The First Amendment protects five fundamental freedoms that lie at the heart of American civil liberties. It begins with two Religion Clauses: the Establishment Clause, which prohibits the government from establishing an official religion or unduly favoring one religion over another, and the Free Exercise Clause, which protects individuals' right to practice their religion freely. The amendment also protects the freedoms of speech, of the press, of peaceable assembly, and the right to petition the government for redress of grievances. The Free Speech Clause, in particular, has produced a vast body of case law. Although most expression is protected, certain categories of speech receive no constitutional protection, including obscenity, fighting words, true threats, incitement to imminent lawless action, child pornography, and fraud.
The Supreme Court has defined the boundaries of First Amendment rights through several landmark decisions. In Schenck v. United States (1919), Justice Oliver Wendell Holmes articulated the "clear and present danger" test, allowing restriction of speech that creates imminent harm. Brandenburg v. Ohio (1969) later replaced this with a stricter standard, holding that the government cannot punish inflammatory speech unless it is directed to inciting imminent lawless action and is likely to produce such action. In Tinker v. Des Moines (1969), the Court ruled that students do not shed their constitutional rights at the schoolhouse gate, protecting the wearing of armbands as symbolic speech. New York Times v. Sullivan (1964) required public officials suing for defamation to prove actual malice, raising the bar for protecting political criticism. Texas v. Johnson (1989) held that flag burning constitutes protected symbolic speech, and Citizens United v. FEC (2010) extended First Amendment protection to independent political expenditures by corporations and unions. Establishment Clause cases, such as Lemon v. Kurtzman (1971), established the Lemon test requiring government actions to have a secular purpose, neither advance nor inhibit religion, and avoid excessive entanglement with religion, while Engel v. Vitale (1962) banned school-sponsored prayer in public schools.
The Second Amendment protects the right to keep and bear arms. In District of Columbia v. Heller (2008), the Supreme Court held that this amendment protects an individual's right to possess firearms for lawful purposes, unconnected with militia service. McDonald v. City of Chicago (2010) then incorporated this right against state and local governments through the Fourteenth Amendment's Due Process Clause. The Third Amendment, one of the least litigated provisions, prohibits the quartering of soldiers in private homes without the owner's consent during peacetime. The Fourth Amendment protects against unreasonable searches and seizures, requiring that warrants be issued only upon probable cause and particularly describing the place to be searched. In Mapp v. Ohio (1961), the Court applied the exclusionary rule to state courts, barring the use of evidence obtained in violation of the Fourth Amendment.
The Fifth, Sixth, Seventh, and Eighth Amendments provide crucial protections in the criminal justice system. The Fifth Amendment requires grand jury indictments for serious crimes, prohibits double jeopardy, protects against self-incrimination, guarantees due process of law, and requires just compensation when the government takes private property. The Sixth Amendment guarantees the right to a speedy and public trial by an impartial jury, the right to be informed of charges, the right to confront witnesses, the right to compulsory process, and the right to the assistance of counsel. The Court held in Gideon v. Wainwright (1963) that states must provide counsel to criminal defendants who cannot afford an attorney, and in Miranda v. Arizona (1966), the Court required that suspects be informed of their right to remain silent and to an attorney before custodial interrogation, giving rise to the famous "Miranda rights." The Seventh Amendment preserves the right to a jury trial in civil cases where the value in controversy exceeds twenty dollars, while the Eighth Amendment prohibits excessive bail, excessive fines, and cruel and unusual punishment, including limiting the death penalty for intellectually disabled persons and juveniles. The Ninth Amendment notes that the enumeration of certain rights shall not be construed to deny others retained by the people, and the Tenth Amendment reserves powers not delegated to the federal government to the states or the people.