To understand why the statewide teachers union is right to ask a judge to strike down new rules requiring parental notification of teacher arrests, look no further than today’s headlines and the examples of Dominique Strauss-Kahn and Casey Anthony.

These cases reveal something important about our society and the knee-jerk conclusions we instinctively draw about people accused of a crime.

Let’s back up. In 2009, two licensed educators with the Poudre School District were arrested. Subsequently, Fort Collins resident and State Board of Education chairman Bob Schaffer pushed for new rules requiring the school district to notify parents within 24 hours if any school employee who has contact with students is arrested or charged with any of a specific set of crimes.

Schaffer argued that, because the information is already public — county sheriffs must release to the public the names of people arrested and the charges — there’s no harm in making that information more easily available to parents.

But such proactive dissemination of arrest information sends an implied message that the arrest proves wrongdoing. It’s prejudging. That’s why the teachers union is right to object.

The American system of criminal justice says that citizens are innocent until proven guilty, but human nature can easily challenge that philosophy.

I was stunned at the speed with which the public condemned Dominique Strauss-Kahn, former managing director of the International Monetary Fund and one-time contender to be the next President of France. When he was arrested for sexually assaulting a hotel maid, his fortunes reversed overnight. J’accuse! The public had made its decision. He lost his job and fell into disgrace.

Then, the alleged victim’s credibility was called into question and the prosecutor’s case began to unravel. Again instantly, the public pendulum reversed direction. He was set up! And now, late-breaking news, a French novelist has accused Strauss-Kahn of attempted rape in 2003, and the public cries, “Right the first time!”

I do not defend this man but cite his case only as an example of how arbitrary and capricious the public is in determining innocence versus guilt.

The public is unqualified to judge. I also do not defend Casey Anthony, indicted on charges of murdering her daughter and then found not guilty because of a lack of definitive evidence. But I’m stunned at the ferocity of people so convinced the jury erred that they would suspend the double jeopardy clause, that part of our Constitution that prohibits prosecution for the same offense twice.

We love a clean story, good guys and bad guys, without the unpleasantness of complexity. The media helps, choosing photos of the accused that make them appear shifty. We parade the accused in a “perp walk,” a curiously American ritual of humiliation, and feel the self-righteousness of pelting prisoners in wooden stocks with rotten fruit.

Human nature has a hair trigger in presuming guilt; we shouldn’t institutionalize the temptation to do so. Strauss-Kahn and Anthony may have committed the crimes, but we must respect due process and “innocent until proven guilty.” We must avoid prejudging the accused, which is what these new notification rules encourage.

Sending out alerts to parents when a teacher is arrested implies “guilty unless proven innocent later.” It’s mob mentality. We’re better than that. Besides, as Schaffer said himself, it’s already public information. That’s public enough.