The First Amendment of the United States Constitution prohibits government interference in the rights toÂ freedom of religion and expression. Freedom of expression covers the freedoms of speech, the press, the right to assembly and the right to petition the government.
Freedom of religion is protected by the "separation of church and state" clause, which prevents any one religion from becoming the state's official religion to the detriment of others.
Freedom of speech underpins the First Amendment, but is not entirely without limitations. The government can lawfully interfere if they have grounds to, and such grounds might include potential breach of the peace by the use of hate speech, obscenity or advocating crime. The same rules apply to the press, who are granted no special dispensation.
The right to assemble only extends to peaceful and lawful assemblies. The government can legally require that any assembly with criminal intent disperse. Related to this is the right to petition the government for policy change, as it is lawful to assemble for this reason.
The converse implication of the First Amendment is that, in addition to freedom of speech and expression, U.S. citizens cannot be compelled to say or express anything in particular, or to associate with certain groups.