military infrastructure that is integrated with the civilian infrastructure in Shi‘a-majority regions, making heavy civilian losses almost inevitable. Israeli commanders have already indicated that operations against Hizballah will not be constrained by the presence of civilians. In an October 2008 interview, the chief of Israel’s Northern Command (now Chief of Staff of the armed forces) Major General Gadi Eisenkot announced what subsequently became known as the “Dahiya Doctrine,” stating that in a future war:

Shi‘a civilians will be unable to flee in large numbers because they will be unwelcome elsewhere (unlike in 2006) due to Lebanon’s sectarian polarization, and will suffer heavy losses. Moreover, Israel will probably target Lebanon’s critical infrastructure—roads, bridges, and communications facilities that could contribute to Hizballah’s war effort—as well as the Lebanese Armed Forces, which cooperates with Hizballah and shares intelligence with it.

Such a war will cause widespread social and economic dislocation in both Lebanon and Israel. This could greatly complicate Hizballah’s domestic political standing, as many Lebanese will blame it for the war and its consequences. In such circumstances, it will be difficult for Hizballah to proclaim a “divine victory” as it did in 2006, regardless of its military achievements, and efforts to create an “image of victory.” It is not too difficult to imagine Nasrallah having to once again admit, as he did in a post-2006 war interview, that war with Israel was a mistake:

An enfeebled Hizballah, moreover, will be less capable of helping prop up the Assad regime, and Russia and Iran will have to take up the slack to ensure the regime’s survival. As for Israel, should it once again prove incapable of dealing Hizballah a decisive blow, it is likely to experience political recriminations and turmoil, as have occurred after past wars.

For Israel, a war of this magnitude and intensity will have major political, economic, and social consequences well beyond any military outcomes. It would mark the first time since the War of Independence that Israel, throughout its territory, would be a major battleground, with the population and infrastructure exposed to direct, and likely sustained, attack. Even given likely Israeli successes against Hizballah and improvements in civil defense, this would be a true test of the country’s resilience.

Policy Recommendations

It remains to be seen whether Hizballah and Israel can avoid another war; hopes the parties would do so prior to the 2006 Lebanon war and the 2009 and 2014 Gaza conflicts proved wrong. Moreover, the next Hizballah-Israel war will be much more intense and destructive than their 2006 conflict; much of Lebanon and all of Israel will likely be targeted. This will create pressure on both parties to escalate in order to achieve a decisive outcome; to prolong the fighting in order to exhaust the enemy; or to achieve symbolic successes that could permit a cease fire on honorable terms.

Clearly, the overwhelming imperative for Washington is to prevent such a war in the first place. Yet, U.S. policy in recent years may have made such a war more likely; by not providing more robust support to the non-Salafist opposition in Syria, the United States made the success of the Assad regime and its allies more likely. This may embolden them to build on their military successes and overreach—just as Hizballah’s success in forcing Israel out of Lebanon in 2000, and Hamas’s success in forcing Israel from Gaza in 2005, caused Hizballah and Hamas to engage in provocations that led to additional wars. Accordingly, Washington should quietly warn Hizballah, Iran, and Syria against actions that could lead to war, and signal that it will not restrain Israel if Hizballah acts recklessly or provocatively.

Efforts to prevent another Hizballah-Israel war should be nested within a broader U.S. policy of pushing back against and imposing costs on Iran for its destabilizing regional policies. Washington no longer seems interested in training and equipping the remnants of the non-Salafist Arab opposition. However, a revived train and equip program—not to overthrow the Assad regime but to deter pro-regime forces and keep them tied down in Syria—might ensure the success of the de-escalation zones and help avert another Hizballah-Israel war.

Specifically, such a program should strive to create a military balance between the remaining rebel enclaves and the regime of Syrian President Bashar al-Assad, to shore up shaky cease fires, prevent new mass refugee flows, and forestall shifts in the military balance—as the regime and its allies rearm—that could encourage pro-regime forces to renew attacks on rebel-held areas. Tying down pro-regime forces (including Hizballah) in Syria will also limit their ability to make trouble elsewhere in the region, and thereby reduce the prospects for a ruinous Hizballah-Israel war. Washington seems averse to such a renewed train and equip effort, but the result of such diffidence might be the very outcome it is trying to avoid.

In the event of war, the U.S. should provide Israel political cover and buy for it the time needed to strike a decisive blow against Hizballah—Iran’s foremost regional proxy. The United States should continue to provide Israel with the military means to sustain an intense and perhaps prolonged war against Hizballah. The United States should work to ensure that Israeli targeting minimizes civilian casualties and damage to civilian infrastructure in Lebanon—even if Hizballah’s modus operandi makes such collateral damage inevitable. It should quietly warn Syria and Iran to avoid provocations that could further escalate a conflict—such as opening a second front on the Syrian Golan, the deployment of Shi‘a militias and Iranian “advisers” there, or the launch of Iranian missiles—and it should indicate that it will assist Israeli efforts to disrupt or counter these actions.

Finally, the United States should support termination of the conflict only when conditions for an enduring cease-fire have been met. Making clear to Hizballah that the United States will not seek a premature halt to a war that could make Hizballah—and the Assad regime—more vulnerable to their local Arab rivals and enemies (some of whom the United States should be arming for its own reasons—per above), may be the best way to prevent such a war in the first place.