Federal court judges cannot dismiss a lawsuit after sending a dispute to arbitration if a party requests that the case be kept alive pending the outcome of those alternative proceedings, a unanimous U.S. Supreme Court ruled Thursday.

The court’s decision in Smith v. Spizzirri overturned a line of cases from the U.S. Court of Appeals for the Ninth Circuit holding that judges can dismiss, rather than stay, lawsuits in which all of the claims are covered by an arbitration agreement.