A local Teamsters Union represented drivers and helpers who worked for linen suppliers in New England. Ten linen suppliers, including Charles D. Bonanno Linen Service, Inc. (Bonanno) (defendant), formed a multiemployer unit to negotiate with the Teamsters. Bonanno’s president joined the association’s negotiating committee and authorized it to represent Bonanno. When negotiations reached an impasse, the union initiated a selective strike against Bonanno that resulted in most of the linen suppliers locking out their drivers. Bonanno hired new drivers to permanently replace all its striking drivers and purportedly withdrew from the association. The other suppliers ended the lockout and resumed multiemployer negotiations without Bonanno, resulting in a new contract. The union challenged Bonanno’s withdrawing from the multiemployer unit without consent as an unfair labor practice, arguing that the new contract should bind Bonanno. The National Labor Relations Board (NLRB) found Bonanno’s withdrawal untimely and ineffective and ordered it to sign and adhere to the new contract retroactively. The appellate court affirmed, and Bonanno appealed to the Supreme Court.