Jury nullification occurs when a jury returns a verdict of "Not Guilty" despite its belief that the defendant is guilty of the violation charged. The jury in effect nullifies a law that it believes is either immoral or wrongly applied to the defendant whose fate that are charged with deciding.
Once a jury returns a verdict of "Not Guilty," that verdict cannot be questioned by any court and the Double Jeopardy Clause of the U.S. Constitution prohibits a retrial on the same charge. In most jurisdictions, judges instruct jurors that it is their duty to apply the law as it is given to them, whether they agree with the law or not. In only a few states are jurors told that they have the power to judge both the facts and the law of the case. Most judges also will prohibit attorneys from using their closing arguments to directly appeal to jurors to nullify the law.
