Straight after "mad monk" Peter Murnane and his merry men popped the Waihopai spy satellite balloon two years ago, I suggested the spy bosses were on to a loser dragging the protesters through the courts.

If they wanted the tittering to end, persuading the saintly trio to stick the thing together with a tube of superglue would have been a wiser solution.

How right I was. A jury of 12 upright Wellingtonians have now found the men not guilty of charges of burglary and wilful damage to property, even though they admitted cutting through fences surrounding the satellite dish, then slashing its inflatable cover with sickles.

The right-wing commentariat has been suffering from apoplexy ever since. Commie plots, lunatic jurors, we've had the lot. Paul Holmes knew they were guilty just by looking at pictures of them.

He was particularly affronted that their wardrobe wasn't of the same haute couture tailoring that he'd grown accustomed to as the highest paid star at state television.

With his pink hanky to his nose, he gasped that they "dressed in the clothing of the anti-American far left" and "do not seem to take any pride in their appearance".

To Holmes it was a "dopey decision" by a "queer jury" of "likeminded misguided conspiracy theorists". Given his well-publicised family problems, I'd have thought the possibility of a "queer jury" thinking outside the narrow legal square might have had its attractions.

Talkback host and ex-MP John Tamihere took an equally crazed line, but on the racist grounds that if they'd been "darkies" like Tame Iti they'd have been charged with terrorism and every other charge possible, found guilty and thrown in jail.

A more optimistic viewpoint would have been that the Waihopai decision proves beyond doubt that New Zealand juries are not just tools of the state, and when needed, can have a mind of their own.

The defendants had used the rare, in New Zealand, defence of the greater good; in this case, that pricking the balloon would force the spy satellite monitoring station to close down, at least for a while, and thus end or temporarily stop the human suffering overseas that the spy activities caused.

Far from being a sign that the jury system is flawed, last week's decision revealed it as the human safety valve that more authoritarian legal systems sadly lack.

Whether the jury actually bought this obscure legal argument, we'll never know. In this country, what goes on in the jury room stays there.

What the jurors appear to have done was exercise what the Americans call the power of jury nullification, which dates back to the early days of English law.

Lawyer and author John Mortimer's famous television character, Horace Rumpole, summed it up thus: "If Miss Tuttle's broken the law, the jury are entitled to acquit her! It's their ancient and inalienable privilege, I shall tell them. It's the light that shows the lamp of freedom burns."

Up to 1670, English juries had defied the instructions of judges at their peril. The change came in 1670 when William Penn was arrested for illegally preaching a Quaker sermon.

Despite the judge's instructions to convict, the jury acquitted him and were promptly imprisoned and fined for their impudence. On appeal they were released and the precedent set that jurors could not be punished for their decisions.

Chief Justice Vaughan said the jury "resolve both law and fact, and not the fact by itself".

A judge, he said, could not interfere because "a man cannot see by another's eye, nor hear by another's ear; no more can a man conclude ... by another's understanding or reasoning".

Around the early years of the 19th century, English juries defied prosecutors by returning not-guilty verdicts on petty criminals knowing a guilty verdict meant the noose.

Last year, Otago law dean Mark Henaghan extolled the independence of juries as one of the system's great strengths. He told the University of Otago Magazine:

"Juries prevent the law from being a mechanical process that could be dispensed by a computer programme or legal technician. It's what gives the law its soul."

He said juries should be "directed by law, but not answerable to it. That's its brilliance. It's the prerogative of juries to return verdicts that reflect their conscience, if not the law, and it's right that [they] should not have to answer for that".

He recalled the case of a despairing father who returned from hospital having been told his baby daughter was one step from brain-dead and then suffocated her.

"Yes, it was the unlawful taking of life, but the jury clearly did not have the heart to convict him. That tells us much more about the society we live in than the law ever could."

The same goes for the excellent verdict of the "queer" jury in Wellington.

My guess is, the "claim of right" defence, however obscure, provided them with the framework they needed to do what they wanted to do.

Waihopai is part of the United States war machine. The jury knew that, just as all New Zealanders should.

Defendant Adrian Leason summed it up on Campbell Live. "We broke a law to protect plastic to uphold a law to protect human life. The jury heard that and said yes, protecting life matters more than protecting plastic."

Prime Minister John Key is talking of reviewing the "claim of right" defence.

He's on to a loser, just as the spy bosses were on to a loser in prosecuting these three. Even without this defence, the jury could have said not guilty.

As Horace Rumpole said: "It's their ancient and inalienable privilege."