Are obscenities illegal under US law?

Obscenities are not inherently illegal under U.S. law; however, they can be subject to regulation based on context and community standards. The First Amendment protects free speech, including some forms of obscenity, but it does not protect "obscene" material that meets the criteria established by the Supreme Court in Miller v. California (1973). This ruling determined that obscene content, which lacks serious literary, artistic, political, or scientific value and appeals to prurient interests, can be restricted. Thus, while obscenities are generally permissible, certain obscene materials can be legally prohibited.