The Sixth Amendment guarantees the right to a trial by a jury but doesn't give details of the workings of the institution during a proceeding.

When can one get a trial by jury?

The Supreme Court answered this question with the landmark case Duncan v. Lousiana. The Duncan case incorporated the right to a jury trial to state criminal proceedings and to those where the punishment could lead to greater than six months in jail. The Supreme Court emphasized the six-month approach in U.S. v. Nachtigal in which a fine of $5,000 imposed without a jury was upheld as the individual was not in danger of being sentenced more than six months. The Supreme Court also clarified that multiple petty offenses do not garner a jury trial in Lewis v. U.S unless one of the offenses garners imprisonment greater than six months.

Size Of Juries

Traditionally, juries have been composed of 12 members. However, the Supreme Court reasoned in Williams v. Florida that a jury with six members is sufficient to garner a fair trial. The Supreme Supreme Court later set the minimum at six with Ballew v. Georgia in which a conviction based on a five-member jury violated the Sixth Amendment.

Unanimity Of Juries

The Supreme Court has determined in Apodaca v. Oregon that unanimous jury decisions are not required to convict criminals. In Johnson v. Lousiana, a law which allowed for convictions with nine out of 12 jurors was upheld. However, in Burch v . Louisiana, a law which allowed for convictions based on five out of six was not allowed as the intimacy of having such a low number of members required a unanimous agreement among the jurors.

Jury Selection

The Supreme Court in 1975 invalidated a Louisiana state law which excluded women from a jury pool. Thus, the Supreme Court has required that a pool of jurors must be a fair cross-section of the community. In Batson v. Kentucky, the Supreme Court determined that the removal of a juror based solely on race violated the Equal Protection Clause. The decision extended to gender in JEB v. Alabama.