Every once in a while, this subject comes up when I’m talking to someone, and it always amazes me how few people are familiar with the concept. The standard wording of this (when it’s written out, as it is in the Indiana Constitution) is “the jury shall have the right to determine [or judge] the law and the facts.” What does that mean, though? It means juries can find someone “not guilty.” In the common law system on which our courts are based, there wasn’t always this right. Back then, the verdict if someone didn’t commit the crime was frequently worded as “not proven.” The “not guilty” wording actually came forth from juries not wanting to convict people in cases where the letter of the law would otherwise have put them in prison (or worse) for something that the jury did not believe was sufficiently criminal. Indeed, this is the sum of the power of a trial by jury in the first place. If all that mattered was following the letter of the law, there would be no need for juries, because judges are obviously more qualified for that task. Juries exist to put an additional vital constraint on government power. By ensuring a citizen the right of a trial by jury, you promise them that they have a fighting chance of not being sent to prison (or even executed) under an unjust law.
This is why it is so important for people to understand what jury nullification is. You can argue (and be correct) that your vote in an election is very nearly meaningless. You can write letters to your “representatives” until you bankrupt yourself with postage, and never inspire any change. You can believe in the power of an individual citizen all you want, but the only place where that power really shines through is in the juries that most people in this country try like hell to avoid serving on.
Okay, that’s enough of me talking, go read about it:
Wikipedia Article on Jury Trials
Wikipedia Article on Jury Nullification
Another article about nullification
And another article on it
The Fully Informed Jury Association
The Indiana Constitution, Article 1. See Section 19. (if you live in another state, google is your friend.)