A convicted criminal may appeal his or her conviction and sentence to a higher court, known as an appellate court. The appellate court will review all or part of the written record of what transpired at the trial to determine whether any error prejudicial to the defendant was made. If any such error occurred, as where the trial court erred in its rulings on the admissibility of evidence or in its instructions to the jury on the law to be applied, the appellate court usually remands (returns) the case for a new trial. Sometimes, however, the error is of a type that leads to a reversal of conviction and the release of the defendant. For example, if the trial court incorrectly refused to declare unconstitutional the statute on which the prosecution was based, the appellate court would nullify the conviction, and the defendant would go free. In such a situation a new trial based on the unconstitutional statute is not permitted. If the appellate court finds no error or deems any errors harmless-that is, not substantial and not prejudicial to the interests of the defendant-it affirms the conviction.
