WASHINGTON — Foreign political organizations like the Palestinian Liberation Organization and multinational corporations cannot be sued for the torture or murder of persons abroad, including Americans, under the terms of a 1991 U.S. anti-torture law, the Supreme Court ruled unanimously Wednesday.

Only individual perpetrators of such crimes can be held liable, the court said.

The decision is a setback for human rights activists who have sought to extend American law to target inhumane conduct aboard.

The justices said their decision was based on the words of the Torture Victims Protection Act of 1991. That law authorized damage suits against “an individual” acting under the authority of a foreign nation who inflicts torture or murder.

Justice Sonia Sotomayor, speaking for the court, said the “text of the TVPA convinces us that Congress did not extend liability to organizations, sovereign or not. There are no doubt valid arguments for such an extension. But Congress has seen fit to proceed in more modest steps in the Act, and it is not the province of this branch to do otherwise.”

The PLO and the Palestinian Authority had been sued by the family of Azzam Rahim, a U.S. citizen of Palestinian origin, who was arrested in the West Bank while visiting there in 1995. He was allegedly tortured and killed by intelligence officers of the Palestinian Authority, according to the U.S. State Department.

Even if those charges are true, the suit cannot proceed, the high court said, because it does not mention an individual.

Several lower courts have allowed lawsuits that target multinational corporations for allegedly aiding foreign tyrants who tortured or killed. The high court’s opinion cited those decisions and repeated its conclusion that only “natural persons” can be sued under the anti- torture law.

Wednesday’s ruling does not concern a separate law, the Alien Tort Statute, which has opened the door for suits against multinational corporations for other overseas violations of human rights.

The justices heard arguments earlier in a case involving Nigerian plaintiffs who had sued the Royal Dutch Petroleum Co. under that statute. But rather than rule this term on that issue, the justices said they will hear a new round of arguments in the fall. (Copyright © 2012 Los Angeles Times 04/18/12)