Which Supreme Court case established that obscenity is not protected under the First Amendment?

The Supreme Court case that established that obscenity is not protected under the First Amendment is Miller v. California. This landmark decision, made in 1973, focused on the definition of obscenity and set out a three-part test for determining whether material is obscene and thus not entitled to First Amendment protection. The ruling emphasized the need for a community standards approach, meaning that what might be considered obscene could vary from one community to another.

The Miller test involves assessing whether the average person, applying contemporary community standards, would find that the work, taken as a whole, appeals to the prurient interest; whether the work depicts or describes, in a patently offensive way, sexual conduct specifically defined by applicable state law; and whether the work, taken as a whole, lacks serious literary, artistic, political, or scientific value. This decision underscored the balance the Court sought to strike between protecting free speech while also addressing community concerns about obscenity, clearly differentiating it from other forms of speech that enjoy First Amendment protections.