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September 20, 2024
A day after Hamas (a U.S.-designated foreign terrorist organization, or FTO) led the October 7, 2023, attacks against Israel that began their ongoing war, Lebanese Hezbollah (another FTO) started shooting rockets and missiles across Lebanon’s border into Israel in a show of solidarity with Hamas. Since then, Hezbollah and Israel have regularly exchanged fire across the border, in the latest phase of their adversarial history. Iran appears to regard Hezbollah as its most capable partner in its “axis of resistance” versus Israel, and debate persists regarding the degree to which Hezbollah acts independently or as Iran’s proxy.
Since July 2024, Israel-Hezbollah violence has become more volatile than in the preceding nine months. Separate U.S.-supported efforts to pause or halt fighting in Gaza and at the Lebanon border have not produced a clear breakthrough. September 2024 covert attacks attributed to, but not claimed by, Israel resulted in the explosion of electronic devices reportedly acquired by Hezbollah. The explosions reportedly killed tens and injured thousands in Lebanon, including some civilians. Hezbollah has vowed to retaliate, and Israel has announced a shift of some of its military forces from Gaza to the Lebanese border area.
Figure 1. Hezbollah’s Rocket and Missile Arsenal
Source: Center for Strategic and International Studies, March 2024 (citing various sources).
Subsequent signs of escalation, including an Israeli airstrike on September 20 in Beirut that the Israeli government says killed several senior Hezbollah officials, may increase the prospects of broader war. Hezbollah’s large arsenal of drones, rockets, and missiles (see Figure 1) could threaten Israeli strategic sites and population centers, and Israel could strike throughout Lebanon, with potentially devastating consequences to its institutions and society. Wider-scale war could prompt Israel to seek additional U.S. material support or direct military involvement, with major implications for U.S. national security interests in the region.
Even if Hezbollah were to agree to halt attacks, perhaps in connection with an Israel-Hamas cease-fire, Israeli leaders insist that Hezbollah’s fighters must be kept back from the border to mitigate the threat of an October 7-style attack there. Violence to date has displaced some 60,000 Israeli and 95,000 Lebanese civilians from their homes near the border. In September, Israel’s cabinet added the goal of returning evacuated Israelis to its official war objectives. While Israel retains conventional military superiority in the region, some Israeli and U.S. analysts have assessed that Hezbollah could be capable of overwhelming, depleting, or targeting Israeli air defense systems via massive projectile volleys—some of which may include precision guidance. Dismantling Hezbollah’s military capacity in Lebanon may be more difficult than doing so against Hamas’s forces in Gaza, partly due to Hezbollah’s considerable defensive capabilities in Lebanon’s varied terrain and the wider geographic dispersal of Hezbollah’s assets and personnel.
Israel-Hezbollah: Selected Historical Events
1982- 1985
Israel’s 1982 invasion of Lebanon and related U.S. and French military involvement trigger resistance from some factions in Lebanon’s ongoing civil war. Elements from Lebanon’s Shia community—including some responsible for fatal attacks on U.S. and French installations—establish Hezbollah with help from Iran’s Islamic Revolutionary Guard Corps.
1985 Israeli military withdraws from central Lebanon, but maintains a zone of control in predominantly Shia- populated southern Lebanon with a Lebanese partner force. Hezbollah becomes the main node of resistance to the Israeli presence.
1992- 1994
Hezbollah bombings of Israel’s embassy (1992) and a Jewish community center (1994) in Argentina kill 29 and 85 people, respectively.
1996 Hezbollah attacks on Israel and Israeli forces trigger the 17-day Israeli “Operation Grapes of Wrath,” which kills more than 200 Lebanese.
2000 Israel withdraws from southern Lebanon, leading Hezbollah to claim victory. Hezbollah maintains that Israel still occupies Lebanese territory in disputed parts of the tri-border (Israel-Lebanon-Syria) area.
2006 Israel and Hezbollah engage in a 34-day war after a fatal Hezbollah attack and hostage-taking on an Israeli military position. In the war, some 160 Israelis and 1,200 Lebanese are killed. After the war, UN Security Council Resolution 1701 calls for all non-Lebanese army forces to withdraw north of the Litani River; Hezbollah does not comply and starts to rearm.
Israel and Lebanese Hezbollah: Current Violence and Potential Escalation
https://crsreports.congress.gov
2011- Present
Hezbollah helps Iran defend regime of Bashar al Asad in the Syrian civil war. Territorial links from Iran to Lebanon through Iraq and Syria facilitate greater Iranian weapons supply (including precision-guided missiles) to Hezbollah, provoking regular Israeli military strikes in Syria starting around 2012 to prevent or delay these transfers.
2023- Present
Hezbollah commences cross-border fire with Israel after outbreak of Israel-Hamas war; as of September 2024, more than 500 Lebanese and over 30 Israelis have reportedly been killed in various attacks.
Events Since July 2024 Israel-Hezbollah violence has intensified after a rocket fired from Lebanon on July 27 reportedly killed 12 young Druze people in the Golan Heights. U.S. and Israeli officials said Hezbollah was responsible despite the group’s denial. On July 30, an Israeli drone strike in Beirut killed Hezbollah senior commander Fuad Shukr, who Israel blamed for the Golan Heights attack.
On August 25, as Hezbollah apparently prepared a retaliatory strike for Shukr’s killing, Israel announced it had acted on intelligence to preempt the retaliatory attack by using over 100 aircraft to strike Hezbollah launchers in Lebanon. That same day, Hezbollah fired hundreds of rockets and drones into northern Israel. Hezbollah claimed its operation was successful in targeting Israeli military and intelligence bases, but Israel said no bases were damaged. On September 17-18, thousands of pagers, walkie-talkies, and other electronic devices exploded across Lebanon, reportedly killing more than 30 people and injuring close to 3,000 (reported casualties included some children and other civilians). While Israeli officials have not commented, open sources suggest that Israeli military and intelligence units may have planted explosive material in devices ordered for Hezbollah operatives, and then triggered these devices. Some reports indicate that Israel may have set off the devices due to concerns that Hezbollah would otherwise discover the plot. Some current and former Israeli officials reportedly argue that Israel seeks to raise the cost to Hezbollah of insisting that it will continue to fight at least until a cease-fire in Gaza.
Observers speculate on whether these incidents, including the Israeli airstrike that reportedly killed senior Hezbollah leaders in Beirut on September 20, may be a prelude to an Israeli offensive into Lebanon. Such an operation, or efforts by Hezbollah to attack sensitive Israeli targets, could escalate the conflict further. Strategic Considerations Israel may consider how it can optimally remove the threat of an October 7-style invasion from Hezbollah and return evacuees to the north; degrade Hezbollah’s capabilities; overcome potential vulnerabilities in Israeli defenses; and maintain resources, personnel, and international support despite strains from war with Hamas. Hezbollah may consider how it can optimally target Israel—in concert with Iran and its other allies—without endangering its capabilities; and maintain its domestic military and political position.
Issues for Congress Diplomacy and U.S. support for Lebanese forces. U.S. officials continue to seek an arrangement that would keep Hezbollah back from the border so that Israeli evacuees can return, and reduce chances of a broader war. Media reports suggest that U.S.-French diplomatic proposals envision the Lebanese Armed Forces (LAF, which Congress has supported for many years with $150 million annually) and the UN Interim Force in Lebanon (UNIFIL) patrolling any Lebanese area from which Hezbollah withdraws. However, the LAF may not be willing or able to counter Hezbollah, raising questions about how Hezbollah can be kept from the border area. In June, Israeli Prime Minister Benjamin Netanyahu stated that any diplomatic arrangement “will include the physical distancing of Hezbollah from the border, and we will need to enforce it.” While Biden Administration officials have repeatedly emphasized a desire to de-escalate tensions between Israel and Hezbollah, events since July appear to have increased prospects of escalation. Previously, open sources reported that Israel’s leadership was considering a “massive strike” against Hezbollah shortly after Hamas’s October 2023 attacks, but Prime Minister Netanyahu reportedly decided against it after U.S. officials urged him to stand down. U.S.-Israel security cooperation and arms sales. For more than 50 years, the United States has been the main external source of political and material support for Israel’s self-defense, with Congress enacting regular and supplemental appropriations (over $12.6 billion in FY2024). Since the outbreak of conflict in October 2023, Members of Congress have differed with one another and the Administration on the nature and timing of arms exports to Israel, with some Members advocating greater scrutiny or conditions, and others calling for the Administration to expedite Israeli requests given the country’s security environment, in which threats could rapidly escalate. Since FY2020, Congress also has appropriated more than $120 million toward a cooperative U.S.-Israeli Counter Unmanned Aerial Systems program, including directed energy (laser) capabilities. Some Israeli analysts say developing these laser capabilities is critical to countering adversary drone barrages without exhausting Israel’s inventory and incurring hundreds of millions of dollars in annual replenishment costs. Direct U.S. military involvement and protection of U.S. citizens. Various scenarios—including potential Israeli preventive strikes or counteroffensives against Hezbollah— could lead to situations in which U.S. forces deployed to the region under official orders to assist with Israel’s defense might become enmeshed in conflict with Hezbollah or Iran, either within or outside of Israeli sovereign space. Some observers comment on possible tension between Israel’s insistence on maintaining independence of action and its appeal for U.S. help when it encounters certain threats. The two countries do not have a formal defense treaty. Congress might debate authorization of the use of military force and/or questions of strategy, operations, deployments, and appropriations, and whether U.S. actions to assist Israel’s defense serve U.S. interests and comply with U.S. and international law. Additionally, reports indicate that the Administration has explored contingencies to evacuate tens of thousands of U.S. citizens estimated to be in Lebanon.
Israel and Lebanese Hezbollah: Current Violence and Potential Escalation
https://crsreports.congress.gov | IF12770 · VERSION 1 · NEW
Jim Zanotti, Specialist in Middle Eastern Affairs
Clayton Thomas, Specialist in Middle Eastern Affairs
IF12770
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