Legal Definitions - international humanitarian law

International humanitarian law (IHL), often referred to as the law of war or the law of armed conflict, is a set of international rules that aim to limit the effects of armed conflict for humanitarian reasons. It protects people who are not, or are no longer, participating in hostilities and restricts the means and methods of warfare.

This body of law applies during armed conflicts, whether they are between states or between a state and an organized armed group. It addresses two main aspects:

• When states can resort to war: This part of IHL (historically known as jus ad bellum) sets the conditions under which it is legally permissible for a state to use force against another state. Generally, this is limited to self-defense or actions authorized by the United Nations Security Council.
• How states and armed groups must behave during war: This part of IHL (historically known as jus in bello) dictates the rules of conduct once a conflict has begun. It aims to minimize suffering by protecting civilians, wounded soldiers, prisoners of war, and medical personnel, and by prohibiting certain weapons and tactics.

IHL is distinct from international human rights law, though they can overlap. While human rights law applies at all times (in peace and in war), IHL is specifically designed for situations of armed conflict. Many of its core principles are found in international treaties, most notably the Geneva Conventions of 1949 and their Additional Protocols.

Here are some examples illustrating how international humanitarian law applies:

• Example 1: Protecting Medical Facilities in Conflict Zones

  Imagine an armed conflict where one side's military forces are advancing through a city. They receive intelligence that enemy combatants are operating near a clearly marked hospital. Under international humanitarian law, the hospital, its staff, and its patients are protected and cannot be targeted, even if enemy combatants are in the vicinity. The attacking forces must take all feasible precautions to avoid harming the hospital and ensure the safety of those inside. If enemy combatants are using the hospital for military purposes, its protected status might be lost, but only after a warning and a reasonable time limit, and only if the military use is proven. This demonstrates the "how states must behave during war" aspect (jus in bello) by emphasizing the protection of non-combatants and civilian infrastructure.

• Example 2: Treatment of Captured Combatants

  During a border skirmish, soldiers from Country A capture several enemy combatants from Country B. According to international humanitarian law, specifically the Geneva Conventions, these captured individuals must be treated humanely. They cannot be tortured, subjected to degrading treatment, or denied basic necessities like food, water, and medical care. They must be identified as prisoners of war (POWs) and given specific rights, including the right to communicate with their families and be visited by representatives of an impartial humanitarian organization like the International Committee of the Red Cross. This illustrates the "how states must behave during war" aspect (jus in bello) by setting clear standards for the treatment of those no longer able to fight.

• Example 3: Justification for Military Intervention

  A powerful nation, Country X, considers launching a military strike against Country Y, claiming that Country Y is developing weapons that could pose a future threat. However, Country Y has not attacked Country X, nor has the United Nations Security Council authorized any military action. Under international humanitarian law's rules on "when states can resort to war" (jus ad bellum), Country X would likely be in violation if it initiated an attack. The law generally permits the use of force only in self-defense against an actual or imminent armed attack, or when authorized by the UN Security Council to maintain international peace and security. A preemptive strike based on a perceived future threat, without meeting these strict conditions, would be considered an illegal act of aggression under IHL.