The UN Charter, in its Preamble, set an objective: “to establish conditions under which justice and respect for the obligations arising from treaties and other sources of international law can be maintained”. Ever since, the development of, and respect for international law has been a key part of the work of the Organization. This work is carried out in many ways – by courts, tribunals, multilateral treaties – and by the Security Council, which can approve peacekeeping missions, impose sanctions, or authorize the use of force when there is a threat to international peace and security, if it deems this necessary. These powers are given to it by the UN Charter, which is considered an international treaty. As such, it is an instrument of international law, and UN Member States are bound by it. The UN Charter codifies the major principles of international relations, from sovereign equality of States to the prohibition of the use of force in international relations.
International law is the set of rules generally regarded and accepted as binding in relations between states and between nations. It serves as a framework for the practice of stable and organized international relations. International law differs from state-based legal systems in that it is primarily applicable to countries rather than to private citizens. National law may become international law when treaties delegate national jurisdiction to supranational tribunals such as the European Court of Human Rights or the International Criminal Court. Treaties such as the Geneva Conventions may require national law to conform to respective parts.
Much of international law is consent-based governance. This means that a state member is not obliged to abide by this type of international law, unless it has expressly consented to a particular course of conduct. This is an issue of state sovereignty. However, other aspects of international law are not consent-based but still are obligatory upon state and non-state actors such as customary international law and peremptory norms (jus cogens).