The Sixth Amendment to the United States Constitution guarantees that “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 wherein the crime shall have been committed, which district shall have been previously ascertained by law.” The Sixth Amendment goes on to preserve other rights for criminal defendants, but says nothing else about what a “trial by an impartial jury” entails.
The United States Supreme Court has held that the Sixth Amendment right to a jury trial—which also applies to the states by way of the Fourteenth Amendment—requires a unanimous verdict to convict a defendant of a serious offense in state or federal court. A serious offense is generally a felony offense, or a misdemeanor in which the defendant may be sentenced to a year or more in jail or prison.
