- What “Proportionality” Means in the Law of War
- the Geneva Conventions
- Additional Protocol I (1977)
- customary international law
- It does not compare casualties on each side.
- It compares civilian harm vs military advantage.
- Proportionality Is About Civilian Harm (Collateral Damage)
- a legitimate military target is attacked
- but civilians or civilian property may also be harmed.
- If a Target Is Purely Military
- destroying an enemy battalion
- bombing a military base
- sinking a warship
- Example: “2 soldiers vs 100 soldiers”
- Is the target military?
- Is the attack necessary and lawful?
- What About Bombing a BuildingWithBabies Inside?
- weapons storage
- command center
- rocket launch site
- militant headquarters
- expected civilian casualties
- the military advantage of destroying the target
- whether other options exist
- How the IDF Says It Implements Proportionality
- Legal advisors in operational planning
- Intelligence assessments
- number of civilians likely present
- military importance of the target.
- Target verification
- Warning civilians whenfeasible
- phone calls
- text messages
- leaflet drops
- “roof knocking” warning munitions.
- The Proportionality Judgment Is Predictive
- Why Proportionality Is Controversial
- “excessive” is not mathematically defined
- commanders must make judgment calls
- different observers may evaluate the same strike differently.
- Important Additional Rules
- Proportionality does not compare casualties on each side.
- It compares expected civilian harm to military advantage.
- It mainly applies to collateral damage, not enemy combatant casualties.
- A building used for military purposes may be attacked even if civilians are present, but the attack must not cause excessive civilian harm relative to the military benefit.
- Killing large numbers of enemy soldiers is lawful if they are legitimate military targets.
- Why Proportionality Is Not Defined Numerically
- a fixed ratio of civilian casualties to military gain
- a maximum number of civilian deaths
- a specific damage limit.
- battlefields are unpredictable
- military advantages differ greatly between targets
- rigid formulas could make lawful operations impossible.
- What Commanders Actually Evaluate
- Military value of the target
- senior commander
- weapons stockpile
- missile launcher
- communications center.
- Expected civilian presence
- how many civilians are nearby
- whether they can evacuate
- whether civilians are being used as shields.
- Type of weapon used
- precision-guided missile
- artillery shell
- large air-dropped bomb.
- Timing of the attack
- reduce civilian presence
- wait for nighttime
- wait for evacuation.
- The Decision Is Made Before the Strike
- Why Different Armies Reach Different Conclusions
- intelligence quality
- tolerance for risk to their own forces
- interpretation of military advantage.
- a major command center
- a weapons factory
- a senior operational leader
- Human Shields Complicate the Analysis
- the target may still be lawful
- but proportionality still applies.
- Why This Rule Is Often Misunderstood
- equal casualties on both sides
- retaliation limits
- a numerical ratio.
- Why Critics Say the Rule Is Too Vague
- “excessive” is subjective
- military advantage can be interpreted broadly
- real-time decisions are complex.
- How Courts Evaluate Proportionality
- Was the target a legitimate military objective?
- What did commanders reasonably expect before the attack?
- Were feasible precautions taken?
- Was the expected civilian harm excessive relative to the anticipated military gain?
- Proportionality in international law does not use numerical formulas.
- It balances expected civilian harm against military advantage.
- The assessment is made before the attack, based on available intelligence.
- Because the rule requires judgment, different militaries may interpret it differently.
- Beit Sourik Case (2004) – The Security Barrier
- Israel has the right to build the barrier for security reasons.
- But parts of the route caused disproportionate harm to Palestinian civilians.
- Rational connection The measure must help achieve the military/security objective.
- Least harmful means If several options exist, the one causing less civilian harm should be chosen.
- Proportional balance The harm caused must not be disproportionate to the security benefit.
- Targeted Killing Case (2006)
- the target must be directly participating in hostilities
- capture should be considered if feasible
- proportionality must be respected
- civilian harm must be minimized
- post-operation investigations should occur when civilians are harmed.
- Human Shield Case (2005)
- civilians cannot be used to reduce risks to soldiers
- doing so violates the protection owed to civilians.
- Gaza Border Rules of Engagement Case (2018)
- the events were part of an armed conflict with Hamas
- the IDF rules of engagement were consistent with international law
- live fire could be used as a last resort to stop infiltration or danger.
- Assigned Residence Case (2002)
- a genuine security need
- a connection between the person and the threat
- that the measure was not excessive.
- Physicians for Human Rights Case (2004)
- allow medical evacuation where possible
- facilitate humanitarian assistance when feasible.
- How the Court Applies Proportionality
- Is the objective legitimate and related to security?
- Does the measure help achieve that objective?
- Is there a less harmful alternative?
- Is the harm excessive relative to the benefit?
- Why These Rulings Are Unusual Internationally
- citizens and NGOs can petition it directly
- it functions both as a constitutional court and a high administrative court.
- international law
- military law
- counter-terrorism policy.
- Beit Sourik (2004) – security barrier route
- Targeted Killings (2006) – rules for lethal counter-terrorism strikes
- Human Shield Case (2005) – prohibition on using civilians in operations
- Gaza Border Case (2018) – legality of IDF live fire rules
- Ajuri (2002) – proportionality in security measures.
- Armed Groups Operating Inside Civilian Areas
- residential buildings
- schools
- mosques
- hospitals
- underground tunnels beneath civilian neighborhoods.
- Use of Human Shields
- voluntary civilian presence
- forced human shielding
- ordinary residential living areas where militants operate.
- Dense Population and Infrastructure
- apartment buildings
- electrical networks
- hospitals
- water systems
- roads and tunnels.
- blast radius
- secondary explosions
- risk to nearby buildings.
- Underground Warfare
- tunnels
- command centers
- weapons storage.
- Real-Time Intelligence Limits
- civilians may move unpredictably
- militants may hide among civilians
- intelligence may be incomplete.
- Risk to Soldiers vs Risk to Civilians
- protecting one’s own soldiers
- minimizing civilian harm.
- sending troops into a building may reduce civilian casualties but increase risk to soldiers
- airstrikes may protect soldiers but increase risk to civilians.
- Time Pressure
- Why Legal Disputes Arise
- different intelligence information
- different views of the military value of the target
- different estimates of expected civilian harm.
- military targets are embedded in civilian areas
- armed groups may use human shields
- dense infrastructure increases collateral damage risks
- intelligence is often incomplete
- commanders must make rapid decisions under uncertainty.
- The Principle of Distinction
- military objectives (which may be attacked)
- civilian objects (which may not be attacked).
- How a Civilian Building Can Become a Military Target
- storing weapons or ammunition
- launching rockets or mortars
- housing command centers
- sheltering combatants during operations
- serving as observation posts
- providing entrances to military tunnels.
- Special Protection for Certain Facilities
- hospitals
- medical units
- religious buildings
- cultural sites.
- storing weapons in a hospital
- firing from a mosque
- operating command centers in protected buildings.
- Proportionality Still Applies
- civilians
- residents
- bystanders
- Precautions in Attack
- choosing precision weapons
- attacking at times when fewer civilians are present
- issuing warnings if possible
- selecting a different method of attack.
- Why This Issue Is Controversial
- civilians may still live in or near those buildings
- destroying the military asset may cause civilian casualties.
- the building was genuinely used for military purposes
- the expected civilian harm was excessive.
- Loss of Protection Is Temporary
- the attacker must verify the military use
- proportionality must be respected
- feasible precautions must be taken to reduce civilian harm.
- Tunnels Can Be Military Objectives
- moving fighters
- storing weapons
- command and control centers
- launching attacks
- infiltrating across borders.
- The Building Above May Become Part of the Military Objective
- a house used as a tunnel entrance
- a building used to access an underground command center
- a structure used to store weapons connected to the tunnel system.
- Proportionality Still Applies
- collapse buildings above
- cause fires or explosions
- injure civilians nearby.
- Precautions in Attack
- using smaller or precision-guided munitions
- striking at times when civilians are less likely to be present
- issuing warnings if possible
- targeting tunnel entrances rather than large sections of urban areas.
- Why Tunnels Create Legal Challenges
- the full tunnel network may not be visible
- destroying tunnels may require large explosives
- tunnels may run directly under residential areas.
- Human Shields and Civilian Presence
- using civilians to shield military objectives from attack.
- Legal Disputes Often Focus on Evidence
- whether the tunnel actually existed
- whether the building above was used for military purposes
- whether the expected civilian harm was excessive.
- tunnels used for military purposes are lawful military targets
- buildings used to access or support those tunnels may lose civilian protection
- attacks must still satisfy proportionality and precaution requirements.
- A Building Can Become a Military Objective
- command centers
- weapons storage
- sniper positions
- rocket launch sites
- entrances to tunnels
- communications infrastructure.
- The Size of the Target Does Not Automatically Limit the Strike
- Is the object a military objective?
- Does destroying it provide a concrete military advantage?
- Would the expected civilian harm be excessive compared to that advantage?
- Structural Reality of Buildings
- weapons stored inside walls or basements
- command centers occupying entire floors
- tunnel shafts embedded in foundations.
- Proportionality Still Limits the Attack
- how many civilians are likely inside
- nearby residential buildings
- blast effects and secondary explosions.
- Precautions to Reduce Civilian Harm
- selecting smaller precision weapons
- issuing evacuation warnings
- delaying the strike until civilians leave
- attacking at a different time.
- Why Entire Buildings Are Sometimes Targeted
- military activity occurs inside residential structures
- weapons and fighters are embedded within civilian environments.
- Why These Situations Are Controversial
- whether the building was truly used for military purposes
- whether the expected civilian harm was excessive
- whether sufficient precautions were taken.
- a civilian building can become a military objective if it is used for military purposes
- destroying the entire building may be lawful if that is necessary to neutralize the military objective
- proportionality and precaution rules still apply to limit civilian harm.
- What the Law Actually Requires
- The Law Does Not Require Self-Sacrifice
- commanders must consider civilian harm
- but they are not obligated to expose their soldiers to excessive danger.
- Practical Example
- lower risk to soldiers
- possible collateral damage.
- lower risk to civilians
- much higher risk to soldiers.
- The Role of Proportionality
- military necessity
- civilian protection
- risk to attacking forces.
- Why This Issue Is Often Misunderstood
- soldiers are legitimate combatants
- governments must protect their own forces.
- Why This Debate Is Intense in Urban Warfare
- militants operate among civilians
- civilian casualties are difficult to avoid.
- Israeli Supreme Court View
- military necessity
- proportionality
- civilian protection.
- militaries must take feasible precautions to reduce civilian harm
- attacks causing excessive civilian damage are prohibited
- but the law does not require sacrificing soldiers’ lives to protect enemy civilians.
- The Basic Rule: Civilians Are Protected
- combatants (lawful targets at any time)
- civilians (protected from attack)
- When Civilians Lose Protection
- firing weapons at enemy forces
- launching rockets or missiles
- planting bombs or IEDs
- operating military drones
- directing attacks or providing tactical intelligence during combat.
- The Loss of Protection Is Temporary
- A civilian launching rockets can be targeted while doing so.
- Once they stop and return to ordinary civilian life, they regain protection.
- Continuous Combat Function
- members of militant organizations who regularly carry out attacks
- fighters assigned to operational military roles
- commanders directing combat operations.
- Activities That Do NOT Remove Civilian Protection
- expressing political support for a militant group
- working in civil government institutions
- providing general economic support
- participating in protests.
- The “Human Shield” Problem
- voluntary participation in hostilities
- civilians forced to remain near military assets.
- Why This Rule Is Difficult to Apply
- militants may operate without uniforms
- civilians may temporarily participate in attacks
- intelligence may be incomplete.
- civilians are protected from attack
- they lose protection while directly participating in hostilities
- members of armed groups with continuous combat roles may be lawful targets
- once civilians stop participating in hostilities, they regain protection.
- How the Law Treats Regular Soldiers
- belong to an organized armed force
- operate under a command structure
- carry arms openly
- distinguish themselves from civilians (usually by uniforms or visible insignia).
- Fighters Without Uniforms
- unlawful combatants or
- unprivileged belligerents.
- they can still be lawfully targeted during hostilities
- but they do not receive the same POW protections if captured.
- Why the Uniform Requirement Exists
- What Happens When Fighters Hide Among Civilians
- they remain lawful targets because of their combat role
- but attacks must still follow proportionality and precaution rules.
- Continuous Combat Function
- regularly plan or carry out attacks
- serve as operational fighters
- command combat operations
- Loss of Civilian Protection
- firing weapons
- launching rockets
- planting explosives
- directing attacks.
- Legal Consequences if Captured
- they may be detained as an unlawful combatant
- they may be prosecuted for participation in hostilities
- they do not receive automatic POW immunity.
- Why This Issue Is Controversial
- the classification of fighters can be unclear
- intelligence errors may occur.
- lawful combatants (uniformed soldiers with POW protections)
- unlawful or unprivileged fighters (members of armed groups without uniforms).
- can still be lawfully targeted during hostilities
- may be prosecuted if captured
- do not receive full prisoner-of-war status.
- The Geneva Conventions Were Written After World War II
- two states fighting each other
- uniformed armies
- identifiable battlefields
- clear front lines
- combatants separated from civilians.
- soldiers wear uniforms
- civilians stay outside combat
- captured soldiers become prisoners of war (POWs).
- Modern Conflicts Often Do Not Follow That Model
- terrorist organizations
- insurgent movements
- militias.
- do not wear uniforms
- operate within civilian populations
- fight from residential areas
- blend into civilian society when not fighting.
- Additional Protocols Tried to Address This Problem
- wars of national liberation
- conflicts involving irregular forces
- guerrilla warfare.
- The Legal Category of “Non-International Armed Conflict”
- Problems Created by This Legal Gap
- Urban Warfare
- civilians live
- infrastructure is dense
- fighters operate inside civilian buildings.
- Asymmetry Between States and Armed Groups
- ignore these rules
- deliberately violate them
- target civilians intentionally.
- Why This Debate Continues
- terrorism
- urban warfare
- cyber warfare
- hybrid conflicts.
- fighters may not wear uniforms
- they may operate among civilians
- the legal framework for such conflicts is less detailed.
- Cities Are Not Automatically Protected
- makes an effective contribution to military action, and
- whose destruction offers a definite military advantage.
- military headquarters
- weapons storage sites
- rocket launch positions
- command centers
- military tunnels or bases.
- The Rule of Distinction
- military targets, which may be attacked
- civilians and civilian objects, which may not be intentionally attacked.
- The Proportionality Rule
- Precautions in Attack
- choosing weapons that reduce collateral damage
- timing the attack to avoid civilians when possible
- verifying the target carefully
- issuing warnings if feasible.
- Why Urban Warfare Is So Difficult
- civilians live close to potential military targets
- infrastructure is dense and interconnected
- fighters may operate within residential areas
- military assets may be hidden in civilian buildings or underground.
- Indiscriminate Attacks Are Prohibited
- cannot distinguish between military and civilian targets, or
- uses methods or weapons that strike military targets and civilians without distinction.
- distinction between military targets and civilians
- proportionality to avoid excessive civilian harm
- precautions in attack to minimize civilian casualties
- prohibition of indiscriminate attacks.
- The Legal Rule on Warnings
- Warnings must be effective (meaning civilians have a real chance to leave or seek safety).
- Warnings are required only when feasible.
- What Counts as an “Effective” Warning
- phone calls or text messages
- radio announcements
- leaflet drops
- public broadcasts
- sirens or loudspeaker warnings
- other communication methods.
- Why Warnings Are Not Always Required
- surprise attacks against enemy fighters
- situations where warning would allow the target to escape
- immediate threats where there is no time to warn civilians.
- Limitations of Warnings
- distinction
- proportionality
- precautions in attack
- Practical Challenges
- civilians may not receive the message
- they may not have time or ability to evacuate
- roads or exits may be blocked
- some people may remain voluntarily or under coercion.
- Legal Assessment After an Attack
- Was a warning feasible under the circumstances?
- Was the warning likely to reach civilians?
- Did civilians have a reasonable opportunity to leave?
- attackers must give effective advance warning when feasible
- warnings must provide civilians a real chance to reduce risk
- warnings are not required when circumstances do not permit
- even with warnings, attacks must still satisfy proportionality and distinction.
- The Legal Test Is Not Based on the Final Casualty Count
- the military value of the target
- the expected civilian presence
- the likely collateral damage.
- Outcome vs. Expectation
- Why the Law Uses This Approach
- intelligence may be incomplete
- civilians move unpredictably
- weapons may not behave exactly as expected.
- Civilian Casualties Can Still Trigger Investigations
- Was the target truly a military objective?
- Were precautions taken?
- Was the proportionality assessment reasonable?
- Were warnings given if feasible?
- Why This Rule Is Controversial
- legitimate targets sometimes exist in civilian areas
- outcomes cannot always be predicted perfectly.
- whether the target was a legitimate military objective
- whether commanders expected excessive civilian harm compared to the military advantage
- whether precautions were taken to reduce civilian harm.