The United Nations Security Council (UNSC) is the most powerful part of the United Nations. The Security Council deals with maintaining peace and security between nations. For members of the UN to engage in war or major military activity against another country or a large armed group outside of their own country they are supposed to have the agreement of the Security Council to do so but recent history shows that this rule is often not closely followed by everyone. All members of the UN retain the right to "self-defense"; they can engage in actions to defend their people and land whenever this becomes necessary but are then expected to refer the matter to the Security Council as soon as they can.