WASHINGTON - U.S. courts will not be the world forum for lawsuits brought by victims of human-rights abuses abroad who seek damages from multinational corporations or deposed tyrants, the Supreme Court declared Wednesday.

In a decision welcomed by corporate leaders and decried by human-rights activists, the justices said U.S. courts are limited mostly to deciding disputes over conduct that took place on American territory, not on foreign soil.

By a 9-0 vote, the high court tossed out a closely watched lawsuit brought by Nigerians against Royal Dutch Petroleum for allegedly conspiring with the Nigerian regime in a campaign of rape, torture and murder in the oil-rich delta in the early 1990s.

This suit had become a test of whether American courts could serve as a judicial forum for victims of gross violations of international law.

In recent decades, these suits have been brought into U.S. courts under a once-obscure 18th century law, known as the Alien Tort Statute, which said the courts could resolve claims arising under the "law of nations."

It was adopted by the first Congress as a way of dealing with pirates and their stolen goods.

But in the 1980s, human-rights advocates rediscovered the law and used it to bring claims of international justice into America's courts.

Many of the suits targeted multinational companies for abusing workers or their environment. The best-known suit led to a multibillion-dollar judgment in Hawaii against the estate of former Philippines President Ferdinand Marcos.

But the Supreme Court has cast a skeptical eye on these far-ranging lawsuits, and Chief Justice John G. Roberts Jr. announced an opinion Wednesday that will close the U.S. courts to most of them.

He invoked a legal doctrine known as the "presumption against extraterritorial application." It means that unless Congress clearly says otherwise, it is understood that U.S. law "governs domestically, but does not rule the world," Roberts said.

Explaining the opinion from the bench, the chief justice said most of these human-rights claims, including the Nigerian suit, involve "foreign plaintiffs suing foreign defendants for conduct that took place on foreign soil."

There is no reason to believe the first Congress wanted to make America's courts the forum for deciding disputes from around the world, he said.