On December 1, 2015, the Supreme Court decided OBB Personenverkehr AG v. Sachs. This case concerns the scope of the commercial activity exception to the Foreign Sovereign Immunities Act (FSIA). Under this exception, sovereign immunity does not bar a lawsuit “based on a commercial activity carried on in the United States by [a] foreign state.” In this case Carol Sachs sued the Austrian national railroad when she suffered serious injuries while attempting to board an Austrian train. The question is whether Sachs’ purchase of her rail pass in the United States brought her suit within the commercial activity exception. The U.S. Court of Appeals for the Ninth Circuit held that it did. -- By a vote of 9-0, the Supreme Court reversed the judgment of the Ninth Circuit. Chief Justice Roberts delivered the opinion for a unanimous Court, holding that Sachs’ suit was “based on” the railway’s conduct in Austria and therefore outside the FSIA’s commercial activity exception. -- To discuss the case, we have Edwin D. Williamson, who is Of Counsel at Sullivan & Cromwell LLP.