Jury nullification
Jury nullification occurs in a trial when a jury acquits a defendant, even though the members of the jury may believe that the defendant did the illegal act, yet they don't believe he or she should be punished for it. 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. A jury can similarly unjustly and illegally convict a defendant on the ground of disagreement with an existing law, even if no law is broken (although in jurisdictions with double jeopardy rules, a conviction can be overturned on appeal, but an acquittal cannot).
A jury verdict that is contrary to the letter of the law pertains only to the particular case before it. If a pattern of acquittals develops, however, in response to repeated attempts to prosecute a statutory offence, this can have the de facto effect of invalidating the statute. A pattern of jury nullification may indicate public opposition to an unwanted legislative enactment.
Jury Nullification (book)
Jury Nullification: The Evolution of a Doctrine, by Clay Conrad, is one of the major book-length treatments of jury nullification.The Federal Lawyer noted, "Conrad provides...a comprehensive overview of jury nullification in historical, substantive, policy, and practical terms." The book surveys the history of jury nullification, describing how it has changed with cases such as Sparf v. United States and with the advent of death-qualified juries. It ends with a chapter of advice for those pursuing a nullification-based defense.
