In the case of Southport Petroleum Co. v. National Labor Relations Board, 1941, the U.S Supreme Court upheld a decision by the National Labor Relations Board (NLRB) that found Southport Petroleum Company guilty of unfair labor practices under Section 8(1) and (3) of the National Labor Relations Act. The company had refused to bargain with a union chosen by its employees and discharged several workers for their union activities. The court ruled that substantial evidence supported these findings by NLRB, rejecting Southport's argument that it was not engaged in interstate commerce as defined under the act and therefore outside NLRB's jurisdiction. This ruling affirmed NLRB’s authority over companies involved indirectly in interstate commerce.

In the dissenting opinion for Southport Petroleum Co. v. National Labor Relations Board, the justice argued that the majority's decision to uphold a cease and desist order against Southport Petroleum was based on an incorrect interpretation of labor law. The justice contended that there was no substantial evidence showing that Southport had interfered with its employees' rights to form, join or assist labor organizations as protected by Section 7 of the National Labor Relations Act (NLRA). He further stated that even if such interference occurred, it did not necessarily constitute unfair labor practices under Section 8(1) of NLRA unless it resulted in restraint or coercion. In his view, mere persuasion should not be equated with coercion or restraint; thus he disagreed with NLRB’s broad interpretation of what constitutes employer interference and domination over employee unions. Moreover, he expressed concern about potential abuse of power by NLRB due to lack of judicial review over its decisions which could infringe upon employers’ free speech rights guaranteed by First Amendment.