The principle of jury nullification is a valid check on what
could otherwise be the heartless power of the law. In jury nullification, a jury
ignores the letter of the law and obeys its spirit. For example, a jury might
agree to free a man who helped a wife to die, and freed her from the torture of
an end-stage cancer. Another jury might decide that a battered woman who turned
on her tormentor does not deserve thirty years in jail. Jury nullification
tempers justice with empathy.
A jury has the right to nullify a defendant's possible conviction if it feels the law doesn't apply to one particular person. Hung juries, where not everyone agrees to one verdict, are becoming more common. Although rarely used (in just four percent of American cases that go to trial), jury nullification is one way to get around the law. As part of the American justice system, jury nullification is already part of the three-faceted "checks and balances" written into the Constitution.
While the concept of jury nullification sounds attractive, I don't think it's something the government outside of the District Attorney is really paying attention to. Jury nullification do not set legal precedent, the next defendant facing similar circumstances could just as easily be found guilty. This makes it worthless as a form of government check.
The problem with jury nullification is that there's no way to make it an effective political movement or statement. Jury selection happens at random, and it's usually people who are, to be frank, not clever enough to come up with a good enough excuse to get out of doing it. These are not people who are going to be part of a movement, therefore rendering nullification useless.
The principle of jury nullification should not be used as government check. Jury nullification occurs in a trial when a jury acquits a defendant they believe to be guilty of the charges against them. This sometimes happens when the jury disagrees with the law with which an individual was charged with. This is just a quick way to get to a ruling and should not be used.