Robert Anton Wilson's 1994 anthology, Chaos and Beyond, has a a stirring essay, "Jury Nullification: Freedom's Last Chance." Wilson says the doctrine that a jury may judge the law instead of the facts has "major potential" to help uphold the Bill of Rights. He cites the John Peter Zenger case (1734), which every well-informed journalist knows was an important First Amendment case.
This message evidently does not resonate with the federal authorities. The New York Times reports on the case of retired Penn State chemistry professor named Julian P. Heicklen who is an activist for jury nullification and hands out pamphlets on the subject outside a courthouse. Mr. Heicklen has been indicted for "jury tampering."
Here is an interesting paragraph from the Times report: "He said his activism on nullification dated back to just after he retired in the early 1990s, when he openly smoked marijuana in State College, Pa., to get arrested as a protest against marijuana laws. For this, he was arrested about five times. Mr. Heicken has said that otherwise he does not smoke marijuana."