In the past, participants in private foreign arbitrations often have sought evidence by taking advantage of U.S.-style discovery practices in parallel U.S. court proceedings, potentially expanding discovery far beyond the rules of the arbitration tribunal. The U.S. Supreme Court has just ruled that this use of U.S. discovery is impermissible, in ZF Automotive US, Inc. v. Luxshare, Ltd., Nos. 21-401 and 21-518.