Advocating for a controversial legal tactic known as jury nullification can get U.S. citizens prosecuted for jury tampering, according to one Manhattan prosecutor who's pursuing that very charge against a 79-year-old former chemistry professor.

Indicted last year, all Julian P. Heicklen says he was doing is handing out pamphlets from the Fully Informed Jury Association near a courthouse. He wasn't targeting any specific jury or juror, and his activism has taken him to dozens of courthouses around the country, according to The New York Times.

Manhattan prosecutor Rebecca Mermelstein argued in a recent court filing examined by the paper that because he hoped to "target prospective jurors," he was tampering with the legal process.

"I'm not telling you to find anybody not guilty," he allegedly told an undercover officer. "But if there is a law you think is wrong then you should do that."

Essentially, he's right: Jury nullification is the right of citizens to nullify the application of laws the feel are unjust. During alcohol prohibition, nearly 60 percent of trials were nullified by jurors. Nullification was often used in cases involving the Alien and Sedition and Fugitive Slave Acts, but it was also common in the South, where it was used to stymie civil rights trials.

But far from being a rarely used, forgotten tactic, just last year jurors nullified charges against a Montana man accused of possessing 1/16 of an ounce of marijuana, regardless of any evidence the state presented against him. In an even more recent case, George Washington University law professor John Banzhaf suspected that jury nullification was used to spare former Illinois Gov. Rod Blagojevich during his first public corruption trial, although he was later convicted by a separate jury.

The use of nullification in drug trials is what brought Heicklen to his activism in the first place, he told the Times. In the 90s he smoked marijuana out in public, just so he could get arrested in protest of its prohibition, their report noted. That's when his true advocacy of jury nullification began, arguing for its use as a means of negating minor drug and gambling charges.

That, too, is not unheard of today: in July 2010, a former Texas police officer who turned against the drug war and became an activist filmmaker was arrested on charges of making a false report to a peace officer, which he earned by attempting to film police committing crimes. He turned himself in to state troopers after a press conference at the Texas capitol, the words "jury nullification" written across his forehead.

Unsurprisingly, Heicklen has asked the judge for a jury trial.

The prosecutor, also unsurprisingly, is opposed. Mermelstein wrote that Heicklen would just "urge a jury to [nullify] in a case against him," which, in her view, is "not protected by the First Amendment."

With prior reporting by David Edwards.

Photo: Flickr user Kaja.A.