The First Amendment’s declaration that “Congress shall make no law…abridging the freedom of speech” establishes a broad shield against government censorship. This protection covers not just popular ideas, but also speech that is offensive or disagreeable to the majority. The core principle is the “marketplace of ideas,” a theory that the best way to combat bad ideas is with more speech and open debate, not suppression.
This constitutional protection applies specifically to government actions. It does not prevent private entities, like social media companies or employers, from setting their own rules for acceptable speech.