Courts continue to grapple with whether certain workers are “engaged in interstate commerce” for purposes of the exemption from the Federal Arbitration Act for transportation workers. The Ninth Circuit recently held that drivers transporting goods from Domino’s Pizza supply centers to franchisees were engaged in interstate commerce, even though the drivers did not cross state lines. Domino’s asked the U.S. Supreme Court for a review. In a surprise move, the Court granted review and, without oral argument or merits briefing, vacated the Ninth Circuit’s decision, sending the case back for further proceedings in light of its decision this summer in Southwest Airlines Co. v. Saxon. The Court’s action is difficult to interpret, because, in Saxon, the Court specifically noted it was not opining on what it means to be “engaged in interstate commerce,” the issue at the heart of the Domino’s Pizza case. Lower courts are left to decipher the Court’s meaning, a process we are closely watching as it unfolds.