A split has emerged among federal appeals courts over whether corporations can be held liable in U.S. courtrooms for human rights abuses conducted overseas—with the California-based Ninth Circuit Court of Appeals, as usual, charting its own course for corporate liability.

That court decided on a 6-5 vote in late October that mining giant Rio Tinto could be held liable under the Alien Tort Statute (ATS) for allegations that the company aided the Papua New Guinea government in committing genocide and war crimes. It was the latest ruling in a running legal dispute over whether companies can be held liable in the ...