In the 1961 case of Manual Enterprises, Inc. v. Day, the U.S. Supreme Court ruled in favor of three publishers who were accused by Postmaster General J. Edward Day of distributing obscene material through the mail system which was prohibited under federal law at that time (18 U.S.C.A §1461). The publications in question contained photographs and drawings of male nudes intended for a homosexual audience but did not depict sexual activity or arousal explicitly. The court held that these materials could not be classified as "obscene" within the meaning of §1461 because they were not inherently “erotic” or “pornographic.” The majority opinion stated that while some may find such content distasteful or offensive due to personal moral views, it does not necessarily make them legally obscene. This ruling marked an important shift towards protecting freedom of speech and press rights under First Amendment from overbroad interpretations and applications of obscenity laws.

In the dissenting opinion for Manual Enterprises, Inc. v. Day, Justice Harlan argued that the majority's decision to allow certain male physique magazines to be mailed was incorrect because it failed to properly interpret and apply obscenity laws. He believed that these materials were indeed obscene as they catered primarily to a homosexual audience with prurient interests, which he considered outside of societal norms at the time. Furthermore, he contended that allowing such material could lead down a slippery slope where more explicit content might also have to be permitted under similar reasoning in future cases. Thus, according to him, this ruling undermined efforts by Congress and other authorities trying hard over years towards maintaining public morality through censorship of sexually suggestive or explicit materials.