The case of the National Labor Relations Board (NLRB) v. Enterprise Association of Steam, Hot Water, Hydraulic Sprinkler, Pneumatic Tube, Ice Machine & General Pipefitters of New York and Vicinity, Local Union No. 638 in 1976 involved a dispute over whether certain actions by the union constituted unfair labor practices under the National Labor Relations Act (NLRA). The NLRB had found that the union's refusal to refer nonunion workers for employment opportunities was discriminatory and violated Section 8(b)(2) and (1)(A) of NLRA. However, on appeal to Supreme Court it held that such referral system did not violate NLRA as long as it operated in a nondiscriminatory manner. It further stated that although unions have an obligation to represent all employees fairly regardless if they are members or not but this does not mean they must treat them identically with their own members.

In the dissenting opinion for the case of NATIONAL LABOR RELATIONS BOARD v. ENTERPRISE ASSOCIATION OF STEAM, HOT WATER, HYDRAULIC SPRINKLER, PNEUMATIC TUBE, ICE MACHINE & GENERAL PIPEFITTERS OF NEW YORK AND VICINITY, LOCAL UNION NO. 638 (1976), Justice William J Brennan Jr., joined by Justices Stewart and Marshall disagreed with the majority's decision that a union could be held liable for unfair labor practices committed by its business agent even if it did not authorize or ratify those actions. The dissent argued that this interpretation was inconsistent with previous rulings and legislative intent behind Section 8(b) of National Labor Relations Act which requires proof of authorization or ratification to hold a union responsible for acts committed on its behalf. They contended that such an expansive reading would unfairly penalize unions without clear evidence they endorsed illegal conduct.