The U.S. Supreme Court case Pittsburgh Plate Glass Co. v. United States in 1958 revolved around the issue of whether a labor union could be considered an "interested party" under Section 4 of the Clayton Act, thus allowing it to sue for treble damages resulting from antitrust violations that affected its members' wages and working conditions. The court ruled against the labor union, stating that unions were not directly injured by such violations and therefore did not qualify as interested parties under this act. This decision was based on their interpretation of the term "business or property," which they believed referred only to commercial interests rather than employment relationships or other non-commercial concerns.

In the dissenting opinion for Pittsburgh Plate Glass Co. v. United States, Justice Brennan disagreed with the majority's ruling that evidence obtained through an illegal search and seizure could be used in a grand jury proceeding. He argued that this decision contradicted previous rulings which had established that illegally seized evidence was not admissible in any court proceedings, including grand juries. Furthermore, he contended that allowing such evidence to be presented before a grand jury would undermine citizens' Fourth Amendment rights against unreasonable searches and seizures by encouraging law enforcement officials to conduct unlawful searches with impunity since they know any incriminating materials found can still be used before a grand jury despite being inadmissible at trial.