In the case of National Labor Relations Board v. Pacific Greyhound Lines, Inc., 1937, the U.S Supreme Court ruled in favor of the National Labor Relations Board (NLRB). The NLRB had charged Pacific Greyhound Lines with unfair labor practices for interfering with its employees' rights to form and join a union under Section 7 of the Wagner Act or National Labor Relations Act. The company argued that it was not engaged in interstate commerce as defined by Congress and thus should not be subject to federal regulation. However, the court held that because Pacific Greyhound's bus operations were part of a "flow" of interstate commerce due to their significant involvement in transporting passengers across state lines, they fell within congressional jurisdiction over such matters. Therefore, they were required to comply with federal labor laws protecting workers' rights.

The dissenting opinion in the case of National Labor Relations Board v. Pacific Greyhound Lines, Inc., argued that the majority's decision to uphold the National Labor Relations Board's (NLRB) order was incorrect. The dissent contended that there was insufficient evidence to support NLRB’s claim that Pacific Greyhound Lines had engaged in unfair labor practices by interfering with its employees' rights to form, join or assist labor organizations and bargain collectively through representatives of their own choosing. They believed this interference allegation stemmed from a misunderstanding between management and union organizers rather than an intentional violation of employee rights under Section 7 of the National Labor Relations Act. Furthermore, they disagreed with NLRB’s assertion that Pacific Greyhound had dominated or interfered with the formation or administration of any labor organization, arguing instead it merely sought to ensure a fair election process for all parties involved.