International law―the recognized rules of behavior among nations based on customary practices and treaties, among them the United Nations Charter and the Universal Declaration of Human Rights―has been agreed upon by large and small nations alike. To implement this law, the nations of the world have established a UN Security Council (to maintain international peace and security) and a variety of international courts, including the UN’s International Court of Justice (which adjudicates disputes between nations and gives advisory opinions on international legal issues) and the International Criminal Court (which prosecutes individuals for crimes of genocide, crimes against humanity, war crimes, and the crime of aggression).