All ideas having even the slightest redeeming social importance—unorthodox ideas, controversial ideas, even ideas hateful to the prevailing climate of opinion—have the full protection of the guaranties…. But implicit in the history of the First Amendment is the rejection of obscenity as utterly without redeeming social importance.

This line comes from Justice William J. Brennan Jr.’s majority opinion for the U.S. Supreme Court in Roth v. United States (1957), a landmark First Amendment case testing federal and state obscenity laws. The Court reaffirmed that the First Amendment broadly protects speech, including unpopular or offensive ideas, but drew a categorical boundary around “obscenity,” which it treated as outside constitutional protection. Brennan’s formulation reflects the mid‑20th‑century effort to reconcile expanding free-speech doctrine with long-standing moral regulation of sexually explicit materials, and it helped set the framework that later cases (notably Miller v. California) would revise and refine.

Brennan contrasts two categories: (1) “ideas,” even those widely despised, which the First Amendment protects because they can contribute to public discourse; and (2) “obscenity,” which he characterizes as lacking any “redeeming social importance” and therefore not part of the Amendment’s core purpose. The passage reveals a key doctrinal move: protection turns not on whether speech is offensive, but on whether it is considered expressive of ideas with social value. At the same time, the quote exposes a vulnerability in the approach—who decides what counts as “redeeming” value—an issue that later jurisprudence grappled with by adopting more detailed tests and, eventually, by Brennan himself expressing doubts about administrable obscenity standards.