Has a case ever been thrown out in the United States by a judge or on
appeal because of "jury nullification?" If so, what were the
What Is Jury Nullification In A Narrow Sense?
In a criminal case, once a jury has rendered a "not guilty" verdict (excluding extremely marginal cases where, for example, the jury accidentally filled in the wrong jury form and hasn't yet left the courthouse, or some form of extreme jury tampering such as bribery or extortion is discovered after the fact), this decision cannot be appealed or overturned by a judge, even if the "not guilty" verdict was knowingly reached for reasons contrary to the law.
Jury nullification, in the narrow sense of the word, refers to cases where a jury reaches a "not guilty" verdict that was knowingly reached for reasons contrary to the law as opposed to merely because they misunderstood their instructions.
Jury nullification in a narrow sense is never thrown out by a judge or on appeal, because a judge does not have the power to do so and there is no appeal from a "not guilty" verdict.
What Is Jury Nullification In A Broad Sense?
Guilty verdicts of juries in criminal cases, and any verdict in a civil case like a patent law case, are subject to post-trial review by the trial judge who can throw out the verdict or call for a new trial for a variety of reasons, and to appeal.
With the very narrow, newly created exception for guilty verdicts in criminal cases reached based upon racial or other kinds of impermissible prejudice rather than the facts of the case (or cases where there is an outside influence on the jury such as a bribe or someone looking up facts or law on the Internet), no one can challenge a jury verdict based upon the reasoning and conclusions actually made by the jurors, even if someone learns that the jury knowingly or accidentally didn't follow the law or was mistaken about the facts.
Instead, a judge or appellate court can only overturn a jury verdict* if:
The judge gave instructions about the law to the jury that were inaccurate and could have plausibly lead to an incorrect verdict if followed (This is a common reason for a reversal of a jury verdict on appeal.); or
The judge may rulings about how the trial should be conducted that hurt the side of the case that didn't get what they wanted in a way that could have plausibly lead to an incorrect verdict (This is a common reason for a reversal of a jury verdict on appeal.); or
There were irregularities in how the trial proceeded that were no one's fault that could have plausibly lead to an incorrect verdict (This is extremely rare - a typical trial in this category would be a trial that was interrupted by a hurricane or an earthquake.); or
The jury verdict has inconsistencies on its face that couldn't possibly be correct if the jury correctly applied the law to the facts in any reasonable manner such as awarding damages after ruling that a defendant is not liable (This happens extremely rarely); or
No evidence was presented at trial that could have permitted the jury to reach the result that it did (This kind of reversal of a jury verdict on appeal or by the judge after a trial, is fairly common.).
- CAVEAT: These reasons are necessary, but not sufficient reasons to overturn a jury verdict for reasons #1, #2 or #3. In those cases it is also necessary for the party that wants to overturn the verdict to "preserve" an objection to the jury instruction in question or the judge's reason, or the condition beyond the control of the parties or the court, in order to have a judge overturn the verdict or to prevail on appeal. Also, when I say that something could "plausibly" have resulted in a different verdict for reasons #1, #2 or #3, I am paraphrasing what is known as the "harmless error" rule which says that a verdict will not be reversed based upon mistake which was "harmless error."
The key thing to observe is that jury verdicts are almost always overturned, either based upon things that hypothetically could have caused them to reach an incorrect verdict (for the reasons I've labeled #1, #2 or #3) whether or not those mistakes actually caused the jury to reach the wrong verdict, or because under the circumstances it was impossible for the jury to have reached the verdict that it did (for the reasons I've labeled as #4 and #5).
Reversals of jury verdicts for reasons #1, #2 and #3 are not infrequently "false positive" where a verdict was overturned even though the reason for overturning it didn't actually influence the jury's verdict.
Almost all verdicts overturned for reasons #4 and #5 are "true positives" where the jury reached an incorrect result.
But, there are lots of jury verdicts which can't be overturned for any of the reasons #1, #2, #3, #4 or #5, even though the verdicts were actually based upon a misunderstanding of the law, an inaccurate understanding of the facts of the case, or a deliberate decision not to apply the law that the jury was instructed to follow to the facts of the case as the jury sincerely understands them to be.
Often everyone even knows that the jury reached its verdict because it misunderstood the law or the facts, based upon interviews with the jurors immediately following the trial, but nothing can be done about that to reverse a jury verdict if a sincere jury following the instructions could have reached the same conclusion if they'd viewed the credibility of the witnesses differently.
If the jury instructions given to the jury are legally correct, the judge does not make any serious errors in how he conducts the trial that hurt the losing party, and there is nothing extraordinary that was no one's fault but made a fair trial impossible, it doesn't matter if the jury actually followed the law or actually correctly or sincerely interpreted the facts.
In those cases, as long as it would be possible for a jury of law following people who saw the evidence presented to them and believed what the winners wanted them to believe about the evidence, the verdict will stand, even if the jury actually ignored the law.
Jury nullification in the broader (and less common) sense of the phrase used in this question, refers to cases where the jury actually ignored the law as applied to what the jury believed actually happened from a factual perspective in light of their actual knowledge and not just what was presented at trial.
This broader sense of jury nullification is distinguished from cases where the jury sincerely tried to reach a correct verdict based upon the jury instructions but screwed up in their interpretation of the jury instructions and/or their understanding of what happened factually.
While jury nullification in this broader sense isn't terribly uncommon, most jury verdicts that reach the wrong conclusion based upon misunderstandings of the law or facts are sincere screw ups and not intentional cases of disregard for the law.
Also, it isn't terribly uncommon for a jury to think that they are deliberately ignoring the law provided to them in the jury instructions when they render a verdict, because they think doing so would be unjust, when they actually misunderstood the jury instructions regarding the law and by disregarding the law as they misunderstand it to be based upon their misreading of the jury instructions, are actually following the law upon which they were properly instructed. This feels to the jurors like it is jury nullification in the broader sense, but isn't actually jury nullification.
Jury nullification in the broader sense can cause cases to be thrown out by a judge or on appeal for reasons #4 or #5, but most of the time, jury nullification will not cause a verdict to be thrown out by a judge or on appeal (even if statements from jurors after the trial make it clear that jury nullification in the broader sense actually took place), if a jury that weighed the evidence and evaluated the credibility of the witnesses differently than the actual jury did could have reached the same verdict.
Also, it isn't terribly uncommon for a jury verdict that involved jury nullification in the broader sense to be reversed for reasons #1, #2 or #3, even though none of the errors that were the basis for that reversal to actually be the reason that the jury ruled the way that it did. But, in those cases the case isn't thrown out by a judge or on appeal "because of" the jury nullification. Instead, in these situations, the case is thrown out "because of" errors which were actually harmless but could have led a reasonable jury to reach the wrong verdict.