In the case of Books, Inc. v. United States in 1966, the Supreme Court upheld a ruling that Books, Inc., a bookstore chain based in New York City, had violated antitrust laws by receiving discriminatory discounts from publishers and wholesalers not available to other booksellers. The court found that these practices were harmful to competition and thus constituted an unfair trade practice under the Robinson-Patman Act of 1936. This act prohibits any person or firm engaged in commerce from discriminating in price between different purchasers if it may substantially lessen competition or create monopoly power. Despite arguments made by Books Inc., claiming they were simply taking advantage of volume discounts which are allowed under certain conditions within the law, their appeal was rejected on grounds that such allowances did not apply due to evidence showing potential harm towards competitors who could not receive similar discounts.

In the dissenting opinion for Books, Inc. v. United States (1966), Justice William O. Douglas argued that the majority's decision was an overreach of federal power and a violation of First Amendment rights to free speech and press freedom. He contended that obscenity should not be determined by whether it appeals to prurient interests, but rather if it incites unlawful action or is patently offensive in its disregard for contemporary community standards. Furthermore, he believed that only hard-core pornography could be deemed obscene under these criteria - a category which did not include the material in question within this case according to him. Douglas also criticized the majority's reliance on expert testimony regarding societal harm caused by such materials as irrelevant; stating instead that potential harm cannot justify censorship unless there is clear evidence of imminent danger resulting from said material. Lastly, he expressed concern about giving too much discretion to judges and juries when determining what constitutes obscenity due their subjective nature leading potentially towards arbitrary enforcement thereby chilling free expression out of fear prosecution. Overall, his dissent emphasized protection against government intrusion into individual liberties especially those related with freedom of expression while cautioning against broad interpretations allowing excessive state control over content dissemination based on subjective moral judgments or speculative harms without concrete evidences thereof causing immediate threats public safety order etcetera