Belgium's highest court dismissed war crimes complaints against the first President Bush, Dick Cheney and Colin L. Powell for their actions during the Persian Gulf war in 1991, when Mr. Cheney was the secretary of defense and General Powell was the American commander. A war crimes case against Prime Minister Ariel Sharon of Israel, for his military role in the killing of Palestinians in Lebanon in 1982, was also dropped. The court said Belgium no longer had a legal basis to charge them. The cases were brought under Belgium's universal jurisdiction law, which allowed war crimes complaints against foreigners. The law was amended last month, guaranteeing immunity for world leaders and leading to the dismissal, which cannot be appealed.