Introduction
Siege is one of the oldest and most complex methods of warfare. Armies have used it for millennia to surround cities, isolate defending forces, cut off their supplies, and force surrender or secure tactical advantage. In the modern era, with the rise of international humanitarian law and advances in military technology, siege has become a source of legal, operational, and moral debate. In Israel, the issue resurfaced at the end of 2024 in the run-up to the large-scale operation in Jabalia and the discussion of the “Generals’ Plan,” and again with the emerging plan for the conquest of the Gaza Strip.
The Military Advocate General and the Attorney General, as quoted in various discussions, have opposed the use of siege, arguing that it contravenes international law.[1] Yet no written opinion has been issued—perhaps because of the difficulty of justifying such a position under international law, particularly when many international experts regard siege as a lawful and legitimate instrument.
However, no written opinion has been published, perhaps due to the difficulty of justifying it under international law, particularly when many international experts regard siege as a lawful and legitimate instrument.
This article examines siege from legal and operational perspectives. We argue that siege is a lawful method, firmly grounded in the laws of war and constituting an accepted practice by Western militaries, as evidenced in U.S. Army field manuals, West Point’s military doctrine, and in British manuals. We stress that siege, when making sure to allow the evacuation of civilians, does not harm the civilian population, since civilians can leave the combat zone at any time. Siege also reduces risks to our forces, weakens the enemy, and gives enemy fighters an opportunity to surrender. We will examine international law—including the Geneva and Hague Conventions, commentary by the International Committee of the Red Cross (ICRC), and British and American military manuals—alongside the IDF’s operational experience in Gaza. Finally, we will consider the implications of restrictive legal opinions for military operations and the increased risks they create for our forces.
The History of Siege as a Method of Warfare
Siege is an ancient military practice, rooted in early civilizations in the Middle East, China, Greece, and Rome. Fortified cities such as Jericho, Troy, and Carthage forced attackers to surround them, block food, water, and supplies, and compel surrender or destruction of defenders. In the Middle Ages, siege evolved into a sophisticated art, with the use of catapults, siege towers, and tunnels running under fortifications. With the development of artillery in the fifteenth century, city walls became a less effective defense, but siege remained a relevant means of securing control over territory.
In modern history, siege has often been accompanied by severe humanitarian consequences. During World War II, the German siege of Leningrad (1941–1944) caused the deaths of roughly a million civilians through starvation, cold, and bombardment. More recently, sieges became central features of urban warfare: Sarajevo in Bosnia (1992–1996), Mosul in Iraq (2016–2017), and Aleppo in Syria (2016).
The IDF too has employed siege. During Israel’s War of Independence, the four-month siege of the Faluja pocket served as leverage to push Egypt toward signing the armistice agreement. In the Yom Kippur War, the siege of the Egyptian Third Army likewise pressured Egypt to agree to a ceasefire and facilitated the return of all Israeli prisoners of war (an example that is extremely relevant in view of the hostage crisis). In the First Lebanon War, the siege of Beirut ended with the expulsion of PLO forces, led by Yasser Arafat, to Tunisia.
The Legal Dimension
International humanitarian law regulates the use of siege, balancing military necessity against the protection of civilians. The legal framework rests on the Hague and Geneva Conventions and their additional protocols.
The 1907 Hague Convention is a cornerstone of the laws of war. Regulation 25 states: “The attack or bombardment, by whatever means, of towns, villages, dwellings, or buildings which are undefended is prohibited.” Yet Regulation 27 clarifies: “In sieges and bombardments all necessary steps must be taken to spare, as far as possible, buildings dedicated to religion, art, science, or charitable purposes, historic monuments, hospitals, and places where the sick and wounded are collected, provided they are not being used at the time for military purposes.” This makes clear that siege is lawful when militarily necessary, so long as steps are taken to protect civilians and protected sites.[2]
The Fourth Geneva Convention (1949) protecting civilians in time of war includes provisions relevant to siege. Article 17 states: “The Parties to the conflict shall endeavour to conclude local agreements for the removal from besieged or encircled areas, of wounded, sick, infirm, and aged persons, children and maternity cases, and for the passage of ministers of all religions, medical personnel and medical equipment on their way to such areas.” Article 23 requires the warring parties to allow humanitarian relief such as food and medicine, unless there is a concrete risk it will reach enemy forces. Additional Protocol I (1977) Article 54(1) adds: “Starvation of civilians as a method of warfare is prohibited.” This clause, however, allows siege when its aim is military and not the deliberate starvation of civilians.
Additional Protocol II (for non-international conflicts) Article 14 reinforces this prohibition. Rule 53 of customary international humanitarian law, as defined by the ICRC, similarly states: “The use of starvation of the civilian population as a method of warfare is prohibited.” This rule emphasizes that siege must be accompanied by measures to protect civilians, including evacuation and the provision of aid.
International tribunals have not banned siege outright but have clarified its limits. The International Criminal Tribunal for the former Yugoslavia judgment in the case of Stansislav Galic (2003) ruled that deliberately targeting civilians during the Sarajevo siege was a war crime, but the siege itself was not unlawful so long as it targeted enemy forces. Likewise, a UN report on Yemen concluded that siege must comply with proportionality—namely that civilian harm must not outweigh anticipated military advantage.[3]
The ICRC notes that siege is not prohibited per se, provided it is not intended to starve civilians, and that the passage of neutral humanitarian relief must be allowed.[4] Moreover, the parties must afford protection to civilians, allow them safe evacuation, and not employ them as human shields. Where the besieged party—such as Hamas—blocks civilians from leaving, it violates international law and is guilty of using them as human shields. In such cases, the principle of proportionality still applies to any civilian harm.[5]
Liron Libman, former Military Advocate General and head of the IDF’s International Law Department, and later a research fellow in the Law and Security Program at the Israel Democracy Institute, has argued that “siege is a lawful method of warfare under international law, so long as its purpose is to bring about the surrender of the enemy in the encircled area by denying supplies of every kind, including food and water, to enemy fighters, and not to starve civilians in the besieged area. To this end, humanitarian aid must either be allowed in for civilians or, alternatively, civilians must be permitted to leave the besieged area safely for a place where they can receive the humanitarian assistance necessary for their survival.”[6]
The U.S. military also recognizes siege as a legitimate tool within legal constraints. The Department of Defense Law of War Manual [7]states that starvation of civilians as a method of warfare is prohibited, but siege is permitted when its purpose is to weaken enemy forces and civilian harm is not excessive. It stresses that sieges must allow civilian evacuation and humanitarian access in line with the Geneva Conventions.
At the West Point military academy, siege is taught as part of urban warfare doctrine. As Professor Sean Watts of West Point’s Department of Law has put it, “Current U.S. operational doctrine speaks of physical, psychological, and most recently electronic isolation. Each form of isolation is essential to achieving the enemy attrition that in assaults is achieved by direct attack. Simply put, isolation is paramount to effective siege.”[8] West Point doctrine emphasizes that siege can reduce the need for direct combat and thus lower risks to one’s own forces. The U.S. Army’s urban warfare field manual [9]views siege as a strategy for avoiding street-by-street fighting, stressing the principles of distinction and proportionality and requiring careful planning, including humanitarian corridors for evacuation.
The British manual of the law of armed conflict also affirms the legitimacy of siege, stating that forces may cut off an enemy-held area from supplies and communication, provided civilians are allowed to leave. In cases where the enemy prevents or attempts to prevent civilians from leaving the area, the British manual notes that so long as civilians are in fact able to leave, blocking the entry of aid into the besieged area is justified.[10]
Taken together, these sources establish that siege is lawful when its purpose is to defeat the enemy and achieve military objectives, provided civilians can leave through humanitarian corridors and access aid outside the besieged zone. In this context, it is the military commander alone who determines compliance with the principle of proportionality.[11]
Operational Analysis: The Advantages of Siege and the Israeli Experience
From an operational perspective, siege offers major advantages. First, it isolates the enemy, denies him food, fuel, ammunition, and reinforcements, and weakens him without direct combat. Second, it reduces risks to one’s own forces by avoiding face-to-face fighting in dense urban terrain, where defenders often hold the advantage. Thus, siege enables control of territory without entering narrow killing zones where the enemy can employ traps, snipers, or explosive devices. Third, siege gives the enemy the option to surrender, thereby reducing the need for widespread destruction or mass casualties. By cutting off supplies, siege weakens the enemy and increases the likelihood that he will choose to capitulate.
Siege tactics include dividing an area under siege into isolated sectors, using precision fire, and applying psychological pressure with leaflets, broadcasts, or social media to warn civilians and encourage surrender or evacuation. Siege may also involve cutting communications and blocking internet access to prevent the enemy from coordinating his forces.
In the case of Gaza, siege can be especially effective given the geography of Gaza City: a small, densely populated area bounded by land and sea. When combined with civilian evacuation, siege will enable the IDF to focus on Hamas fighters while minimizing harm to civilians.
The IDF has gained extensive experience in evacuating civilians from combat zones in Gaza, proving that siege with evacuation is both practical and effective. In October 2023, about a million people were evacuated from northern Gaza and Gaza City to the south as ground operations began. In January 2024, 300,000–400,000 people were evacuated from Khan Yunis to al-Mawasi and Rafah as the fighting progressed. In May 2024, 1.4 million people left Rafah and headed north as the city was taken. In January 2025, after a ceasefire reached in the framework of the second hostage deal and the IDF’s withdrawal from the Netzarim Corridor, hundreds of thousands of residents returned to northern Gaza within days.
In addition to these mass evacuations, the IDF has carried out dozens of smaller-scale evacuations tied to troop advances or strikes on Hamas targets. These demonstrate that civilian evacuation is a structured, professional, and effective practice, adapted to the realities of combat.
Urban warfare in environments such as Gaza is further complicated by the enemy’s frequent use of civilians as human shields. Hamas fighters hide in schools, hospitals, clinics, and mosques, making it difficult for IDF forces to operate without endangering civilians. Examples include the use of Shifa Hospital to hide hostages, terrorists, and weapons, and tunnels linking the hospital to Hamas’s command network; the ongoing use of al-Aqsa Hospital in Deir al-Balah as a command post and operations center; and the presence of Yahya Sinwar and Mohammed Deif, who were killed in a civilian tent compound in al-Mawasi, as well as Mohammed Sinwar and Mohammed Shabana, who hid beneath the European Hospital in Khan Yunis.
The Legal Opinions of the IDF and the Attorney General
The opposition of the Military Advocate General and the Attorney General to siege has been criticized for lacking clear legal foundation.[12] The absence of any published written opinion suggests difficulty in defending such a stance under international law, which recognizes siege as lawful when civilians are protected.
Past clashes between legal advisors and commanders highlight this tension. During the violent Gaza border protests of 2017–2018, fearing mass breaches, then–IDF Chief of Staff Gadi Eisenkot authorized live fire against individuals approaching the barrier and endangering troops. Then–Military Advocate General Sharon Afek argued the order was unlawful. Eisenkot responded that responsibility lay with him as commander, that the order was valid and legal, and that Afek was free to petition the High Court of Justice. The decision underscored command responsibility and the need to weigh operational, legal, and ethical considerations.
In another case, during the initial stages of the Gaza war, the IDF developed an air-dropped system for neutralizing explosives. The Military Advocate General deemed it unlawful, and then–Chief of Staff Herzi Halevi accepted that view, canceling its use despite increased risk to soldiers.
These cases highlight the need to reconsider the role of legal opinions in military operations. Final decisions must rest with commanders, who weigh all the relevant considerations, including the risks to forces and the need to complete the military mission. Legal advice is just that—advice. It should not become binding when it unnecessarily constrains operations without clear justification.
The personnel composition of the Military Advocate General’s Corps also raises questions about its suitability to take decisions relating to a combat environment. Most of its officers come up through the legal system without combat experience or deep familiarity with battlefield realities. This lack of relevant experience may lead to opinions that fail to sufficiently account for operational complexity, thereby endangering forces.
Past efforts to integrate field commanders with combat backgrounds into the corps have faltered, but such integration is critical—especially in areas like siege or innovative weapons, where a legal opinion on operational matters is required. A legal officer with combat experience is better placed to balance military and legal considerations and provide recommendations suited to a complex combat environment.
The Chief of Staff and his commanders carry immense responsibility—for Israel’s security, the mission, the lives of their troops, and the army’s ethical standards. Leadership requires decision-making in conditions of uncertainty while weighing all the elements under a commander’s responsibility. No one can replace the commander in making those decisions. Professional advice—from intelligence, logistics, or legal experts—is important and should be sought, but the responsibility and the decision ultimately rest with the commander.
When considering a siege on Gaza City, commanders must weigh all elements. Based on the past two years of experience, it is reasonable to argue that evacuating civilians for their protection and then imposing a siege would produce better operational results, in less time, with lower risk to our forces and reduced harm to civilians.
As for international legitimacy, two points stand out. First, Israel must be prepared to bear some loss of legitimacy if the outcome is faster mission success, reduced risk to our soldiers, and less civilian harm. Second, accusations of starvation and siege are already leveled against Israel—even before any siege has begun—even as Israel continues to let in food and aid that ends up in Hamas’s hands. It is better to win decisively, even if the cost is diminished affection abroad.
Conclusion
Siege is a lawful and legitimate method of warfare, anchored in international law and Western military practice. In Gaza, when combined with civilian evacuation and prior warnings, it enables the IDF to gain military advantage while minimizing harm to civilians. Israeli experience shows that civilian evacuation is feasible and effective, and siege can significantly reduce risks to our forces and to civilians.
The opposition of the Military Advocate General to siege raises doubts about its legal basis. The issue must be brought to the forefront, the legality of siege examined, and the role of legal opinions within the military reassessed. Reform of the Military Advocate General’s Corps is needed, including the integration of field commanders with combat experience into the Corps so as to ensure legal opinions reflect operational reality. Ultimately, legal advice is just that—advice. The Chief of Staff bears final responsibility for decisions.
Given the above, the IDF should take the following steps in the initial stage of operations in Gaza City: (1) Announce that civilians must evacuate for their own safety, particularly given the expected intensification of combat. Evacuation routes should ensure safe passage under IDF protection. (2) Establish distribution points south of the Netzarim Corridor for food and medical aid, so evacuees can receive humanitarian assistance in line with the norms of international law. (3) Halt all supplies—including food and water—into the combat zone, thereby imposing an effective siege on Gaza City. (4) Intensify combat operations in Gaza City until Hamas is defeated.
When carried out in accordance with international law, siege is a vital means of securing military victory while protecting the lives of soldiers and civilians. Israel, which is engaged in combat in an extraordinarily complex environment, should adopt a balanced approach that integrates legal and operational considerations while placing ultimate responsibility in the hands of field commanders.
[1] Amir Ettinger, “Netanyahu and Ministers Demanded Changes to the Humanitarian Aid Plan, IDF Chief of Staff: The IDF’s Legal Position Does Not Allow It,” (Hebrew) Israel Hayom, May 15, 2025.
[2] In the context of Gaza, it should be noted that almost all of the supposedly protected facilities—hospitals, clinics, mosques, and schools—have been used for terrorist purposes, thereby losing their protected status.
[3] Human Rights Council Forty-fifth session 14 September – 2 October 2020, Human Rights Council, Forty-fifth session, 14 September–2 October 2020
[4] The protection of the civilian population during sieges: what the law says, International Committee of the Red Cross, 2024
[5] John Spencer, Urban Warfare Project Podcast: Siege Warfare and Civilian Evacuations, 28 February 2025
[6] Col. (res.) Dr. Liron A. Libman, Legal Opinion on the Proposed Alternative Strategy, November 7, 2024 (Hebrew)
[7] Department of Defense, Law of War Manual, Office of General Counsel, 2015
[8] Sean Watts, Siege Law, West Point, March 4, 2022
[9] FM 3-06, Urban Operations, 2017, Headquarters, Department of the Army, 2006
[10] UK, THE JOINT SERVICE MANUAL OF THE LAW OF ARMED CONFLICT, 5.34.1 (2004)
[11] The principle of proportionality in international law permits attacks expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or any combination of the above. Commanders must, however, weigh expected harm against the concrete and direct military advantage anticipated from the attack. See International Expert Meeting Report: The Principle of Proportionality, International Committee of the Red Cross, September 3, 2018.
[12] Amir Ettinger, “After the Dispute over Humanitarian Aid: Call for an Urgent Meeting of the Foreign Affairs and Defense Committee” (Hebrew), Israel Hayom, May 15, 2025.
JISS Policy Papers are published through the generosity of the Greg Rosshandler Family.
Home page / Articles / Siege as a Legitimate Method of Warfare
Siege as a Legitimate Method of Warfare
Photo: Shutterstock
Introduction
Siege is one of the oldest and most complex methods of warfare. Armies have used it for millennia to surround cities, isolate defending forces, cut off their supplies, and force surrender or secure tactical advantage. In the modern era, with the rise of international humanitarian law and advances in military technology, siege has become a source of legal, operational, and moral debate. In Israel, the issue resurfaced at the end of 2024 in the run-up to the large-scale operation in Jabalia and the discussion of the “Generals’ Plan,” and again with the emerging plan for the conquest of the Gaza Strip.
The Military Advocate General and the Attorney General, as quoted in various discussions, have opposed the use of siege, arguing that it contravenes international law.[1] Yet no written opinion has been issued—perhaps because of the difficulty of justifying such a position under international law, particularly when many international experts regard siege as a lawful and legitimate instrument.
However, no written opinion has been published, perhaps due to the difficulty of justifying it under international law, particularly when many international experts regard siege as a lawful and legitimate instrument.
This article examines siege from legal and operational perspectives. We argue that siege is a lawful method, firmly grounded in the laws of war and constituting an accepted practice by Western militaries, as evidenced in U.S. Army field manuals, West Point’s military doctrine, and in British manuals. We stress that siege, when making sure to allow the evacuation of civilians, does not harm the civilian population, since civilians can leave the combat zone at any time. Siege also reduces risks to our forces, weakens the enemy, and gives enemy fighters an opportunity to surrender. We will examine international law—including the Geneva and Hague Conventions, commentary by the International Committee of the Red Cross (ICRC), and British and American military manuals—alongside the IDF’s operational experience in Gaza. Finally, we will consider the implications of restrictive legal opinions for military operations and the increased risks they create for our forces.
The History of Siege as a Method of Warfare
Siege is an ancient military practice, rooted in early civilizations in the Middle East, China, Greece, and Rome. Fortified cities such as Jericho, Troy, and Carthage forced attackers to surround them, block food, water, and supplies, and compel surrender or destruction of defenders. In the Middle Ages, siege evolved into a sophisticated art, with the use of catapults, siege towers, and tunnels running under fortifications. With the development of artillery in the fifteenth century, city walls became a less effective defense, but siege remained a relevant means of securing control over territory.
In modern history, siege has often been accompanied by severe humanitarian consequences. During World War II, the German siege of Leningrad (1941–1944) caused the deaths of roughly a million civilians through starvation, cold, and bombardment. More recently, sieges became central features of urban warfare: Sarajevo in Bosnia (1992–1996), Mosul in Iraq (2016–2017), and Aleppo in Syria (2016).
The IDF too has employed siege. During Israel’s War of Independence, the four-month siege of the Faluja pocket served as leverage to push Egypt toward signing the armistice agreement. In the Yom Kippur War, the siege of the Egyptian Third Army likewise pressured Egypt to agree to a ceasefire and facilitated the return of all Israeli prisoners of war (an example that is extremely relevant in view of the hostage crisis). In the First Lebanon War, the siege of Beirut ended with the expulsion of PLO forces, led by Yasser Arafat, to Tunisia.
The Legal Dimension
International humanitarian law regulates the use of siege, balancing military necessity against the protection of civilians. The legal framework rests on the Hague and Geneva Conventions and their additional protocols.
The 1907 Hague Convention is a cornerstone of the laws of war. Regulation 25 states: “The attack or bombardment, by whatever means, of towns, villages, dwellings, or buildings which are undefended is prohibited.” Yet Regulation 27 clarifies: “In sieges and bombardments all necessary steps must be taken to spare, as far as possible, buildings dedicated to religion, art, science, or charitable purposes, historic monuments, hospitals, and places where the sick and wounded are collected, provided they are not being used at the time for military purposes.” This makes clear that siege is lawful when militarily necessary, so long as steps are taken to protect civilians and protected sites.[2]
The Fourth Geneva Convention (1949) protecting civilians in time of war includes provisions relevant to siege. Article 17 states: “The Parties to the conflict shall endeavour to conclude local agreements for the removal from besieged or encircled areas, of wounded, sick, infirm, and aged persons, children and maternity cases, and for the passage of ministers of all religions, medical personnel and medical equipment on their way to such areas.” Article 23 requires the warring parties to allow humanitarian relief such as food and medicine, unless there is a concrete risk it will reach enemy forces. Additional Protocol I (1977) Article 54(1) adds: “Starvation of civilians as a method of warfare is prohibited.” This clause, however, allows siege when its aim is military and not the deliberate starvation of civilians.
Additional Protocol II (for non-international conflicts) Article 14 reinforces this prohibition. Rule 53 of customary international humanitarian law, as defined by the ICRC, similarly states: “The use of starvation of the civilian population as a method of warfare is prohibited.” This rule emphasizes that siege must be accompanied by measures to protect civilians, including evacuation and the provision of aid.
International tribunals have not banned siege outright but have clarified its limits. The International Criminal Tribunal for the former Yugoslavia judgment in the case of Stansislav Galic (2003) ruled that deliberately targeting civilians during the Sarajevo siege was a war crime, but the siege itself was not unlawful so long as it targeted enemy forces. Likewise, a UN report on Yemen concluded that siege must comply with proportionality—namely that civilian harm must not outweigh anticipated military advantage.[3]
The ICRC notes that siege is not prohibited per se, provided it is not intended to starve civilians, and that the passage of neutral humanitarian relief must be allowed.[4] Moreover, the parties must afford protection to civilians, allow them safe evacuation, and not employ them as human shields. Where the besieged party—such as Hamas—blocks civilians from leaving, it violates international law and is guilty of using them as human shields. In such cases, the principle of proportionality still applies to any civilian harm.[5]
Liron Libman, former Military Advocate General and head of the IDF’s International Law Department, and later a research fellow in the Law and Security Program at the Israel Democracy Institute, has argued that “siege is a lawful method of warfare under international law, so long as its purpose is to bring about the surrender of the enemy in the encircled area by denying supplies of every kind, including food and water, to enemy fighters, and not to starve civilians in the besieged area. To this end, humanitarian aid must either be allowed in for civilians or, alternatively, civilians must be permitted to leave the besieged area safely for a place where they can receive the humanitarian assistance necessary for their survival.”[6]
The U.S. military also recognizes siege as a legitimate tool within legal constraints. The Department of Defense Law of War Manual [7]states that starvation of civilians as a method of warfare is prohibited, but siege is permitted when its purpose is to weaken enemy forces and civilian harm is not excessive. It stresses that sieges must allow civilian evacuation and humanitarian access in line with the Geneva Conventions.
At the West Point military academy, siege is taught as part of urban warfare doctrine. As Professor Sean Watts of West Point’s Department of Law has put it, “Current U.S. operational doctrine speaks of physical, psychological, and most recently electronic isolation. Each form of isolation is essential to achieving the enemy attrition that in assaults is achieved by direct attack. Simply put, isolation is paramount to effective siege.”[8] West Point doctrine emphasizes that siege can reduce the need for direct combat and thus lower risks to one’s own forces. The U.S. Army’s urban warfare field manual [9]views siege as a strategy for avoiding street-by-street fighting, stressing the principles of distinction and proportionality and requiring careful planning, including humanitarian corridors for evacuation.
The British manual of the law of armed conflict also affirms the legitimacy of siege, stating that forces may cut off an enemy-held area from supplies and communication, provided civilians are allowed to leave. In cases where the enemy prevents or attempts to prevent civilians from leaving the area, the British manual notes that so long as civilians are in fact able to leave, blocking the entry of aid into the besieged area is justified.[10]
Taken together, these sources establish that siege is lawful when its purpose is to defeat the enemy and achieve military objectives, provided civilians can leave through humanitarian corridors and access aid outside the besieged zone. In this context, it is the military commander alone who determines compliance with the principle of proportionality.[11]
Operational Analysis: The Advantages of Siege and the Israeli Experience
From an operational perspective, siege offers major advantages. First, it isolates the enemy, denies him food, fuel, ammunition, and reinforcements, and weakens him without direct combat. Second, it reduces risks to one’s own forces by avoiding face-to-face fighting in dense urban terrain, where defenders often hold the advantage. Thus, siege enables control of territory without entering narrow killing zones where the enemy can employ traps, snipers, or explosive devices. Third, siege gives the enemy the option to surrender, thereby reducing the need for widespread destruction or mass casualties. By cutting off supplies, siege weakens the enemy and increases the likelihood that he will choose to capitulate.
Siege tactics include dividing an area under siege into isolated sectors, using precision fire, and applying psychological pressure with leaflets, broadcasts, or social media to warn civilians and encourage surrender or evacuation. Siege may also involve cutting communications and blocking internet access to prevent the enemy from coordinating his forces.
In the case of Gaza, siege can be especially effective given the geography of Gaza City: a small, densely populated area bounded by land and sea. When combined with civilian evacuation, siege will enable the IDF to focus on Hamas fighters while minimizing harm to civilians.
The IDF has gained extensive experience in evacuating civilians from combat zones in Gaza, proving that siege with evacuation is both practical and effective. In October 2023, about a million people were evacuated from northern Gaza and Gaza City to the south as ground operations began. In January 2024, 300,000–400,000 people were evacuated from Khan Yunis to al-Mawasi and Rafah as the fighting progressed. In May 2024, 1.4 million people left Rafah and headed north as the city was taken. In January 2025, after a ceasefire reached in the framework of the second hostage deal and the IDF’s withdrawal from the Netzarim Corridor, hundreds of thousands of residents returned to northern Gaza within days.
In addition to these mass evacuations, the IDF has carried out dozens of smaller-scale evacuations tied to troop advances or strikes on Hamas targets. These demonstrate that civilian evacuation is a structured, professional, and effective practice, adapted to the realities of combat.
Urban warfare in environments such as Gaza is further complicated by the enemy’s frequent use of civilians as human shields. Hamas fighters hide in schools, hospitals, clinics, and mosques, making it difficult for IDF forces to operate without endangering civilians. Examples include the use of Shifa Hospital to hide hostages, terrorists, and weapons, and tunnels linking the hospital to Hamas’s command network; the ongoing use of al-Aqsa Hospital in Deir al-Balah as a command post and operations center; and the presence of Yahya Sinwar and Mohammed Deif, who were killed in a civilian tent compound in al-Mawasi, as well as Mohammed Sinwar and Mohammed Shabana, who hid beneath the European Hospital in Khan Yunis.
The Legal Opinions of the IDF and the Attorney General
The opposition of the Military Advocate General and the Attorney General to siege has been criticized for lacking clear legal foundation.[12] The absence of any published written opinion suggests difficulty in defending such a stance under international law, which recognizes siege as lawful when civilians are protected.
Past clashes between legal advisors and commanders highlight this tension. During the violent Gaza border protests of 2017–2018, fearing mass breaches, then–IDF Chief of Staff Gadi Eisenkot authorized live fire against individuals approaching the barrier and endangering troops. Then–Military Advocate General Sharon Afek argued the order was unlawful. Eisenkot responded that responsibility lay with him as commander, that the order was valid and legal, and that Afek was free to petition the High Court of Justice. The decision underscored command responsibility and the need to weigh operational, legal, and ethical considerations.
In another case, during the initial stages of the Gaza war, the IDF developed an air-dropped system for neutralizing explosives. The Military Advocate General deemed it unlawful, and then–Chief of Staff Herzi Halevi accepted that view, canceling its use despite increased risk to soldiers.
These cases highlight the need to reconsider the role of legal opinions in military operations. Final decisions must rest with commanders, who weigh all the relevant considerations, including the risks to forces and the need to complete the military mission. Legal advice is just that—advice. It should not become binding when it unnecessarily constrains operations without clear justification.
The personnel composition of the Military Advocate General’s Corps also raises questions about its suitability to take decisions relating to a combat environment. Most of its officers come up through the legal system without combat experience or deep familiarity with battlefield realities. This lack of relevant experience may lead to opinions that fail to sufficiently account for operational complexity, thereby endangering forces.
Past efforts to integrate field commanders with combat backgrounds into the corps have faltered, but such integration is critical—especially in areas like siege or innovative weapons, where a legal opinion on operational matters is required. A legal officer with combat experience is better placed to balance military and legal considerations and provide recommendations suited to a complex combat environment.
The Chief of Staff and his commanders carry immense responsibility—for Israel’s security, the mission, the lives of their troops, and the army’s ethical standards. Leadership requires decision-making in conditions of uncertainty while weighing all the elements under a commander’s responsibility. No one can replace the commander in making those decisions. Professional advice—from intelligence, logistics, or legal experts—is important and should be sought, but the responsibility and the decision ultimately rest with the commander.
When considering a siege on Gaza City, commanders must weigh all elements. Based on the past two years of experience, it is reasonable to argue that evacuating civilians for their protection and then imposing a siege would produce better operational results, in less time, with lower risk to our forces and reduced harm to civilians.
As for international legitimacy, two points stand out. First, Israel must be prepared to bear some loss of legitimacy if the outcome is faster mission success, reduced risk to our soldiers, and less civilian harm. Second, accusations of starvation and siege are already leveled against Israel—even before any siege has begun—even as Israel continues to let in food and aid that ends up in Hamas’s hands. It is better to win decisively, even if the cost is diminished affection abroad.
Conclusion
Siege is a lawful and legitimate method of warfare, anchored in international law and Western military practice. In Gaza, when combined with civilian evacuation and prior warnings, it enables the IDF to gain military advantage while minimizing harm to civilians. Israeli experience shows that civilian evacuation is feasible and effective, and siege can significantly reduce risks to our forces and to civilians.
The opposition of the Military Advocate General to siege raises doubts about its legal basis. The issue must be brought to the forefront, the legality of siege examined, and the role of legal opinions within the military reassessed. Reform of the Military Advocate General’s Corps is needed, including the integration of field commanders with combat experience into the Corps so as to ensure legal opinions reflect operational reality. Ultimately, legal advice is just that—advice. The Chief of Staff bears final responsibility for decisions.
Given the above, the IDF should take the following steps in the initial stage of operations in Gaza City: (1) Announce that civilians must evacuate for their own safety, particularly given the expected intensification of combat. Evacuation routes should ensure safe passage under IDF protection. (2) Establish distribution points south of the Netzarim Corridor for food and medical aid, so evacuees can receive humanitarian assistance in line with the norms of international law. (3) Halt all supplies—including food and water—into the combat zone, thereby imposing an effective siege on Gaza City. (4) Intensify combat operations in Gaza City until Hamas is defeated.
When carried out in accordance with international law, siege is a vital means of securing military victory while protecting the lives of soldiers and civilians. Israel, which is engaged in combat in an extraordinarily complex environment, should adopt a balanced approach that integrates legal and operational considerations while placing ultimate responsibility in the hands of field commanders.
[1] Amir Ettinger, “Netanyahu and Ministers Demanded Changes to the Humanitarian Aid Plan, IDF Chief of Staff: The IDF’s Legal Position Does Not Allow It,” (Hebrew) Israel Hayom, May 15, 2025.
[2] In the context of Gaza, it should be noted that almost all of the supposedly protected facilities—hospitals, clinics, mosques, and schools—have been used for terrorist purposes, thereby losing their protected status.
[3] Human Rights Council Forty-fifth session 14 September – 2 October 2020, Human Rights Council, Forty-fifth session, 14 September–2 October 2020
[4] The protection of the civilian population during sieges: what the law says, International Committee of the Red Cross, 2024
[5] John Spencer, Urban Warfare Project Podcast: Siege Warfare and Civilian Evacuations, 28 February 2025
[6] Col. (res.) Dr. Liron A. Libman, Legal Opinion on the Proposed Alternative Strategy, November 7, 2024 (Hebrew)
[7] Department of Defense, Law of War Manual, Office of General Counsel, 2015
[8] Sean Watts, Siege Law, West Point, March 4, 2022
[9] FM 3-06, Urban Operations, 2017, Headquarters, Department of the Army, 2006
[10] UK, THE JOINT SERVICE MANUAL OF THE LAW OF ARMED CONFLICT, 5.34.1 (2004)
[11] The principle of proportionality in international law permits attacks expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or any combination of the above. Commanders must, however, weigh expected harm against the concrete and direct military advantage anticipated from the attack. See International Expert Meeting Report: The Principle of Proportionality, International Committee of the Red Cross, September 3, 2018.
[12] Amir Ettinger, “After the Dispute over Humanitarian Aid: Call for an Urgent Meeting of the Foreign Affairs and Defense Committee” (Hebrew), Israel Hayom, May 15, 2025.
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Colonel (res.) Prof. Gabi Siboni
Prof. Siboni was director of the military and strategic affairs program, and the cyber research program, of the Institute for National Security Studies (INSS) from 2006-2020, where he founded academic journals on these matters. He serves as a senior consultant to the IDF and other Israeli security organizations and the security industry. He holds a B.Sc. and M.Sc. in engineering from Tel Aviv University and a Ph.D. in Geographic Information Systems (GIS) from Ben-Gurion University. More may be found here. His list of publications may be found here.
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Recent publications
Gaza: Until When?
Israel’s Veteran Peace Partners: The Role of Egypt and Jordan in the Context of Trump’s Gaza Plan
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