2. The Prohibition of the Use of Force

2. The Prohibition of the Use of Force

The Strength: Article 2(4) is perhaps the most significant rule in international law: members must refrain from the threat or use of force against the territorial integrity of any state.

The Reality: Before 1945, war was a legal tool of statecraft. The Charter turned war into an illegal act, shifting the global paradigm toward collective security. It established the "self-defense" exception (Article 51), creating a clear, if often debated, legal boundary for conflict.