https://en.wikipedia.org/wiki/Jury_nullification
Jury nullification is a concept where members of a trial jury can vote a defendant not guilty if they do not support a government's law, do not believe it is constitutional or humane, or do not support a possible punishment for breaking a government's law. This may happen in both civil and criminal trials. In a criminal trial, a jury nullifies by acquitting a defendant, even though the members of the jury may believe that the defendant did the act the government considers illegal. This may occur when members of the jury disagree with the law the defendant has been charged with breaking, or believe that the law should not be applied in that particular case.