What does the International Court of Justice do?

Peace Palace — even the name of the brick building in the Hague with its ornamental turrets, dormers and arcades leaves no doubt about its founding claim for settling international conflicts. But it took a while to begin this task.

World War I broke out just one year after the building's completion in 1913. The building stood through two world wars and, for a time, housed the legal umbrella organisation of the League of Nations.

When the United Nations was founded in aftermath of World War II, the Hague once again became the center of international law. But while all other main UN bodies were located in New York, the international court of justice (ICJ) began its work in the Peace Palace in the Netherlands.

What is the International Court of Justice?

"The International Court of Justice shall be the principal judicial organ of the United Nations," states Chapter XIV, article 92 of the UN Charter, the authoritative international treaty that governs the United Nations. The 193 member states are automatically parties to the treaty and must comply with ICJ decisions — at least, according to the charter.

The court is made up of 15 judges, each of whom must come from a different country and are elected by the UN General Assembly and the Security Council. Five new judges are rotated into the panel every three years. As in the UN Security Council, fixed quotas ensure they represent all regions of the world. Since March, the body has been chaired by the Japanese judge Yuji Iwasawa, with Julia Sebutinde, of Uganda, as vice president.

The ICJ hears cases in which states act as adversaries. That differs from the International criminal court (ICC), which handles trials for individuals accused of charges such as war crimes.

What is the court's jurisdiction?

While one might expect the signing of the UN Charter to result in a clear mandate for all states, this isn't the case. The ICJ only has blanket jurisdiction if all states involved have issued a declaration of submission in which they transfer all international legal disputes to the court. Germany made such a declaration in 2008, as have around a third of the UN member states.

States that have not made this declaration can, in the event of a dispute, voluntarily agree with each other to bring the matter before the ICJ. However, there are also cases in which these states can be accused before the ICJ without individual consent. This is the case when the plaintiff refers to individual UN conventions for which the ICJ is designated as a court, and which have also been signed by the defendant state.

A prominent example of this would be the UN Genocide Convention of 1948, Article 9 of which states that disputes "shall be submitted to the International Court of Justice at the request of any of the parties to the dispute." Ukraine based its lawsuit against Russia on this agreement shortly after the invasion began in early 2022. Another example is the case initiated by Gambia, in which Myanmar must defend itself against the accusation of genocide against the Rohingya.

South Africa's case against Israel is also based on the Genocide Convention. The ICJ is currently examining whether Israel is violating the Genocide Convention with its war in the Gaza Strip. In 2024, the ICJ ordered Israel to take precautionary measures to avoid doing so and gave the government until the beginning of 2026 to respond. The ICJ was not involved in the arrest warrant for Israeli Prime Minister Benjamin Netanyahu on charges of war crimes, which was issued by the International criminal court.

The ICJ can also be appointed as a dispute resolution body in bilateral agreements. In 2018, for example, the judges heard a case brought by Iran against certain US sanctions based on a 1955 friendship agreement, ultimately ruling in favor of Tehran. The US had to ensure that medical care, for example, was not affected by sanctions. The administration of then-President Donald Trump subsequently terminated the friendship agreement with Iran.

In 2023, Tehran nevertheless achieved a partial victory in another lawsuit based on the agreement as a legal basis. At that time, the case concerned frozen Iranian funds in US banks. Because the measure had already been enforced prior to the agreement's termination in 2018, the judges considered themselves to have jurisdiction.

No enforcement of rulings

In all three cases — declaration of submission, consent to ICJ dispute resolution or action on the basis of a treaty — the court's rulings are legally binding. There is no provision for appeal proceedings.

In the example of Ukraine's case, the Hague ordered Russia to temporarily halt its war of aggression against Ukraine back in March 2022. A final decision is still pending.