I HAVE voted in every single election in which I was allowed to vote, but I have only been summoned for jury duty twice. Once I was seated for a civil-liability case involving a six-year-old auto accident; an hour before the trial was to begin the parties settled. The second case was an especially nasty violent crime; as it happened, the prosecutor asked me whether anyone in my family had ever been the victim of or witnessed such a crime. One had; I went home. All of this is a complaint, but not in the way you might think. I love jury duty. I love the institution; I love getting the summons; I love being in a courtroom; and I suspect that if I ever actually served as a juror during a trial I would love that too. Stirring strings and waving flags in politicians' campaign spots annoy me. So does the ritual of singing the Star Spangled Banner before every single baseball game. But put me in a voting booth or ask me to serve on a jury and I get as misty-eyed and patriotic as my immigrant great-grandparents.

Juries do not only decide guilt or innocence; they can also serve as checks on unjust laws. Judges will not tell you about your right to nullify—to vote not guilty regardless of whether the prosecution has proven its case if you believe the law at issue is unjust. They may tell you that you may only judge the facts of the case put to you and not the law. They may strike you from a jury if you do not agree under oath to do so, but the right to nullify exists. There is reason to be concerned about this power: nobody wants courtroom anarchy. But there is also reason to wield it, especially today: if you believe that nonviolent drug offenders should not go to prison, vote not guilty. The creators of the television show "The Wire" vowed to do that a few years back ("we will...no longer tinker with the machinery of the drug war," wrote Ed Burns, Dennis Lehane, George Pelecanos, Richard Price and David Simon). And the illustrator of the children's book that has every author banging his head against his desk and every parent cackling just wrote a sweet if somewhat simple guide to nullification. The Fully Informed Jury Association has more. Happy Friday evening.