‘Be very slow to believe that you are wiser than all others; it is a fatal but common error. Where one has been saved by a true estimation of another’s weakness, thousands have been destroyed by a false appreciation of their own strength.’ –COLTON.

At least 311 innocent people were condemned by “commonsense.” There are probably a lot more languishing in our dungeons, but at least that many convicted inmates have been exonerated through DNA. I bet in each one of those trials the prosecutor told the jury to use their “god-given commonsense” to fill in any gaps in the evidence and convict the accused.

I pondered this on Sunday while reading an article in the New York Times headlined: “Insider Jury-Room Demonstration Persuaded Holdouts in Ex-Trader’s Trial.” From the title I expected the jury did some intricate demonstration that proved the case for the prosecution, but this was hardly true. Here is what happened:

“Two jurors still held doubts about whether Michael S. Steinberg, the highest-ranking SAC Capital Advisors employee to be accused of insider trading, explicitly knew that his analyst had given him illegal tips. Dozens of emails, phone records and trading charts had failed to clear up their lingering hesitations about Jon Horvath, the analyst and the government’s star witness.

Then, on Wednesday afternoon — after a lunch of vegetable-and-turkey wraps and burgers — the two holdouts had a breakthrough. One juror asked Demethress Gordon, the jury forewoman and one of the holdouts, to walk through a doorway. She complied, and the fellow juror said, ‘I told you to go through the door, but I didn’t tell you explicitly how to go through the door,’ Ms. Gordon recalled in an interview. ‘It’s like the elephant in the room — it’s obvious you know what to do,’ she added.”

The problem for the prosecution was that Horvath, their sole cooperator, admitted on cross-examination that he had “never told Mike Steinberg explicitly that it was illegal information.” So the jury leaped that gap for the prosecutors because it was as “obvious” as walking through a doorway. And this solved the thorny problem of proving intent and knowledge.

Sadly the same dynamic corrupted the now infamous Michael Morton trial. The CNN special documentary on his exoneration interviewed the jurors to find out why he was convicted on such filmsy evidence. The jurors said “well, he was the only suspect. He was the husband and he didn’t have any evidence of his innocence.” And even more telling, one juror, fumbling for an excuse, said, “I guess you can’t trust your gut to find someone guilty.”

In the George Zimmerman trial, prosecutor John Guy used “Commonsense” as his summation theme: “This isn’t a complicated case, it’s a common sense case.” “It’s not a case about self-defense, it’s a case about self-denial.” And he cleverly diminished the standard of “reasonable doubt” by leavening it with a dose of “common sense”: “Reasonable doubt must be two things, it needs to be reasonable, common sense reasonable, and it needs to go to an element of the crime.”

Mark O’Mara didn’t ignore this and noted that “common sense will work against my client.”The jury should not “connect the dots” or “extrapolate” anything that the prosecution itself did not put into evidence. There was no evidence presented, he said, that Zimmerman ran after Trayvon. “Don’t let the state make you make assumptions.”

Prosecutors use “commonsense” as a type of jury nullification – an invitation to ignore the jury instructions – but judges find it acceptable because it works in favor of the prosecution. How dangerous is this? Take the book “In Commonsense Justice: Juror’s Notions of the Law”, where Norman Finkel suggests jurors reject “black letter” law for “commonsense justice” or “community sentiment,” and “what ordinary people think the law ought to be” and “should the law follow the path laid by community sentiment, or should the community follow the path the law has laid?” His conclusion is that the law is out of step with common sense. Finkel argues that the jury’s role is to provide a corrective for legislative excesses, and that commonsense justice is “more deliberative and conscious, and quite sensitive to foundational issues of justice.” Dangerous? You bet.

Jurors readily accept this argument because they believe their commonsense is pretty good and it seems right based on their life experiences. This is dangerous yet hard to rebut because it is such an appealing idea. “Let’s ignore all this legal mumbo jumbo and figure this out ourselves.” It allows all their biases and prejudices to come into play. “I know all about this. I saw it on Fox News.”

Unlike our clients, we can’t remain silent. Perhaps an argument along these lines: “We deal with judicially proven facts. Not speculation. Not gut instinct. Not some vague personal feelings. The prosecutor’s argument is their code for ignoring the lack of facts and asking you to fill in what they didn’t or couldn’t prove. They have the burden of proving the accusations beyond a reasonable doubt – not you. And to meet that burden they need hard concrete facts. This is not the time to jump to conclusions, or make assumptions.”

Scott Greenfield from the blog Simple Justice has a telling rebuttal: “I … implore them to use “UNcommon sense.” Don’t jump to conclusions. Don’t assume. Don’t let the prosecution off the hook for failing to prove its case. Expect more and demand it. So when the prosecutor utters the words “common sense,” a bell should go off in the jurors’ heads that what she’s really saying is: “This is where my evidence fails, and I’m asking you as good boys and girls to give me a free pass. I’m the government. Trust me.”

Trust me, if you remain silent on this it will be dangerous to your clients’ health and freedom.