The scheme of American jurisprudence wherein a judge or jury renders a decision in a controversy between or among parties who assert contradictory positions during a judicial examination such as a trial, hearing, or other adjudication.
U.S. courtrooms have often been compared to battlefields or playing fields. The adversary system by which legal disputes are settled in the United States promotes the idea that legal controversies are battles or contests to be fought and won using all available resources.
The contemporary Anglo-American adversary system has gradually evolved, over several hundred years. Early English jury trials were unstructured proceedings in which the judge might act as inquisitor, or even prosecutor, as well as fact finder. Criminal defendants were not allowed to have counsel, to call witnesses, to conduct cross-examination, or to offer affirmative defenses. All types of evidence were allowed, and juries, although supposedly neutral and passive, were actually highly influenced by the judge's remarks and instructions. In fact, before 1670, jurors could be fined or jailed for refusing to follow a judge's directions.
The late 1600s saw the advent of a more modern adversarial system in England and its American colonies. Juries took a more neutral stance, and appellate review, previously unavailable, became possible in some cases. By the eighteenth century, juries assumed an even more autonomous position as they began functioning as a restraint on governmental and judicial abuse and corruption. The Framers of the Constitution recognized the importance of the jury trial in a free society by specifically establishing it in the Sixth Amendment as a right in criminal prosecutions. The Eight Amendment also established the right to a jury in noncriminal cases:"In Suits at common law, where the value in controversy shall exceed twenty dollars, the right of trial by jury shall be preserved, and no fact tried