The International Court of Justice (ICJ) is the principal judicial organ of the United Nations (UN), established as an institution to promote the peaceful resolution of disputes between states. It was established in 1945 by the Charter of the United Nations and began work in 1946, succeeding the Permanent Court of International Justice (PCIJ), which had operated under the League of Nations. The ICJ was created to uphold international law and provide a permanent judicial body for settling disputes between sovereign states.
The Court's functioning is governed by the Statute of the International Court of Justice, which is an integral part of the UN Charter. The ICJ exercises two main forms of jurisdiction: contentious jurisdiction to settle legal disputes between states, and advisory jurisdiction to issue non-binding opinions at the request of authorized UN organs. Only states may be parties in contentious cases. Its jurisdiction over a dispute is fundamentally based on the consent of the states involved, as detailed in Article 36 of the Statute. In deciding cases, the Court applies sources of law listed in Article 38(1), which include international conventions (treaties), international custom, and general principles of law. Its judgments are binding only on the parties to that specific case, according to Article 59. Enforcement of its decisions relies on the United Nations Security Council, as stipulated in Article 94 of the UN Charter.
While the Statute itself has remained largely the same, the Court recently amended its procedural rules. On February 28, 2024, the ICJ announced amendments to Articles 81, 82, and 86 of its Rules of Court, which govern the time-limits and procedures for third-party intervention under Article 62 and Article 63 of the Statute. These changes were made to manage the increasing trend of "mass intervention" by multiple states in contentious cases.