Israel's War in Gaza and International Law

| Written By:

International law is a normative system that regulates the conduct between states, organizations recognized by international law and at times, individuals. This explainer presents an overview of international law in conflict and its application in Israel's war against Hamas.

Photo by Arie Leib Abrams/Flash90

On the morning of the joyous Simchat Torah holiday, Saturday, October 7, over a thousand terrorists infiltrated Israel from the Gaza Strip, a majority of whom were members of Hamas, with some belonging to the Palestinian Islamic Jihad organization. They infiltrated communities, perpetrated massacres on civilians – women, children, and the elderly – and seized several IDF bases. They also reached a 'Nature Party' near the border, murdering in cold blood and torturing hundreds of young people in attendance. In total, around 1,200 Israelis and foreigners, including civilians and soldiers, lost their lives in the events of October 7.

In addition, over 240 civilians and soldiers –mostly Israeli, with some international civilians—were captured alive by the terrorists, and some were killed by the terrorists. In response to all the above, the IDF mobilized hundreds of thousands of reserve soldiers and initiated a ground operation in the Gaza Strip.

The purpose of this document is to explain the international law framework within which Israel is operating in Gaza. The focus of this explanation is on the legal obligations imposed on Israel by the laws of armed conflict. In other documents, we have addressed the violations of international law committed by Hamas.

Our starting point, as stated by IDF Chief of Staff Herzi Halevy in a video published during the war, is that the IDF accepts the obligation that all its operations should be conducted according to the principles of international law.

International Law and Its Status in Israel

What is International Law?

International law is a normative system that regulates the conduct between states, organizations recognized by international law, and sometimes individuals. International law is based on the consent of states as expressed in international treaties and international customs reflecting the commonly accepted norms of the world community.

International Law in Times of War

During armed conflicts, two main branches of international law are relevant. One is "the law on the use of force," a legal branch dealing with a state's right to go to war or engage in a major armed conflict. The second is "the law of armed conflict," which deals with the rules that apply during armed conflict. It is important to emphasize that these two legal systems are independent of each other. In other words, the laws of armed conflict apply to the parties in conflict, regardless of whether the act of going to war is justified.

The Laws on the Use of Force

One of the most significant developments in international law in the last century is the imposition of limitations on the use of force. In principle, since the establishment of the United Nations, international law has adopted an absolute prohibition on the initiation of war, enshrined in Article 2(4) of the UN Charter.

There are two exceptions to this prohibition. One exception is action authorized or approved by the Security Council under Article 42 of the UN Charter. The second exception is Article 51 of the UN Charter, which states:

"Nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations, until the Security Council has taken measures necessary to maintain international peace and security."

Some argue that this article is not relevant to responding to attacks by non-state entities such as Hamas. However, Israel's position, supported by many countries worldwide, is that this article is also relevant to wars against non-state entities.

According to the accepted interpretation, the right to self-defense of a state is subject to two conditions that also limit the use of Article 51: necessity and proportionality. The meaning of necessity is clear – the use of force must be necessary, and the attack cannot be prevented in other ways, such as diplomatic means or economic sanctions. The meaning of proportionality is that the response to an armed attack must be within the necessary means to repel the attack and not exceed that. In other words, the use of force in self-defense must be commensurate with the scope, purpose, and intensity of the initial attack.

Applying this principle to the current armed conflict with Hamas, it seems clear that Israel has the right of self-defense in response to the attacks initiated by the Hamas. Furthermore, in the past sixteen years, since Hamas has taken power in the Gaza strip, Israel adopted a "containment" policy, according to which it mainly used defensive means to block Hamas attacks, including massive investments in the 'Iron Dome' missile defense system, and building an underground barrier around the Gaza strip, to block Hamas from using attack tunnels. All of these investments proved insufficient to prevent the attacks by Hamas, and a ground operation was required.

Recently, some scholars and states have raised the argument that proportionality in the law of the use of force should also account for the total harm to civilians. According to this approach, excessive harm to civilians during the entire conflict (as opposed to a specific operation) could render the use of the right to self-defense disproportionate, and hence prohibited.

This latter position does not reflect international law as it currently stands. The issue which has to be considered is whether the use of force is justified in a military operation, and not the extent of harm to civilians.

However, even if one would accept this position, in order to assess the proportionality of Israel's response, the harm to Gazan civilians should be weighed against the past 16 years of attacks, the current situation in which hundreds of thousands of Israelis are displaced in their own country, and, most importantly – the chances that such an attack would recur in the future, including considerations of the expected loss of life on both sides from future military operations if the Hamas regime is not ousted.

International Law Applicable During Armed Conflict - International Humanitarian Law

One of the oldest branches of international law is that of the laws of armed conflict, also known as "laws of war." These laws apply to both sides engaged in conflict from the moment hostilities begin, regardless of who initiated the war and whether the use of force in self-defense was justified.

This branch of international law developed along two axes: one addressing permissible methods of warfare and prohibitions on certain weapons, such as poison gas or chemical weapons. The other axis deals with the protection of groups requiring special defense during armed conflict, including wounded individuals, prisoners of war, and civilians. In recent decades, these two branches have been unified into a single system of rules regulated by a series of international conventions. Terms such as the laws of armed conflict (LOAC), laws of war, or international humanitarian law are used interchangeably.

Applicability of the laws of war

In the past decades, a significant portion of armed conflicts worldwide have involved wars between states and armed groups not recognized as states. LOAC applies to these conflicts too, albeit in a partial way: the rules regarding the protection of the civilians in armed conflict fully apply to both sides participating in all conflicts. However, rules governing issues such as the treatment of prisoners of war, and prohibitions on the use of certain weapons apply only to armed conflicts between two states.

The application of LOAC in armed conflicts between a state and a non-state actor (NSAs), such as the Taliban and Hamas, is noteworthy. Even though the laws of war are applicable to all parties in the conflict, in general, NSA's are notorious for not respecting these laws. In such cases, it is generally expected that the state will adhere to LOAC, even if the NSA does not.

Fundamental principles

LOAC are permissive in nature: a state is allowed to act in any way that is not prohibited by LOAC. LOAC do restrict the behavior of states to a certain extent, but within this framework, a state still has relatively broad discretion – much broader than during peacetime—on which means and methods of war it can use.

Below we examine several basic principles of warfare, with a focus on rules protecting non-combatant populations.

Selection of targets

Fundamental to the laws of war is the principle of distinction. According to the first additional protocol to the Geneva Conventions (which reflects customary international law):

In order to ensure respect for and protection of the civilian population and civilian objects, the Parties to the conflict shall at all times distinguish between the civilian population and combatants and between civilian objects and military objectives and accordingly shall direct their operations only against military objectives.

The purpose of this principle is to establish that attacks should be directed only against combatants, and not civilians. It is prohibited to target civilians deliberately. This fundamental rule guides the selection of targets during warfare, applying both to objects (static targets) and individuals. Regarding objects, attacks must be directed towards military objectives. Any object that serves a military purpose, even if used for both military and civilian activities, is a legitimate target (subject to the principle of proportionality, discussed below). For example, it is permissible to attack civilian structures that Hamas has converted into weapons depots if there is evidence supporting such use. Similarly, it is permissible to target a civilian structure, such as a mosque, hospital, or kindergarten, if there is evidence that it is being used for military purposes, and its destruction would provide a significant military advantage to the attacking force. However, it is not permissible to destroy targets to intimidate the civilian population.

Human targets – in principle, attacks should not be directed against the civilian population, but only towards combatants. In wars between two states, the determination of whether a target is legitimate is quite straightforward: if the target is a member of the armed forces. In an armed conflict with an NSA, the definition is more complicated. Hamas is not a state, its combatants do not distinguish themselves from the civilian population. Hence, they cannot be considered as soldiers, for example, they do not receive the status of Prisoners of War if arrested. On the other hand, it is not reasonable to grant them protection as ordinary civilians since they actively participate in warfare.

The generally accepted position in current international law is that terrorists may be considered, under certain conditions, "civilians taking a direct part in hostilities" and, therefore, individuals lacking protection. It is broadly agreed that there is no need to prove that a terrorist engaged in specific terrorist activities at the exact time of the attack, in order for them to be considered a legitimate target. Active members of Hamas who generally take part in its activities are legitimate targets.


The principle of proportionality deals with cases in which the attacking force faces a legitimate military target (a military object or combatant), but it is clear that during the attack, there is a reasonable chance (or perhaps even certainty) that civilians will be harmed. International law dictates that an attack should not be carried out if it can be anticipated that the collateral damage to civilians is excessive in relation to the concrete and direct military advantage expected.

Terrorist organizations exploit the fact that Western armies try to limit harm to civilians (often for media and public relations reasons, not necessarily legal ones). Therefore, they intentionally operate from within the civilian population, using civilians as human shields, as they assume that the attackers would be careful not to harm civilians.

This widespread use of civilians by terrorist organizations exposes the ambiguity of the proportionality principle. Firstly, the clause uses vague terminology: the expected harm to civilians should not be excessive in relation to the expected concrete military advantage. It is unclear what constitutes excessive harm to civilians and how the military advantage can be compared to civilian harm.

Secondly, how can one compare the military advantage to harm to civilians? For example, if the attacking is targeting a high-level commander, how many civilians can we consider "proportional" in terms of collateral damage? And what if the target is an arms depot?

The answers to these questions are not easy or straightforward under any circumstances, especially when a terrorist organization positions itself within a civilian population. On the one hand, a very strict interpretation of the principle of proportionality in these cases would make almost all military action impossible, as nearly every attack on a military target can put civilians in danger. On the other hand, a very lenient interpretation of the principle could cause immense harm to the civilian population.

The principle of proportionality does not guarantee the absence of harm to civilians. The principle allows the attacking military to attack a military target with the knowledge that civilians who are in close proximity to a legitimate military target might be hurt. The purpose of the principle of proportionality is to reduce harm to civilians, not to achieve parity in harm to civilians between the two sides. The attacking military is committed to assessing the extent of harm to civilians, trying to minimize it, and in some cases, even refraining from an attack if the expected harm to civilians is excessive. The principle of proportionality does not promise, and no legal principle can promise, war without harm to civilians.

The principle of proportionality, therefore, is a guiding principle and not an exact mathematical formula. The fact that abundant information can be obtained through modern technological means imposes on the army the duty to obtain this information and use it to reduce harm to civilians.

The Principle of Proportionality and the Defense of Soldiers' Lives

The principle of proportionality is not only relevant to attacks from the air or from a distance. This principle is also relevant to close-range battles, especially in battles in populous areas where a civilian population is present. Commanders may face situations where they must choose, operationally, between the risk to the lives of soldiers and the risk to the lives of civilians.

The accepted answer in international law to this question is also embedded in the principle of proportionality. Preserving the lives of soldiers is a legitimate military interest of any army, including the IDF. Israel is entitled to prioritize this interest, as long as it is not expected to lead to disproportionate harm to the lives of uninvolved Palestinian civilians.

Precautions in attack: Warnings Before Attack and Evacuation of Civilians

The attacking army has an obligation to use precaution in attack, for example, to provide a warning before an attack, as far as military circumstances allow. The warning or alert can be given through any method proven to be effective.

Several important points should be noted about warnings in the context of the war against Hamas:

Firstly, the central duty for evacuating the Palestinian population from the combat zones lies with Hamas. The fact that Hamas refrains from doing so and often acts to force the civilian population to remain in the combat zone may constitute a war crime by itself.

Secondly, the fact that advance warning has been given to a specific area does not permit the attacking army to conclude that, from the moment the warning is given, it is exempt from considering the civilian population. It is prohibited to declare that residents who remained in the area after the warning was given have forfeited their inherent protection as civilians, whether they stayed voluntarily, due to inability to evacuate due to illness or old age, or if they were forced to stay by Hamas.

Lastly, the duty of warning does not apply in situations where "the circumstances do not permit it." This clause is mainly intended to protect a state's ability to surprise the enemy forces and to take a type of action where warning is impossible.

Specific Issues in The Present War

Evacuation of the City of Gaza

Israel acted according to its duty, warning the residents of Gaza City to evacuate, as Israel was about to attack the city. Temporary evacuation of residents through effective warnings is considered legal, subject to a pressing military need. In practice, the evacuation of civilians is often a logical outcome of providing an effective warning, prompting residents to leave the combat area. However, not all civilian evacuation is legal. Historically, the evacuation of civilian populations from combat areas has often become a humanitarian disaster, leading to their permanent expulsion from their homes. Therefore, international law includes several conditions for the execution of civilian evacuation.

The Legal Conditions for Evacuating Populations in Wartime:

To ensure that evacuation is not considered forced displacement but indeed evacuation, Israel had to adhere to the following obligations:

(1)  Evacuation must be temporary during wartime and intended to protect residents from the war. There must be no intention to permanently relocate the residents.

 (2) Humanitarian corridors must be defined, allowing movement to protected areas, with sufficient time provided to reach them.

 (3) Evacuation must be to places where there is assurance that residents will be protected from attack.

 (4)  Basic humanitarian assistance must be provided in evacuated areas: food, water, electricity, adequate hygiene conditions, and basic medical supplies.

Israel faced considerable criticism at the beginning of the war, especially regarding whether sufficient time was given to reach protected areas and compliance with humanitarian principles. However, it seems that with the onset of hostilities, Israel did comply with its obligations.

Evacuation of Hospitals – Particularly Shifa Hospital:

The principle of distinction described earlier applies to the sick and wounded during wartime, whether civilians or soldiers. This protection includes medical teams and medical institutions such as ambulances and hospitals. However, this special protection applies only as long as the hospital or ambulance is not used for military purposes that would give the enemy a significant military advantage. If a medical institution loses its protection, a warning should be given before any attack.

The events at Shifa Hospital during this war involved the institution losing its protection due to evidence of its use as a military base, for storage of weapons, and possibly for housing Israeli captives. Even after notifying the hospital of its loss of protected status and an impending attack, Israel limited its military action near and inside Shifa Hospital while trying to provide support for patients, wounded individuals, and medical teams who remained in the hospital.

During the attack, many warnings were received from hospital officials that the hospital lacks basic medical equipment and electricity supply, such that the lives of the patients are endangered. In accordance with these warnings, the IDF Spokesperson announced that Israel had transferred 300 liters of diesel fuel to the hospital, but that Hamas was preventing the collection of the fuel. Subsequently, the IDF initiated a coordinated humanitarian effort to transfer incubators and additional medical equipment to the hospital.

Humanitarian Supplies to the Gaza Strip:

According to Article 24 of the Fourth Geneva Convention, states engaging in armed conflict are obligated to allow the free passage of medical supplies, food, and equipment for children and pregnant women. Passage must be allowed as long as there is no reasonable suspicion that the supplies are intended for military advantage or diversion for military use.

Additionally, there is an absolute prohibition on starving the civilian population as a method of warfare. It should be clarified that the prohibition on starvation does not include the imposition of a siege, as long as the purpose of the siege is to achieve a military objective against enemy forces and not to starve the civilian population.


Israel's actions during the war adhere to the principles of international law governing armed conflict. This article aimed to outline some of the fundamental matters applicable during this operation.

It is important to note that Israel's adherence to international law during military operations is motivated by several factors. Firstly, Israel is committed to upholding the law, and part of its democratic strength lies in dealing with adversaries while maintaining legal and moral standards. The fact that one can misuse international law for malicious purposes does not negate the overall legitimacy of international law. Secondly, during times of conflict, Israel needs international support. While certain countries may not support Israel under any circumstances, others, particularly those crucial to Israel's policy, base their stance on Israel's adherence to international legal principles.

Watch Prof. Amichai Cohen explain the principles of International law and the rules of war, as they apply to Israel in the Israel-Hamas war: