In Associated Press et al. v. United States, the Supreme Court ruled that the Associated Press (AP) violated antitrust laws by prohibiting member newspapers from selling or providing news to nonmember organizations as well as making it very difficult for non-member newspapers to join the AP. The court found these practices restrained trade and constituted a monopoly in violation of the Sherman Antitrust Act, which prohibits business activities that reduce competition in marketplace. The decision was significant because it affirmed that newsgathering agencies were not immune from federal antitrust regulations just because they dealt with news - a form of free speech - rather than traditional goods or services.

In the dissenting opinion for the Associated Press v. United States case, it was argued that the majority's decision misinterpreted and overextended federal antitrust laws. The dissenters believed that news-gathering organizations should be allowed to set their own membership criteria without government interference as long as they do not engage in monopolistic practices or restrain trade. They contended that AP’s bylaws did not violate these principles because they merely restricted who could join and share in its services, rather than preventing non-members from competing with it or restricting market competition overall. Furthermore, they pointed out that applying antitrust laws to press associations might infrally upon First Amendment rights of freedom of speech and press since such associations are fundamentally different from commercial enterprises due to their role in disseminating information vital for democracy.