Proportionality

Under IHL (Additional Protocol I to the Geneva Conventions, Article 51), an attack violates proportionality if it may be expected to cause incidental civilian harm — deaths, injuries, or damage to civilian objects — that is excessive in relation to the concrete and direct military advantage anticipated. This is a prospective, military-judgment standard made at the time of the attack decision. It is not a casualty ratio. High civilian casualties are not per se evidence of disproportionality; the question is whether the anticipated military advantage justified the foreseeable civilian harm.

In public discourse, "proportionality" is frequently used to mean parity of casualties — the argument that because Palestinian deaths vastly exceed Israeli deaths, the response is disproportionate. This usage does not reflect the legal standard and is not how IHL assesses military conduct. Its use conflates scale of harm with legality of conduct.

Human rights organizations and some legal scholars argue that specific Israeli operations — including strikes on hospitals, refugee camps, and densely populated areas — violated IHL proportionality standards because the foreseeable civilian harm was excessive relative to the military objective. They argue that "military advantage" cannot justify the scale of destruction in Gaza.