The Encyclopedia is a project of the Geneva Academy of International Humanitarian Law and Human Rights launched on 2 December 2013. The Enyclopedia aims to provide accurate, up-to-date information on weapons, the effects of their use, and their regulation under public international law, in a format that is accessible to non-specialists.+ Find out more
Under jus ad bellum, a state is entitled to use military force in self-defence against an "armed attack" against it. But in accordance with customary international law the principle of necessity holds that force may only be lawfully used where it is necessary. Thus, for example, other actions (e.g. political, economic, diplomatic) may be sufficient to repel the armed attack. In the Oil Platforms case between Iran and the United States of America (USA), the International Court of Justice adjudgedSee paragraph 76 of its 2003 judgment. that the available evidence did not adequately support the US contention as to the significance of the military presence and activity on one of the oil platforms the US had attacked and no evidence was offered in respect of two other complexes. However, even had it accepted the US contentions, for the purposes of discussion, the Court was not satisfied that the attacks on the platforms were necessary to respond to an Iranian attack on the Sea Isle City and the alleged mining of the USS Samuel B. Roberts.
Under international human rights law and criminal justice standards, any use of force for law enforcement purposes must be strictly necessary. Thus, for example, under Principle 4 of the 1990 Basic Principles on the Use of Force and Firearms by Law Enforcement Officials:
Law enforcement officials, in carrying out their duty, shall, as far as possible, apply non-violent means before resorting to the use of force and firearms. They may use force and firearms only if other means remain ineffective or without any promise of achieving the intended result.
The doctrine of military necessity under IHL is controversial insofar as some consider it a permissive principle (allowing death and destruction) and others consider it a limiting principle (e.g. killing a certain person must be militarily necessary). Arguably, the better view is that military necessity is generally a permissive principle while the principle of humanity is inherently limiting.
Last updated on: 30 November 2013