What does the First Amendment actually protect?

The First Amendment prohibits the government from establishing religion or prohibiting its free exercise, and from abridging freedom of speech, freedom of the press, the right to assemble peaceably, and the right to petition the government. Its constraint runs against government actors at federal, state, and local levels, applied to the states through the Fourteenth Amendment. That is the source of the most common misunderstanding: a private employer disciplining an employee for speech, a social platform removing a post, a publisher declining a manuscript, or a venue cancelling a booking are private decisions, and the Constitution does not reach them. Those may raise questions about fairness or policy, but they are not constitutional questions.

Protection is also not unlimited against the government. Established categories receiving little or no protection include incitement to imminent lawless action under the Brandenburg standard, true threats, defamation, obscenity as narrowly defined, fraud, speech integral to criminal conduct, and child sexual abuse material. Content-neutral restrictions on the time, place, and manner of expression are permitted if narrowly tailored and leaving open adequate alternatives, which is how permit requirements for demonstrations survive. Government employers, schools, and the military operate under distinct and more permissive standards regarding their own personnel and students.

What is protected is broader than many assume, and deliberately so. Political speech receives the strongest protection, including speech that is offensive, hateful, or false, since American doctrine does not recognize a general hate speech exception, which distinguishes the United States from most other democracies. Symbolic expression including flag burning is protected. The related right not to speak is protected, which is why compelled speech cases arise. And the press clause protects the act of publishing rather than a credentialed profession, which matters as newsgathering shifts to independent and online publishers.