Jury nullification is a legal phenomenon in which jurors choose to acquit a defendant despite the facts and law presented to them supporting conviction. The practice is often cited as a boon for juries who wish to free sympathetic defendants and block unjust enforcement or unjust laws.

Do juries have the right to nullification, and is there any recourse for refusing to convict a defendant?

A Kind of Acquittal

Juries can acquit defendants for a variety of reasons, but it is often because they believe that the prosecution has failed to meet its burden to prove a defendant's guilt beyond a reasonable doubt. In the case of jury nullification, jurors may believe that a defendant has committed the acts alleged beyond a reasonable doubt, but may disagree with the criminal charge being applied.

For example, jurors have often refused to convict (and often acquit) defendants who are charged with possession of marijuana. According to the James A. Baker III Institute for Public Policy, in Montgomery County, Texas, less than 1 percent of possession of marijuana judgments were issued following a jury trial. Prosecutors also take notice of the charges in which juries are likely to nullify, leading to more plea bargains and fewer jury trials.

Unlike convictions, which can be appealed and overturned, jury nullification which leads to an acquittal cannot be appealed by the state, leaving the defendant free to go when the jury nullifies.

Can Jurors Be Punished for Nullification?

In general, there is very little power for the state to demand why a jury decides to acquit. The prosecution can poll the jury to hear what each individual juror decided ("guilty" or "not guilty"), but the court cannot demand any juror explain his or her reasoning.

That doesn't mean that jury nullification can't get you kicked off a jury. If a court discovers that you lied in order to sneak onto a jury with the intent to nullify, you can be removed from the jury. Jurors typically aren't criminally punished for this behavior, but a judge may find a juror in contempt of court for lying.

With seldom consequences for jurors, many view jury nullification as a low-risk way for average citizens to significantly impact criminal laws in a way that gets legislators' attention.

Source: Findlaw.com.