Guides · Updated 2026-10-28

The laws of war in plain language

Wars have rules. International humanitarian law (IHL), also called the laws of war or the law of armed conflict, limits how fighting may be conducted and protects people who are not, or are no longer, taking part. It applies to every party to an armed conflict, state forces and armed groups alike, whatever the reasons for the war. It is separate from the question of whether a war was lawful to start in the first place, which is governed by other rules, mainly the UN Charter.

Where the rules come from

The core texts are the four Geneva Conventions of 1949, ratified by every state, and their Additional Protocols of 1977, which most but not all states have joined. Other treaties ban or restrict specific weapons, such as chemical and biological weapons and anti-personnel landmines. Many rules are also part of customary law, which binds all parties even if they have not signed a treaty. The International Committee of the Red Cross (ICRC) has a special role in promoting and explaining these rules and in visiting detainees.

Three key principles

Distinction. Parties must always distinguish between combatants and civilians, and between military objectives and civilian objects. Attacks may only be directed at military objectives.
Proportionality. An attack is prohibited if the expected harm to civilians would be excessive compared with the concrete military advantage anticipated.
Precaution. Parties must take feasible steps to avoid or minimise civilian harm, for example by checking targets and giving effective warnings where possible.

Who and what is protected

Civilians, the wounded and sick, prisoners of war and detainees, medical staff and hospitals, and humanitarian workers all have specific protections. Objects essential for survival, such as food supplies and drinking water installations, are protected, and starving civilians as a method of warfare is prohibited. Protection can be lost in some cases, for example when a civilian takes a direct part in hostilities, which is one reason legal assessments are complex.

Detention and missing people

People detained in connection with a conflict must be treated humanely, and families have a right to know what has happened to missing relatives. The ICRC visits detainees and helps exchange family messages, and its tracing services help families search for people separated by war.

Who decides if a rule was broken

A report that a hospital or a school was hit does not by itself show that the law was broken; that depends on facts such as what the target was and what the attacker knew at the time. Investigations are carried out by states, UN commissions, courts such as the International Criminal Court, and independent researchers, and they can take years. This is one reason why JellyDock Conflict Watch reports what happened as described by outlets and does not label events as legal or illegal.