Jus ad bellum

Jus ad bellum (ju:s or dʒʌs) refers to "the conditions under which States may resort to war or to the use of armed force in general." This is distinct from the set of rules that ought to be followed during a war, known as jus in bello, which govern the behavior of parties in an armed conflict.cite web|title="Can jus ad bellum override jus in bello?"|url=International Committee of the Red Cross |date=23 Jan 2015 |access-date=8 March 2023 Jus ad bellum is sometimes considered a part of the laws of war, but the term "laws of war" is more often considered to refer only to jus in bello, which, as noted above, concerns whether a war is conducted justly, or lawfully (regardless of whether the initiation of hostilities was just). Jus ad bellum rules focus on the criteria concerning what conditions make an armed conflict just, or lawful." Under modern public international law, the UN Charter establishes the fundamental rules of the jus ad bellum. Article 2, paragraph 4 of the Charter states: "All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any State, or in any other manner inconsistent with the purposes of the United Nations." Article 51 of the UN Charter later clarifies: "Nothing in the present Charter shall impair the inherent right of individual or collective self-defense if an armed attack occurs against a Member of the United Nations." An international agreement limiting the justifiable reasons for a country to declare war against another is concerned with jus ad bellum. In addition to bilateral non-aggression pacts, the twentieth century saw multilateral treaties defining entirely new restrictions against going to war.