Chapter VII of the United Nations Charter
Chapter VII of the United Nations Charter sets out the UN Security Council's powers to maintain peace. It gives the Security Council the authority to "determine the existence of any threat to the peace, breach of the peace, or act of aggression" and to take military and nonmilitary action to "restore international peace and security.” == Rationale == The UN Charter's prohibition of member states of the UN attacking other UN member states is central to the purpose for which the UN was founded in the wake of the destruction of World War II: to prevent war.
Source: Wikipedia — Chapter VII of the United Nations Charter (CC BY-SA 4.0)