The International Court of Justice is ineffective, largely due to the sensitive nature of cases brought before it. In many cases, effective litigation would require the disclosure of vital national security information, which most nations are reluctant to do.
Only a minority of UN members have, in the history of the International Court, accepted its compulsory jurisdiction; and then only on matters which did not jeopardize their national security. Of the 15 permanent World Court judges who decided, in 1985, that the Court had the jurisdiction to try Nicaragua's claim against the USA, 10 were from countries which themselves had refused to accept the compulsory jurisdiction of the Court.
In 1962, the former Soviet Union refused to comply with the Court's judgement that all members must pay their assessed share of UN peacekeeping operations. In 1973, France refused to appear before the Court on charges from Australia and New Zealand that her nuclear devices testing in the South Pacific was unlawful. In 1985, the USA refused to participate in the Court on charges brought against her by Nicaragua.