Killing Nasrallah and the Law of Armed Conflict

Last Friday, the Israel Defense Forces (IDF) conducted air strikes against a Hezbollah command and control bunker in Beirut’s Dahiyeh suburbs, which was located under an apartment complex. The attack, which followed IDF warnings for civilians to evacuate the area, killed the group’s Secretary-General, Hassan Nasrallah, who had led Hezbollah for over three decades (see briefing here).

The Nasrallah strike was only the most recent in a series of Israeli attacks against “high-value targets” (HVT) since October 7th of last year. Such attacks are often labeled “decapitation strikes,” denoting their purpose of disrupting enemy command and control by removing key leaders.

This was not the first such IDF attack against Hezbollah. Other decapitation strikes include those targeting Ibrahim Aqil, Hezbollah’s acting commander of the Radwan Force and member of the Jihad Council; Faud Shukr, a military leader close to Nasrallah and member of the Jihad Council; Muhammad Nasser, a senior leader who commanded Hezbollah’s western sector in southern Lebanon; and Taleb Abdullah, commander of the central region along the border. Relatedly, Israel has killed Iranian leaders involved in supporting Hezbollah operations, such as Brigadier General Mohammad Reza Zahedi, a senior commander of the Islamic Revolutionary Guard Corps (IRGC) Quds Force, and his Deputy, Brigadier General Mohammad Hadi Haji-Rahimi.

Similar operations have targeted Hamas leadership, including Muhammad Deif, head of the al-Qassam Brigades and mastermind of the October 7th attack; Ismail Haniyeh, Chairman of the Hamas Political Bureau; and Saleh al-Arouri, the Deputy Hamas Chief and founder of its military wing. And Israel is not alone in conducting decapitation strikes. The United States, for instance, accelerated the timing of Operation Desert Storm in 2003 in a failed attempt to kill Saddam Hussein. More recently, the United States has regularly turned to drone strikes for decapitation purposes. Their victims include Anwar Al-Awlaki, the U.S.-born Al-Qaeda propagandist; Qasem Soleimani, commander of Iran’s Quds Force; and Ayman al-Zawahiri, the leader of Al-Qaeda following Osama bin Laden’s death.

In this post, I examine the law of armed conflict (LOAC) rules that governed the attack on Nasrallah (and, by extension, decapitation strikes more generally). I do not deal with the ad bellum issue of whether Israel was entitled to conduct the attack in self-defense on Lebanese territory. Nor do I examine whether the operation triggered an international armed conflict between Israel and Lebanon. The sole issues addressed in this post are whether Nasrallah was a lawful target and whether the strike was conducted in compliance with the obligation to take precautions in attack and the rule of proportionality.

Finally, note that although the operation was conducted during a non-international armed conflict against the leader of a non-State group, the customary law targeting rules discussed below apply equally to the targeting of State leaders during an international armed conflict.

The Context

As will become apparent in the legal discussion that follows, assessing whether the strike complied with LOAC requires an understanding of Hezbollah’s military wherewithal, the organization’s structure, and Nasrallah’s role in the group. This is because context always drives clear-eyed analysis in the law of targeting.

Designated a terrorist group by the United States in 1997, Hezbollah has a long history of attacking Israeli and American targets around the world, including the infamous 1983 suicide truck bombings of the U.S. Embassy and Marine barracks in Beirut that killed 241 U.S. military personnel (see here, p. 275). But beyond individual acts of terrorism, Hezbollah also fields a robust conventional force. Its military wing, “Islamic Resistance” (Al-Muqawama al-Islamiyya), numbers well over 20,000 fighters (with another 20,000 reservists) and consists of relatively standard military units (rocket and missile, air defense, naval, armored, intelligence, drone, etc.). Of note in the Israeli context are Radwan, a special forces group that conducts cross-border operations, and the External Security Organization (Islamic Jihad), which is responsible for overseas terrorism. Hezbollah has attacked Israel constantly since Hamas’s horrific attack on October 7 of last year. In particular, it has launched more than 8,000 rockets against Israeli military targets and civilian population centers. Over 150,000 rockets and missiles remain in its arsenal.

At the same time, Hezbollah is a robust political organization. Together with the Amal Movement, it is the Shia community’s primary representative in the Lebanese Parliament, and members of Hezbollah have served in the Lebanese Cabinet. Moreover, the organization provides important social services in Shia-majority areas.

As Secretary General of Hezbollah, Nasrallah shouldered both political and military responsibilities. He oversaw its Shura Council with its five sub-councils. Four perform civilian political, executive, parliamentary, and judicial functions. The fifth, the Jihad Council, controls its military activities. In his role as Secretary-General, Nasrallah approved significant and sensitive military and terrorist operations.

The Law

Whether Nasrallah’s killing was a “measure of justice,” as President Biden has suggested, is legally irrelevant. Vengeance, retaliation, retribution, and even justice never serve as a legal basis for killing an individual during an armed conflict. Instead, decapitation strikes and other HVT attacks are justifiable only when conducted in compliance with LOAC’s targeting rules.

Lawful Target

In every strike directed at an individual, whether an HVT or a foot soldier, the first question is whether their status or activities qualify them for attack. There are three categories of targetable persons: combatants, organized armed group (OAG) members, and civilians directly participating in the hostilities (DPH). The reason their attacker targets them has no bearing on whether they qualify as lawful targets. Accordingly, the fact that a strike may decapitate the enemy and thereby sow great confusion does not, standing alone, render an individual subject to attack.

The first of the three categories does not apply in Nasrallah’s case because combatancy is a concept limited to international armed conflict. However, for the sake of completeness, it is useful to note that combatants include members of a State’s armed forces other than medical and religious personnel; members of a militia or volunteer corps that “belongs” to a State, with certain conditions; and members of a levée en masse (Geneva Convention III, art. 4). Such individuals are targetable around the clock based on their status (so-called “status-based targeting”) regardless of the activity in which they are engaged.

Members of OAGs, the second category, are also lawfully targetable at any time (subject to LOAC’s other targeting rules), including during a non-international armed conflict like that between Israel and Hezbollah. Hezbollah is a “mixed group” in the sense that it performs both civilian and military functions. As I explained in an earlier Articles of War post, if a group has distinct subdivisions that engage in purely civilian functions, the entire group cannot qualify as an OAG. The fact that Hezbollah has sections dedicated to political and social matters, therefore, precludes characterizing it in its entirety as an OAG. Instead, only its military wing comprises the OAG, and accordingly, only the wing’s members are targetable based on their status.

This raises the question of whether Nasrallah was a member of that OAG. In this regard, there is no requirement for formal membership in the group. Such a requirement would be counter-factual, for many OAGs lack a formal membership structure mirroring that of a conventional armed force. Rather, the key is “functional membership,” which may be indicated by formal membership but need not be. As the U.S. Department of Defense (DoD) Law of War Manual explains, “An individual who is integrated into the group such that the group’s hostile intent may be imputed to him or her may be deemed to be functionally (i.e., constructively) part of the group, even if not formally a member of the group” (§ 5.7.3.2).

Senior leaders of a non-State group with a military wing do not necessarily qualify as OAG members based on their position. This is so even if they engage in decision-making at the strategic level of war, as in deciding whether and when to initiate hostilities. As I have observed before, “Surely all national leaders who occupy a position at the top of the military chain of command—whether legislative, constitutional, or de facto—are not targetable members of the armed forces. If this were the case, compliance with the core democratic principle of civilian control of the military would render most national leaders subject to attack.” The U.S. DoD Law of War Manual is in accord: “Leaders who are not members of an armed force or armed group (including heads of State, civilian officials, and political leaders) may be made the object of attack if their responsibilities include the operational command or control of the armed forces” (§ 5.7.4).

Thus, a leader who enjoys the authority to control military actions at the operational or tactical level of war and exercises that authority on a recurring basis is fairly characterized as a member of the OAG in question. Nasrallah would qualify on this basis, for, as explained above, he regularly approved or disapproved of Islamic Resistance conventional operations and acts of terrorism. As an aside, I presume that advocates of the International Committee of the Red Cross (ICRC) “continuous combat function” approach to OAG membership, which the United States rejects (correctly, in my opinion), would presumably come to the same conclusion on the basis that approval of attacks is a combat function.

I would add that I find the regularity of a leader’s involvement in military operations legally significant. One who is not a formal member of the OAG conducting hostilities but who wields the authority (de jure or de facto) to control military operations does not qualify as a targetable member if exercising that authority only infrequently. That leader is not “integrated” into operational or tactical levels of war operations.

This leads us to the third basis for targetability, direct participation in the hostilities. It is well-accepted as a matter of treaty and customary LOAC in both international and non-international armed conflict that individuals who “directly participate in the hostilities” lose their protection from attack “for such time” as they so participate (AP I, art. 51(3); AP II, art. 13(3); ICRC, Customary IHL study, rule 6; U.S. DoD, Law of War Manual, § 5.8). This begs the question of whether Nasrallah would have been targetable as a direct participant even if he was not a functional member of Hezbollah’s fighting wing.

There is no question that approving attacks qualifies as direct participation in the hostilities. For example, the UK Manual of the Law of Armed Conflict observes, “Those who plan or decide upon attacks are the planners and commanders and they have a duty to verify targets, take precautions to reduce incidental damage, and refrain from attacks that offend the proportionality principle” (§ 5.32.9, emphasis added). The U.S. DoD Law of War Manual is even more to the point. Among its examples of direct participation are “planning, authorizing, or implementing a combat operation against the opposing party, even if that person does not personally use weapons or otherwise employ destructive force in connection with the operation” (§ 5.8.3.1). So, whether Nasrallah often approved operations or did so on only a periodic basis, he participated in the hostilities against Israel at some point.

But if so, did the strike occur while he was participating, that is, was it in compliance with the “for such time” limitation? This temporal requirement has long been the source of disagreement, with the United States, correctly, in my view, taking the position that repeated instances of direct participation amount to ongoing participation until the individual definitively desists (U.S. DoD, Law of War Manual, § 5.8.4.2). The ICRC takes a more restrictive view, according to which each instance must be evaluated individually, thus advocating a so-called “revolving door” of targetability.

But here, the attack occurred while Nasrallah was in a command-and-control bunker meeting with other high-ranking Hezbollah members who had gathered to discuss operations against Israel, which he would have to approve. Thus, it would seem clear that by either approach, Nasrallah was directly participating in the hostilities at the time of this strike.

Precautions in Attack and Proportionality

The attack that killed Nasrallah was massive. It reportedly used multiple 2,000-pound bombs to generate a “series of timed, chained explosions to penetrate the subterranean bunker” (on weaponeering in an urban environment, see here). As a result, at least four buildings collapsed, and according to Lebanon’s Health Ministry, not less than 11 people died, and 108 were wounded. These numbers may rise.

The LOAC precautions in attack obligation requires an attacker to provide a warning when its attack may “affect” the civilian population, unless circumstances do not permit (U.S. DoD, Law of War Manual, § 5.11.5; ICRC, Customary IHL study, rule 20). Warning is not practicable when targeting individuals, for they will flee when learning of the warning. In such cases and to the extent they are feasible, general warnings to leave the affected areas, like those issued by the IDF, suffice.

Given the intensity of the attack into a residential area, the central precautions in attack question is whether the IDF complied with the requirement to consider alternative targets, weapons, and tactics to minimize civilian harm (U.S. DoD, Law of War Manual, § 5.11; ICRC, Customary IHL study, ch. 5). I find it challenging to think of alternatives to the tactics and weapons the IDF used given that the physical target was a hardened bunker 60 feet underground. Moreover, the individuals whom the IDF was targeting were going to great lengths to keep from being located. Thus, their presence represented a fleeting opportunity to conduct an attack that would both destroy the bunker and kill senior Hezbollah military leaders, including Nasrallah. Indeed, the method of attack, in which “each blast pave[d] the way for the next one,” was surgically crafted for that specific target.

This leaves the question of compliance with the rule of proportionality, which prohibits conducting attacks that are expected to cause incidental loss of civilian life, injury to civilians, or damage to civilian objects (collateral damage) that is excessive in relation to the concrete and direct military advantage the attacker anticipates gaining (U.S. DoD, Law of War Manual, § 2.4; ICRC, Customary IHL study, rule 14). Proportionality is often a fraught issue when assessing individual strikes.

In this case, the expected collateral damage was extensive because of the weapons used and the target’s location, a residential area. Still, this fact alone does not render the strike disproportionate. The anticipated military advantage must also be considered.

With respect to military advantage, the attack’s effects are what matter. In this regard, reasonable minds differ over whether decapitation strikes are operationally and strategically sensible. Those who minimize their value typically note that, over time, leaders who have been killed will be replaced, sometimes by someone more competent. But even if that is true, the short-term benefits of a successful decapitation strike are almost always contextually high because of its immediate disruption of command and control.

Sensitive to this operational reality, the IDF was reasonable in concluding that taking out senior leaders like Nasrallah and Karaki would immediately create chaos within Hezbollah’s military operations. Synergistically enhancing this anticipated effect was the fact that the pager and handheld radio attacks and the recent targeting of other senior Hezbollah commanders had already disrupted command and control. Disrupting that command and control as the IDF ramped up its campaign against Hezbollah was especially valuable.

The net result is that the IDF is able to operate well within Hezbollah’s OODA loop, affording it an exceptional asymmetrical advantage over its enemy. So, whatever one may believe about the strategic sensibility of killing Nasrallah or the general effectiveness of decapitation strikes over time, the military advantage the IDF anticipated gaining from the attack was extremely high, and accurately so.

But was the anticipated military advantage high enough to keep the expected collateral damage from reaching the “excessive” threshold? As I have observed before, LOAC rules like proportionality are meant to balance military and humanitarian considerations. Of course, perspective inevitably causes the observer to lean in one direction or the other; I am not immune to this tendency. But considering the significant and immediate effect on the ability of Hezbollah’s military wing to mount effectively commanded and controlled attacks against Israeli military and civilian targets, I believe it is reasonable to conclude that the rule of proportionality did not prohibit the attack.

Concluding Thoughts

All sides have violated the law of armed conflict at some point in Israel’s conflicts with Hamas and Hezbollah. Indeed, this is the case for most conflicts. But the IDF’s attack on Hassan Nasrallah does not appear to have done so. Nasrallah was targetable because he qualified as a member of an organized armed group based on his role in approving Hezbollah attacks against Israeli military and civilian targets. Even if this were not the case, he was directly participating in hostilities at the time of the strike and was, therefore, subject to attack.

As to how the operation was conducted, I have difficulty imagining alternative weapons or tactics for striking the bunker, which is itself a military objective, in which Nasrallah was located. And although proportionality assessments are notoriously difficult given the inherent ambiguity of the rule, the immediate military advantage that the IDF would gain through the destruction of the bunker and the death of Nasrallah and other Hezbollah military wing leaders rendered the IDF’s conclusion that the collateral damage expected to result would not be excessive relative to that advantage reasonable.

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Michael N. Schmitt is the G. Norman Lieber Distinguished Scholar at the United States Military Academy at West Point. He is also Professor of Public International Law at the University of Reading and Professor Emeritus and Charles H. Stockton Distinguished Scholar-in-Residence at the United States Naval War College.

Photo credit:  IDF Spokesperson’s Unit