Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
Despite the broad freedom of expression guaranteed by the First Amendment, there are some historically rooted exceptions. First, the government may generally restrict the time, place, or manner of speech, if the restrictions are unrelated to what the speech says and leave people with enough alternative ways of expressing their views. Thus, for instance, the government may restrict the use of loudspeakers in residential areas at night, limit all demonstrations that block traffic, or ban all picketing of people’s homes.
Second, a few narrow categories of speech are not protected from government restrictions. The main such categories are incitement, defamation, fraud, obscenity, child pornography, fighting words, and threats. As the Supreme Court held in Brandenburg v. Ohio (1969), the government may forbid “incitement”—speech “directed at inciting or producing imminent lawless action” and “likely to incite or produce such action” (such as a speech to a mob urging it to attack a nearby building). But speech urging action at some unspecified future time may not be forbidden.
Defamatory lies (which are called “libel” if written and “slander” if spoken), lying under oath, and fraud may also be punished. In some instances, even negligent factual errors may lead to lawsuits. Such exceptions, however, extend only to factual falsehoods; expression of opinion may not be punished even if the opinion is broadly seen as morally wrong.
Certain types of hard-core pornography, labeled obscenity by the law, may also be punished, as the Supreme Court held in Miller v. California (1973). Exactly what constitutes obscenity is not clear, but since the 1980s the definition has been quite narrow. Also, obscenities in the sense of merely vulgar words may not be punished (Cohen v. California ).
Material depicting actual children engaging in sex, or being naked in a sexually suggestive context, is called child pornography and may be punished. Sexually themed material that uses adults who look like children or features hand-drawn or computer-generated pictures of fictional children does not fall within this exception, though some such material might still be punishable as obscenity.
Fighting words—defined as insults of the kind likely to provoke a physical fight—may also be punished, though general commentary on political, religious, or social matters may not be punished, even if some people are so upset by it that they want to attack the speaker. Personalized threats of illegal conduct, such as death threats, may also be punished.
No exception exists for so-called hate speech (see also hate crime). Racist threats are unprotected by the First Amendment alongside other threats, and personally addressed racist insults might be punishable alongside other fighting words. But such speech may not be specially punished because it is racist, sexist, antigay, or hostile to some religion.