Jury nullification is what happens when a criminal jury returns a “not guilty” verdict even though the jurors believe the prosecution proved the defendant broke the law. The jury sets the statute aside, usually because they think the law itself is unjust or the punishment does not fit what the defendant actually did. Every criminal jury has the raw power to do this, but no judge will ever tell them so, and the entire architecture of a criminal trial is built to keep the idea from surfacing.
Why the Power Exists at All
Nullification is possible because of two rules that no court has ever undone. Jurors cannot be punished for their verdict, and an acquittal in a criminal case cannot be reversed. Take those two rules together and a jury that decides to acquit for any reason at all, including a reason the law does not recognize, will get away with it.
The rule against punishing jurors traces to a 1670 English case. A jury acquitted William Penn of unlawful assembly for preaching his Quaker faith, and the judge fined and jailed the jurors in response. One of them, Edward Bushell, challenged the punishment. Chief Justice Vaughan sided with him and held that jurors could not be fined or imprisoned for their verdicts no matter how sharply those verdicts departed from the evidence or the court’s instructions. That principle has never been reversed. It is the reason a modern juror can vote to acquit for any reason they choose and walk out of the courthouse with no consequences.
A Power, Not a Right
The Supreme Court has drawn a careful line around nullification. In Sparf v. United States (1895), the Court held that it is “the duty of the jury, in criminal cases, to receive the law from the court, and to apply it as given by the court.” The Court acknowledged that a general verdict of acquittal necessarily means the jury “determines both law and fact,” but concluded that the reality does not entitle jurors to be told they can judge the law.1Justia U.S. Supreme Court Center. Sparf and Hansen v United States, 156 US 51
So nullification is a power the system cannot eliminate but refuses to endorse. Jurors take an oath to decide the case on the law and the evidence. Federal model instructions put it flatly: “You must follow the law as I give it to you whether you agree with it or not.”2Ninth Circuit District & Bankruptcy Courts. 1.4 Duty of Jury A juror who nullifies is acting against that oath. Courts accept the tension without resolving it because there is no way to resolve it without dismantling the acquittal itself.
What Actually Has to Happen in the Jury Room
For nullification to produce an acquittal, every juror has to agree. That is not a small requirement, and it is where a lot of confusion sits.
Deliberations are secret by law. Federal Rule of Evidence 606(b) bars jurors from testifying about statements made or incidents that occurred during deliberations and prevents courts from receiving juror affidavits about those discussions.3Legal Information Institute. Rule 606 – Jurors Competency as a Witness Nobody outside the room ever learns whether a verdict rested on doubts about the evidence, a moral objection to the law, or some mix of the two. That secrecy is what makes nullification practically possible. A juror can raise the idea, the group can talk through it, and if they all agree the foreperson simply announces “not guilty.” No one labels it. It looks identical to any other acquittal.
Hung Jury Is Not Nullification
If some jurors want to nullify but cannot bring the others along, the result is a hung jury and a mistrial, not an acquittal. The distinction matters enormously. A mistrial lets the prosecution try the case again with a fresh jury. Only a unanimous “not guilty” ends the case for good. A single juror acting on conscience can stall a conviction but cannot deliver nullification alone.
What a Nullification Acquittal Protects You From
Once the jury announces “not guilty,” the verdict is as final as any other acquittal. The Double Jeopardy Clause of the Fifth Amendment stops the government from retrying a person for the same offense after an acquittal, a rule the Supreme Court has called “the most fundamental rule in the history of double jeopardy jurisprudence.”4Congress.gov. Constitution Annotated – Overview of Re-Prosecution After Acquittal The prosecution cannot appeal. No judge can set the verdict aside. The jurors themselves face no legal consequences.
There is one important limit. The dual sovereignty doctrine means an acquittal in state court does not stop the federal government from prosecuting the same conduct under a separate federal statute, and vice versa. The Supreme Court reaffirmed that principle in Gamble v. United States in 2019. A state jury that nullifies a drug charge does not shield the defendant from a federal drug prosecution based on the same events. Separate sovereigns, separate cases.
Why Nullification Only Exists in Criminal Trials
Civil juries cannot nullify in any meaningful sense. If a judge in a civil case believes the jury reached a verdict no reasonable person could support on the evidence, the judge can grant a directed verdict or enter judgment as a matter of law, overriding the jury outright. That override closes the structural gap. In criminal cases the gap stays open because a judge cannot touch an acquittal. Nullification lives in that gap and nowhere else.
How Courts Work to Keep Nullification From Happening
Because the system cannot punish nullification after the fact, it invests heavily in preventing it. Three stages of the trial do that work.
Jury Selection
Voir dire is the first filter. Prosecutors routinely ask prospective jurors whether they can follow the law the judge gives them even if they personally disagree with it. Any hesitation or expressed reservation about a particular statute is grounds to challenge and remove that person. Defense attorneys cannot use voir dire to plant the idea of nullification either. The goal is a jury that has committed, on the record, to acting as fact-finders rather than law-evaluators.
Instructions and Attorney Restrictions
Judges tell every jury that their job is to apply the law to the facts. The standard federal instruction is direct: “You must decide the case solely on the evidence before you. You will recall that you took an oath to do so.”5Ninth Circuit District & Bankruptcy Courts. 6.1 Duties of Jury to Find Facts and Follow Law Defense lawyers are prohibited from arguing for nullification or suggesting the jury ignore the law. An attorney who tells a jury they can acquit despite the evidence risks sanctions or a mistrial. A defendant representing themselves is bound by the same restriction.
Removing a Juror Mid-Trial
If a judge suspects a sitting juror plans to nullify, the judge can investigate and potentially dismiss that juror. The standard for doing so is deliberately high. In United States v. Thomas (1997), the Second Circuit held that a juror may be removed for refusing to follow instructions “only where the record is clear beyond doubt that the juror is not, in fact, simply unpersuaded by the prosecution’s case.”6Justia. United States v Thomas, 116 F3d 606 The court reversed a dismissal because the trial record left open the possibility that the juror simply doubted the government’s proof. That high bar exists because the secrecy of deliberations and the protection of unpopular but honest verdicts both matter to the system.
The Risk of Advocating for Nullification
Talking about jury nullification as a general concept is protected speech. Trying to steer a specific jury toward nullifying a specific case is a crime, and the line is sharper than most people expect.
Federal law makes it an offense to attempt to influence a juror’s decision by sending or giving them any written communication about a pending case, punishable by a fine, up to six months in prison, or both.7Office of the Law Revision Counsel. 18 USC 1504 – Influencing Juror by Writing A broader obstruction statute reaches anyone who “corruptly… endeavors to influence, intimidate, or impede” any juror in the discharge of their duty, with penalties up to ten years.8Office of the Law Revision Counsel. 18 USC 1503 – Influencing or Injuring Officer or Juror Generally
Where general advocacy ends and jury tampering begins was tested in United States v. Heicklen, where a man was indicted for distributing jury nullification pamphlets on the sidewalk in front of a federal courthouse. The judge dismissed the case, holding that the jury tampering statute reaches written communications “aimed at influencing a specific juror’s vote in a particular case.” Handing literature to pedestrians in the hope some might turn out to be jurors did not qualify. Educating the public about nullification is legal. Identifying jurors in a pending case and mailing them nullification material is a federal crime, no matter the intent behind it.