Also known as jury lenity.
In US v Desmond, Justice Weis of the United States Court of Appeals wrote this on this rare, rarely invoked extraordinary prerogative:
"The doctrine of jury nullification (is) the power of a jury to bring in a verdict in the teeth of both law and facts, a technical right, if it can be called so, to decide against the law and the facts.
"Jury nullification has a unique place in the law and has been the subject of spirited debate for hundreds of years in both English and American law.... Yet, when defendants have asked that jurors be instructed on their power of nullification, the requests have been denied. Thus, although acknowledging the existence of the jury's prerogative and its beneficial role in acting as a safety valve, the courts do not encourage exercise of the right. Fear of excess or intolerable caprice is cited as the reason."
In R v Latimer, Canada's Supreme Court opined:
"The term jury nullification refers to that rare situation where a jury knowingly chooses not to apply the law and acquits a defendant regardless of the strength of the evidence against him. Jury nullification is an unusual concept within the criminal law, since it effectively acknowledges that it may occur that the jury elects in the rarest of cases not to apply the law. The explanation seems to be that on some occasions, oppression will result either from a harsh law or from a harsh application of a law.
"This Court has referred to the jury’s power to nullify as the citizen’s ultimate protection against oppressive laws and the oppressive enforcement of the law” and it has characterized the jury nullification power as a safety valve for exceptional cases.... [H]owever, ... recognizing this reality that a jury may nullify is a far cry from suggesting that counsel may encourage a jury to ignore a law they do not support or to tell a jury that it has a right to do so....
"As a matter of logic and principle, the law cannot encourage jury nullification."
Justice McKenzie of the British Columbia Court of Appeals, in R v Budai, at ¶78, called jury nullification:
"... a bedrock feature of our system of criminal justice."
In US v Scarmazzo, Justice Oliver Wanger of the United States District Court adopted these words in a medicinal marijuana prosecution case:
"Jury nullification is the de facto ability of the jury to refuse to apply the law as instructed by the court, choosing instead to acquit out of compassion or compromise or because of the jury's assumption of a power which they had no right to exercise, but to which they were disposed through lenity."
In State v Hook, Justice Kevin Ross of the Court of Appeals of Minnesota wrote:
"Jury nullification, also called jury lenity, is the extraordinary power of the jury to issue a not-guilty verdict even if the law as applied to the proven facts establishes that the defendant is guilty.
"Jury nullification is a curious paradox: it is the jury's prerogative to disregard the law without actually committing an unlawful offense in doing so; its exercise is literally illegitimate (contrary to law) but practically legitimate (allowed by law). It is the physical power to disregard the law that has been laid down to the jury by the court. In that sense, the most accurate description of the jury's paradoxical authority to act on its own in disregard of the law even while it is charged with following the law is the raw power to bring in a verdict of acquittal in the teeth of the law and the facts."
In State of Louisiana v Chatman, Justice John Lolley of the Court of Appeal of Louisiana wrote:
"Jury nullification is a recognized practice which allows the jury to disregard uncontradicted evidence and instructions by the trial court."