The Short Answer
International law recognizes every state's right to self-defense and allows attacks on legitimate military targets. "Proportionality" does not mean equal casualties; it means the expected civilian harm must not be excessive compared to the concrete military advantage expected. The law also places responsibility on parties like Hamas that deliberately use civilians and civilian sites as shields.
The core rules
The law of armed conflict rests on distinction (attack only military objectives), proportionality (expected incidental civilian harm must not be excessive relative to the anticipated military advantage), and precaution (take feasible steps to minimize civilian harm, such as warnings).
Proportionality is often misunderstood as requiring equal numbers of casualties on both sides. It does not. A legitimate military target — such as a command center or rocket launcher — remains lawful even when an enemy has placed it among civilians, provided the expected civilian harm is not excessive.
Human shields and responsibility
Using civilians or protected sites such as hospitals and schools to shield military operations is a war crime. Israel has documented extensive Hamas use of hospitals, schools and mosques for tunnels, weapons storage and command centers, and warned civilians to evacuate before many strikes.
Israel's military has its own legal advisors who review targeting decisions, and Israel has an independent judiciary that investigates alleged violations — one of the reasons Israel argues international courts should defer to its domestic legal system.
Key Facts
- UN Charter Art. 51 recognizes self-defense
- Proportionality ≠ equal casualties
- Using human shields is a war crime
- Israel has independent military legal review and courts
Sources & Further Reading
- UN Charter, Chapter VII (Article 51)
- ICRC Customary IHL — Rule 14: Proportionality in Attack
- ICRC Customary IHL — Rule 97: Human Shields
- John Spencer — Modern War Institute at West Point
This answer reflects publicly available information as of October 2026.