Freedom of speech in the United States is protected by the First Amendment to the United States Constitution and by many state constitutions and state and federal laws. The freedom of speech is not absolute; the Supreme Court of the United States has recognized several categories of speech that are excluded from the freedom, and it has recognized that governments may enact reasonable time, place, or manner restrictions on speech. Criticism of the government and advocacy of unpopular ideas that people may find distasteful or against public policy are almost always permitted. There are exceptions to these general protections, including the Miller test for obscenity, child pornography laws, speech that incites imminent lawless action, and regulation of commercial speech such as advertising. Within these limited areas, other limitations on free speech balance rights to free speech and other rights, such as rights for authors over their works (copyright), protection from imminent or potential violence against particular persons (restrictions on fighting words), or the use of untruths to harm others (slander). Distinctions are often made between speech and other acts which may have symbolic significance. Despite the exceptions, the legal protections of the First Amendment are some of the broadest of any industrialized nation, and remain a critical, and occasionally controversial, component of American jurisprudence.