In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the State and district where in the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor, and to have the Assistance of Counsel for his defense.
If the reviewing court finds that a defendant's right to a speedy trial was violated, then the indictment must be dismissed and/or the conviction overturned. The Supreme Court has held that, since the delayed trial itself is the state action which violates the defendant's rights, no other remedy would be appropriate. Thus, a reversal or dismissal of a criminal case on speedy trial grounds means that no further prosecution for the alleged offense can take place.
Originally, the Supreme Court held that the Sixth Amendment right to a jury trial indicated a right to “a trial by jury as understood and applied at common law, and includes all the essential elements as they were recognized in this country and England when the Constitution was adopted.” Therefore, it was held that juries had to be composed of twelve persons and that verdicts had to be unanimous, as was customary in England. When, under the Fourteenth Amendment, the Supreme Court extended the right to a trial by jury to defendants in state courts, it re-examined some of the standards. It has been held that the twelve came to be the number of jurors by "historical accident," and that a jury of six would be sufficient but anything less would deprive the defendant of a right to trial by jury. Although on the basis of history and precedent the Sixth Amendment mandates unanimity in a federal jury trial, the Supreme Court has ruled that the Due Process Clause of the Fourteenth Amendment, while requiring States to provide jury trials for serious crimes, does not incorporate all the elements of a jury trial within the meaning of the Sixth Amendment and does not require jury unanimity.
Juries must be, by the terms of the Sixth Amendment, impartial. Firstly, the phrase has been interpreted as requiring individual jurors to be unbiased. At voir dire, each side may question potential jurors to determine any bias, and challenge them if the same is found; the court determines the validity of these challenges for cause. The defendant may not challenge a conviction, however, on the grounds that a challenge for cause was denied incorrectly if the defendant had the opportunity to use peremptory challenges.
Another factor in determining the impartiality of the jury is the nature of the panel, or venire, from which the jurors are selected. Venires must represent a fair cross-section of the community; the defendant may establish that the requirement was violated by showing that the allegedly excluded group is a "distinctive" one in the community, that the representation of such a group in venires is unreasonable and unfair in regard to the number of persons belonging to such a group and that the under-representation is caused by a systematic exclusion in the selection process. Thus, in Taylor v. Louisiana, , the Supreme Court invalidated a state law that exempted women who had not made a declaration of willingness to serve from jury service, while not doing the same for men.
The Constitution originally required that defendants be tried by juries selected from the state in which the crime was committed. The Sixth Amendment extends the rule by requiring trials to occur in districts ascertained by statute. As the Supreme Court found in Beavers v. Henkel, , the place where the offense is charged to have occurred determines the trial's location. Where multiple districts are alleged to have been locations of the crime, any of them may be chosen for the trial. In cases of offenses not committed in any state (for example, offenses committed at sea), the place of trial may be determined by Congress.
The defendant must also be permitted to call witnesses in his/her favor. If such witnesses refuse to attend, they may be compelled to do so by the court at the request of the defendant. In some cases, however, the court may refuse to permit a defense witness to testify. If, for example, a defense lawyer fails to notify the prosecution of the identity of its witnesses in order to gain a tactical advantage, the witnesses whose identities were undisclosed may be precluded from testifying.
The right to confront and cross-examine witnesses also applies to physical evidence; the prosecution must present physical evidence to the jury, providing the defense ample opportunity to cross-examine its validity and meaning. Prosecution generally may not refer to evidence without first presenting it.
Originally, the clause was not interpreted as requiring the state to appoint counsel where the defendant could not afford to do so. The Supreme Court began to expand the interpretation of the clause in Powell v. Alabama, , in which it held, “in a capital case, where the defendant is unable to employ counsel, and is incapable adequately of making his own defense because of ignorance, feeble mindedness, illiteracy, or the like, it is the duty of the court, whether requested or not, to assign counsel for him.” In Johnson v. Zerbst, , the Supreme Court ruled that in all federal cases, counsel would have to be appointed for defendants who were too poor to hire their own. When deciding Betts v. Brady, , the Court declined to extend this requirement to the state courts under the Fourteenth Amendment unless the defendant demonstrated "special circumstances" requiring the assistance of counsel.
In 1960, the Court extended the rule that applied in federal courts to state courts. It held in Hamilton v. Alabama, that counsel had to be provided at no expense to defendants in capital cases when they so requested, even if there was no "ignorance, feeble mindedness, illiteracy, or the like." Gideon v. Wainwright, explicitly overruled Betts v. Brady, finding counsel must be provided to indigent defendants in all felony cases, whether capital or otherwise. Argersinger v. Hamlin, and Scott v. Illinois, expanded the right further, guaranteeing counsel in any charge resulting in a sentence of actual imprisonment.
As stated in Brewer v. Williams, , the rights granted by Sixth and Fourteenth Amendments “mean at least that a person is entitled to the help of a lawyer at or after the time that judicial proceedings have been initiated against him, whether by formal charge, preliminary hearing, indictment, information, or arraignment.” 430 U.S. at 398. Brewer goes on to conclude that once adversary proceeding have begun against a defendant, he has a right to legal representation when the government interrogates him 430 U.S. at 401, citing Massiah v. United States, and that when a defendant is arrested, “arraigned on [an arrest] warrant before a judge,” and “committed by the court to confinement,” “[t]here can be no doubt . that judicial proceedings ha[ve] been initiated.”
The circuit courts have narrowed the right to exclude appeal procedures as in Martinez v. California Court of Appeals 528 U.S. 152, 163 (2000), and again by reference in US v. Moussaoui (4th Cir. 2003) (No. 03-4162); however, this restriction is new, inconsistent with precedent, and has yet to be tested in the Supreme Court.