When George Washington University law professor John Banzhaf announced to the national media that he was leading the charge to sue restaurants on behalf of obese customers, most Americans were appalled. We all rolled our eyes and thought, “Who’s next?”

But now that Banzhaf is threatening, from 3,000 miles away, to haul individual Seattle School Board members into court over the district’s recently renewed soft-drink-vending contracts, it’s probably more accurate to wonder: “Who’s left?”

Banzhaf has jumped on a popular anti-soda bandwagon that’s fueled by junk science and media frenzy.

No one claims that soda is a health food — not even the four School Board members who voted to raise $345,000 next year by stocking school vending machines with soft drinks. But before trial lawyers run off and sue public servants who receive less than $5,000 a year for their work, they ought to have some real science backing up the wild claim that soda consumption causes childhood obesity.

As it happens, the kind of evidence that Banzhaf and his lawsuit-happy brethren use to demonize fizzy drinks wouldn’t pass muster in a high-school science class.

One of two popular studies frequently cited by anti-soda activists was published by a Harvard University researcher named Grace Wyshak, who tried to base bone fractures in young girls on soda consumption. But Wyshak’s research left out a few important measurements: She never checked the children’s bone density, and made no analysis of how much soda they drank.

Wyshak admitted in her study’s conclusions that “causality cannot be inferred from the data.” Translation: I didn’t prove anything.

The other pop-science myth on which public health zealots and trial lawyers are hanging their anti-soda hat is the notion that the sugar in soda causes obesity. In a media-savvy but flawed study, Harvard researcher David Ludwig claimed that every can of soda consumed by children made them 60 percent more likely to end up super-sized.

There was only one problem: Like Wyshak’s report, Ludwig’s own research didn’t support his suspicions about soda.

In Ludwig’s study, hundreds of Boston middle-schoolers were asked how much time they spent in front of the TV and how many soft drinks they drank during the prior month. Parents, if your 12-year-old boy can accurately tell a stranger in a lab coat how much of anything he consumed in the last 30 days, there’s a part for him in a “Rain Man” sequel.

When the dust settled, Ludwig himself admitted: “There is no clear evidence that consumption of sugar per se affects food intake in a unique manner or causes obesity.” The Centers for Disease Control was even more forceful. “There are no data from the (Ludwig) study,” wrote the CDC, “that allow us to make an estimate of what proportion of obesity might be accounted for by changes in soft-drink consumption.”

Unfortunately, common sense and moderation make for boring news stories. We never see large headlines screaming, “Soda consumed in moderation is OK.” Instead, the mass media, trial lawyers, and public-health control freaks build their cases (and their lawsuits) on sensationalistic quicksand.

So if soda isn’t to blame, why are kids so much heavier today? While obesity is a complex lifestyle problem, the most credible research available shows that kids are more sedentary today than ever before. They used to shoot baskets after school; today they shoot characters in video games.

Getting kids moving again should be our No. 1 priority. Dr. Lisa Sutherland, co-director of the University of North Carolina’s clinical nutrition research center, analyzed CDC data to determine why obesity among teenagers has risen. She reports that from 1980 to 2000, teens’ physical activity decreased 13 percent, while their caloric intake rose just 1 percent.

Today, 49 of 50 U.S. states no longer require daily physical education classes in school. And the American Cancer Society reports that in New York City, four out of five high schools fail to meet citywide phys ed standards.

Rather than focusing on the benefits of phys ed classes and exercise, attorneys like Banzhaf choose to focus their efforts on where the money is — by demonizing soda sales and school boards.

From his Washington, D.C., office, Banzhaf has been running an aggressive e-mail campaign in an attempt to intimidate school board members into seeing things his way, threatening that the Seattle School Board as a whole would suffer serious consequences, including a lower credit rating, simply by being named as a defendant.

Thankfully, School Board members chose to stand firm in the face of Banzhaf’s threat, at least for now. When the next round of this fight begins — and it will — they would do well to focus on the lessons they would be teaching our kids by creating a forbidden fruit out of a harmless beverage rather than teaching the benefits of common sense and moderation in our diets. Besides an irrational fear of carbonated beverages based on innuendo and fizzy research, there’s also the tragic lesson that scientific literacy is not worth what it used to be.

— David Martosko is director of research at the Center for Consumer Freedom, www.consumerfreedom.com, a nonprofit coalition supported by restaurant operators, food companies, and concerned individuals.