The collective-bargaining agreement (CBA) between the Retail Clerks Union, Local 770 (defendant), and Boys Markets, Inc. (plaintiff) prohibited strikes and required arbitration of all disputes. When the union called a strike and began picketing a Boys Market supermarket, the company demanded that the union end the strike and follow the arbitration process. When the strike continued the next day, the company filed a complaint in state court seeking injunctive relief and compliance with the arbitration provisions. The union promptly removed the case to federal court, which ordered the parties to arbitrate and enjoined the strike, picketing, and further attempts to induce work stoppages. The appellate court reversed under Sinclair Refining Co. v. Atkinson, 370 U.S. 195 (1962), which held that federal courts cannot enjoin strikes that violate no-strike provisions of a CBA. The Supreme Court granted review.