The First Amendment of the U.S. Constitution states:
The purpose of the free speech was to limit the power of the federal government. For James Madison, "the First Amendment is not about self-expression, the search for truth as an end in itself, or even the opportunity for political participation as a means of self-fulfillment — it is about checking abuses of power." The First Amendment was only mentioned in passing in his objections to the Sedition Act of 1798.[1]
After the Civil War and the passage of the Fourteenth Amendment, the U.S. Supreme Court expanded the First Amendment to apply against all forms of government, such as state and local governments.
Free speech is the doctrine that allows a citizen to speak freely without government restriction.
Supreme Court Justice Louis D. Brandeis wrote in Whitney v. California, 274 U.S. 357 (1927):
An important distinction is that free speech is not the right to be able to speak freely in a private setting such as a job or a school. You can be fired for criticizing your company's product in front of a customer, insulting your boss, etc. While the government may not intrude, private organizations may set their own speech policies, and every citizen has a duty to speak and act responsibly. The First Amendment addresses none of these concerns as protected.
Speech that is termed "fighting words" is not protected speech. That is to say that speech that causes an act which the law does not protect, is not protected. Thus, it is not a free speech violation to arrest a person for shouting "Fire!" in a crowded theater when there is no fire. Similarly, it is not protected speech to advocate the death of the president.
Heckling is a gray area in the ethics of free speech. To a certain extent, interrupting a public speech with question or retorts is tolerated. On the other hand, using heckling as a tactic to stop the speaker is not an expression of free speech (on the heckler's part) as much as it is a violation of the speaker's free speech rights.
Also, according to conservative judge William Rehnquist, free speech does not include the right to burn the American flag.
Christians believe its basis is the Christian evangelism that characterized the American colonies in the period leading up to the American Revolution. Of all the nations of the world, the one which provides the most support for free speech is the United States (see Marketplace of ideas).
Others point to the history of political & patriotic dissent as an American tradition, and the last wall against tyranny.
The jury acquittal of John Peter Zenger (1735) in the colony of New York played an important early role in expanding freedom of press and free speech.