THE HAGUE, Netherlands — The United Nations’ highest court on Wednesday rejected nuclear disarmament cases filed by the tiny Pacific nation of the Marshall Islands against Britain, India and Pakistan, saying it did not have jurisdiction.

In a blow to disarmament activists, the International Court of Justice ruled that the Marshall Islands failed to prove that a legal dispute over disarmament existed between it and the three nuclear powers before the case was filed in 2014, and that “consequently the court lacks jurisdiction.”

It took a casting vote by the court’s President Ronny Abraham to break an eight-eight deadlock between the court’s 16 judges on the question of jurisdiction in the case against Britain. In the cases against India and Pakistan, the margin was nive-seven.

Phon van den Biesen, a Dutch lawyer who represented the Marshall Islands, said he was deeply disappointed by the rulings.

“If the court keeps creating this sort of threshold, what is the court for?” he said. “It’s a dispute that is clear to all of the world except for eight judges here.”

Abraham acknowledged that the Marshall Islands has a particular interest in nuclear disarmament “by virtue of “the suffering which its people endured as a result of it being used as a site for extensive nuclear testing programs.”

At hearings in March, Marshall Islands representative Tony deBrum said he watched one of the U.S. nuclear tests in his home country as a 9-year-old boy while fishing with his grandfather.

“The entire sky turned blood red,” he told judges in an emotional speech. He said some of his country’s islands were “vaporized” by the tests.

The Marshall Islands originally filed cases against all nine nations that have declared or are believed to possess nuclear weapons: The U.S., Russia, Britain, France, China, India, Pakistan, Israel and North Korea. But only the cases against Britain, India and Pakistan got to the preliminary stage of proceedings.

The court has previously delved into the issue of nuclear weapons. In a landmark 1996 advisory opinion, the court said that using or threatening to use nuclear arms would “generally be contrary to” the laws of war and humanitarian law.

But it added that it could not definitively rule on whether the threat or use of nuclear weapons would be legal “in an extreme circumstance of self-defense, in which the very survival of a state would be at stake.”

The judges in 1996 also unanimously stated that there is a legal obligation “to pursue in good faith” nuclear disarmament talks.