Guest Post: “Civilians Who Take a Direct Part in Hostilities: Application to Israel and Gaza”

Today we introduce a new contributor to Lawfire®, Air Force Reserve Lt Col Jay Jackson.  Writing in his personal capacity Lt Col Jackson, gives us something of a primer on the concept of “direct participation in hostilities” as viewed through the lens of the International Committee of the Red Cross (ICRC).  As Lt Col Jackson point out, the DoD Law of War Manual (July 2023) takes a rather different view of parts of this area of the law as do other experts (see e.g., here and here).

By unpacking the ICRC perspective and making it more readily understandable through his clear and concise writing, Lt Col Jackson makes a key contribution.  Since the ICRC interpretation is the version accepted by many countries, to include some U.S. allies, it is vitally important to understand it, and Lt Col Jackson helps us do just that.

Civilians Who Take a Direct Part in Hostilities: Application to Israel and Gaza

by Lt Col Jay Jackson, USAFR*

Early on the morning of Saturday, October 7, 2023, on the Jewish holiday of Simchat Torah, 1,500 members of the terrorist groups Hamas and Islamic Jihad breached the barriers that separate Israel from the Gaza strip.  The so-called “smart wall” which was supposed to prevent just this sort of surprise attack was ineffective, and the unknowing and unprepared military defense was quickly overwhelmed. 

By nightfall, the attackers had killed 1,100 civilians and taken 229 others back to Gaza as hostages.  Israel has responded forcefully, including air and artillery strikes on more than 7,000 targets in the three weeks following the attack.

On October 28, Israeli Prime Minister Benjamin Netanyahu announced the operation’s second phase:  a ground assault within Gaza itself.  That operation has resulted in thousands of deaths—most of them, it is reported, are civilians, including children.

The attack and its aftermath have prompted some bold (if head-scratching) comments about just who in this conflict might be a combatant.  While some statements may be intuitively rejected, the complex legal, operational, and political environment in Israel and Gaza calls for more careful examination of the law concerning protection of civilians during armed conflict and, specifically, when civilians may be intentionally attacked. 

(To emphasize, this is an article about when civilians may be intentionally targeted.  Other rules pertaining to the law of armed conflict—concerning proportionality, the taking of hostages, human shields, the duty to warn, use of certain weapons, etc.—are highly relevant to the conflict but not discussed here.) 

Protection of Civilians under the Law

Under international law, “innocent civilians must be kept outside hostilities as far as possible and enjoy general protection against danger arising from hostilities.”  There is universal agreement that civilians must be protected from attack during armed conflict.  During the drafting of the four Geneva Conventions of 1949—generally regarded as foundational authorities for the modern law of armed conflict—“discussions were dominated by a common horror of the evils caused by [World War II] and a determination to lessen the sufferings of war victims.”  

The Geneva Conventions built upon a growing body of international humanitarian law, including the Hague Conventions of 1907, which included a provision prohibiting the “attack or bombardment, by whatever means, of towns, villages, dwellings, or buildings which are undefended.” 

These treaties have since been cemented into “customary international law”—that is, through extensive and uniform state practice, “[s]tates must never make civilians the object of attack” independent of the aforementioned treaties and whether individual nations or armed groups have acceded to them.

The protection of civilians is not absolute, however—it exists only “unless and for such time as” a civilian “takes a direct part in hostilities.”  In other words, the law of armed conflict attempts to distinguish the non-combatant civilian trying to survive an armed conflict from the civilian who has decided to give up that protection and directly participate in the armed conflict.  

The Israel Defense Forces (IDF) itself commits to only striking “persons who are members of organized armed groups or civilians directly participating in the hostilities.”  Unfortunately, none of the treaties that discuss protection of civilians actually defines what it means to take a “direct part in hostilities.”

When Civilians are not Protected

In 2009, the ICRC published its Interpretive Guidance On The Notion Of Direct Participation In Hostilities Under International Humanitarian Law.  In many instances, the ICRC Guidance serves as a starting point from which nations, academics, and non-governmental organizations begin their own interpretation of “direct participation in hostilities,” though there is by no means universal agreement with its conclusions. 

The U.S. Department of Defense Law of War Manual, for example, diverges from the ICRC’s interpretation of “direct participation in hostilities” in a number of key areas, as do other experts on the law of armed conflict.  Some, but not all, of these disagreements are described below.  I employ the ICRC Guidance here, however, as one useful framework through which to assess protection of civilians in Israel and Gaza in 2023. 

Under the ICRC Guidance, a civilian must satisfy three requirements in order to be found to be taking a “direct part in hostilities,” thereby forfeiting their protected status:

    1. An act by the civilian must be likely to adversely affect the military operations or military capacity of a party to an armed conflict or, alternatively, to inflict death, injury, or destruction on persons or objects protected against direct attack.
    2. There must be a direct causal link between the act and the harm likely to result either from that act, or from a coordinated military operation of which that act constitutes an integral part.
    3. The act must be specifically designed to directly cause the required threshold of harm in support of a party to the conflict and to the detriment of another.

These three requirements are referred to as “threshold of harm,” “direct causation,” and “belligerent nexus,” respectively.

    1. Threshold of Harm

Under the ICRC Guidance, before civilians lose the protections afforded them under international law, the likely harm resulting from their hostile act must exceed a certain threshold.  This includes “harm of a specifically military nature”—that is, acts which are likely to kill or injure military personnel, damage military objects, or impede military operations or capacity.  Acts that would exceed the threshold of harm also include “death, injury, or destruction on persons or objects protected against direct attack,” like the October 7 attacks by Hamas on Israeli civilians.  

On the other hand, the ICRC views support activities like “the building of fences or roadblocks, the interruption of electricity, water, or food supplies, the appropriation of cars and fuel, the manipulation of computer networks, and the arrest or deportation of persons” as falling short of this threshold of harm since, in the absence of adverse military effects, they do not “cause the kind and degree of harm required to qualify as direct participation in hostilities.” 

But applying the threshold of harm to civilians in the context of “Gaza tunnel entrances [which] are hidden under houses, mosques and schools” demonstrates the difficulty of the analysis in this conflict in particular.  What role do civilians play in concealing, building, protecting, or using the tunnels?  What role do the tunnels play in the conflict—command centers, medical facilities, lines of communication, points of ingress and egress for attacks, shelters for civilians, or some combination of these? 

Before intentionally targeting such civilians, Israeli military authorities would be obligated to examine the facts and circumstances reasonably available to them at the time (and commentators should consider that such information may include information or intelligence to which the press or general public does not have access.)

    1. Direct Causation

Next, in order for a civilian to forfeit protection from direct attack, their participation in hostilities must, as the relevant treaties say, be “direct.”  As the ICRC Guidance notes, the treaty requirement that participation in hostilities be direct “implies that there can also be ‘indirect’ participation in hostilities, which does not lead to such loss of protection.”  

These indirect activities might include contributions to “the general war effort and war sustaining activities . . . that merely maintain or build up the capacity to cause . . . harm.”  Adopting a plain meaning reading of the word “direct,” the ICRC rejects any broader interpretation by embracing a position that “direct causation should be understood as meaning that the harm in question must be brought about in one causal step.”  

In other words, civilians who provide food or medical support to Hamas or the Israel Defense Forces, and even those who produce or transport weapons between storage areas would not be taking a direct part in hostilities, and therefore would not result in a loss of protection against direct attack “unless carried out as an integral part of a specific military operation designed to directly cause the required threshold of harm.”

Finally, the ICRC Guidance notes that the requirement of direct causation “refers to a degree of causal proximity, not temporal or geographic proximity.”  For example, deploying a weapon system remotely either in time (e.g., a civilian who places a pressure-triggered improvised explosive device days before its planned use) or distance (e.g., a civilian attacking an adversary with a small unmanned aerial system) would still constitute direct participation in hostilities.  

On the other hand, “although the delivery or preparation of food for combatant forces may occur in the same place and at the same time as the fighting, the causal link . . . remains indirect.”  Some commentators have sharply criticized this portion of the ICRC Guidance since, combatants who perform these critical support functions “are the same ones for which members of state armed forces can be attacked.” 

    1. Belligerent Nexus

Provided that an act exceeds the threshold of harm and is sufficiently “direct,” in order for a civilian to lose protection from direct attack the act must also have a sufficient “nexus” to the ongoing hostilities.  In other words, in order to constitute direct participation in hostilities, an act must not only be objectively likely to inflict harm, that harm must be intended to be inflicted in support of one party to an armed conflict and to the detriment of the other.  

So, for example, armed violence in Israel or Gaza “which is not designed to harm a party to an armed conflict, or which is not designed to do so in support of another party” (e.g., theft for personal gain or the murder of a personal rival) does not constitute participation in hostilities and must therefore not be addressed by the application of military force.

Duration of Loss of Protection

When civilians do directly participate in hostilities—however that may be defined—they do not lose their protection from direct attack indefinitely.  Under international law, protections remain “unless and for such time as they take a direct part in hostilities” (emphasis mine). The Supreme Court of Israel has considered this issue directly.

In Public Committee Against Torture in Israel v. Israel, the Court examined Israel’s employment of “a policy of preventative strikes which cause the death of [civilian] terrorists in Judea, Samaria, or the Gaza Strip.”  The Court noted that “regarding the scope of the wording ‘and for such time’ there is no consensus in the international literature” and offered the following guidelines for determining the lawfulness of attack:

On the one hand, a civilian taking a direct part in hostilities one single time, or sporadically, who later detaches himself from that activity, is a civilian who, starting from the time he detached himself from that activity, is entitled to protection from attack. He is not to be attacked for the hostilities which he committed in the past.  

Under this reasoning, even someone who participated in the October 7th terrorist attack, but had never previously committed such acts, vowed not to again, and was not otherwise a member of Hamas (see below) would not be subject to armed attack for his actions on October 7.  (He would of course, be subject to action by law enforcement and the applicable criminal law.)  But the court goes on:

On the other hand, a civilian who has joined a terrorist organization which has become his “home,” and in the framework of his role in that organization he commits a chain of hostilities, with short periods of rest between them, loses his immunity from attack “for such time” as he is committing the chain of acts.  Indeed, regarding such a civilian, the rest between hostilities is nothing other than preparation for the next hostility.

The ICRC Guidance adopts a narrower approach than the Supreme Court of Israel, applying its direct participation in hostilities factors (threshold of harm, direct causation, and belligerent nexus) to a definite time period limited to (1) preparatory measures leading up to the act, (2) deployment, (3) the act itself, and (4) the actor’s return.  Moreover, “preparatory measures” are limited to those acts which are “so closely linked to the subsequent execution of a specific hostile act that they already constitute an integral part of that act.”  

Here, the ICRC Guidance distinguishes between preparatory measures that aim to carry out a specific hostile act (direct participation) and preparatory measures aiming to establish the general capacity to carry out hostile acts (not direct participation).  

Examples of preparatory measures not constituting direct participation in hostilities “would commonly include purchase, production, smuggling and hiding of weapons; general recruitment and training of personnel; and financial, administrative or political support to armed actors.”

This “revolving door” of participation in hostilities is one of the most contested interpretations of the ICRC Guidance.  As one commentator put it:

“If continuous participation in hostilities has occurred, and a demonstrated intent to continue similar participation can be reasonably established, it is unreasonable to require the military to wait until that individual has begun his next attack in order to target him.  Rather, those who are continuously directly participating in hostilities are effectively members of the organized armed group who should be targetable until such time as it can be reasonably established that they have ceased functioning as such.  A goal of the law of armed conflict should be to deter direct participation in hostilities by civilians.  The ICRC approach would serve only to encourage it.”

Adopting the ICRC approach, another commentator says, “flies in the face of military common sense and accordingly represents a distortion of [international humanitarian laws’] military advantage/humanitarian considerations balance.”

However—and of significant relevance to the ongoing conflict—the ICRC Guidance describes another way that civilians might lose protection from direct attack:  membership in an organized armed group.  Determining whether a civilian is a member of an organized armed group is important since such membership may form an alternate legal basis for their loss of protection from direct attack.  

For example, an individual who was “recruited, trained and equipped” by Hamas to participate in hostilities on its behalf assumes a “continuous combat function” and therefore forfeits the protection afforded to civilians in armed conflict, even if he has not yet personally carried out a hostile act.  


Under the law of armed conflict, civilians are protected from being intentionally attacked—a universally recognized and historic legal duty of combatants.  Protecting civilians is also a moral obligation of belligerents, contributing to a lasting peace at the conclusion of an armed conflict. 

While civilians forfeit the protection of the law when they “take a direct part in hostilities,” determining whether that has happened and for what duration civilians should lose their protection requires factually and legally intensive analysis.  Application is made even more challenging by the complex environment in Israel and Gaza, requiring measured consideration of commentators and practitioners.

About the Author

Lt Col Jay Jackson serves as Senior Individual Mobilization Augmentee to the Staff Judge Advocate at the 15th Wing, Joint Base Pearl Harbor-Hickam, Hawaii.  He received a direct commission as a judge advocate in September 2006 and served on active duty until June 2020, when he transferred to the Air Force Reserve.  Lt Col Jackson’s previous assignments include tours at Joint Special Operations Command and United States Strategic Command, and he has deployed five times as the senior legal advisor of a special operations joint task force.


* The views expressed are those of the author alone and do not necessarily reflect those of any other person or entity, including the Department of the Air Force, United States Department of Defense (DoD), or the U.S. Government.  The appearance of external hyperlinks does not constitute endorsement by the DoD of the linked websites, or the information products or services contained therein.  The DoD does not exercise any editorial, security, or other control over the information you may find at these locations. 

The views expressed by guest authors do not necessarily reflect my views, those of the Center on Law, Ethics and National Security, or Duke University. See also here. 

Remember what we like to say on Lawfire®: gather the facts, examine the law, evaluate the arguments – and then decide for yourself!

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