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. Criticism of the government and advocation of unpopular ideas that people may find distasteful or against public policy, such as racism, are generally permitted. There are exceptions to the general protection of speech, however, including the Miller test for obscenity, child pornography laws, and regulation of commercial speech such as advertising. Other limitations on free speech often balance rights to free speech and other rights, such as property rights for authors and inventors (copyright), interests in fair political campaigns (Campaign finance laws), protection from imminent or potential violence against particular p