For example, would a state have to wait to absorb an armed attack before it could defend itself? How should terrorists be captured and treated when captured? Finally, how can a nation involved in an armed conflict abroad distinguish between terrorist combatants and ordinary civilians? September 11, 2001, ushered in a new approach to counter-terrorism in armed conflict.

Prior to the attacks of September 11, 2001, it wasn’t clear how a state could combat terrorism under the laws of war. Additionally, Article 51 of the UN Charter permits the use of force in self-defense only “if an armed attack occurs.” The United Nations Charter prohibits states from using force in international relations “against the territorial integrity or political independence” of other countries. The United Nations Charter doesn’t make any mention of terrorists or how terrorism relates to armed conflict. Latin for “law in war”, jus in bello consists of rules relating to proper and improper kinds of weapons and military tactics, and rules relating to the treatment of prisoners of war and civilians.

Jus in bello is the international law that governs the way armed conflict proceeds.

5 law of armed conflict principles