California, in the person of state Sen. Deborah Ortiz, has declared war. Not on drugs, gangs or guns. Not on teen pregnancy, school dropout rates or violent Hollywood movies. This war is being waged against 12-ounce cans of soda pop. Ortiz, a Sacramento Democrat, won’t declare victory until all things fizzy are banished from our schoolchildren’s line of sight.

Obesity-warriors like Ortiz – the same legislator who wants food menus with endless nutrition warnings (e.g., “ice cream contains fat and sugar”) – believe they have a mandate to teach us all the basics about health and nutrition. Parents, under the wishful impression that keeping their kids physically fit is their job (not the government’s), stand corrected.

But it’s even more aggravating that Ortiz relies on the kind of evidence that wouldn’t pass a high school science class. The Ortiz bill, which has passed the Senate and is before the Assembly, would ban all soft drinks from school because of two Harvard studies whose conclusions are the stuff of urban legend.

One study, by a researcher named Grace Wyshak, tried to connect soda consumption in young girls with bone fractures. But Wyshak didn’t measure bone density. She never asked how much soda the girls in her study drank. She never found out if any of them played sports, fell down stairs, got in fights or had abusive parents.

Wyshak admitted in her own conclusion that “causality cannot be inferred from the data.” She never came close to proving that soda pop had anything to do with broken bones. But Sen. Ortiz uses this hollow “study” anyway, claiming in the text of her bill: “A study of ninth- and 10th-grade girls found that those who drank colas were five times more likely to develop bone fractures.”

The other piece of scientific debris on which Ortiz leans heavily is a report on sugar consumption by Harvard’s David Ludwig, who asked hundreds of Boston middle-schoolers about their TV-viewing habits and soft-drink consumption over the prior month.

Newspapers had a field day when this study was first released, claiming in 48-point headlines that every can of sugared soda made children 60 percent more likely to end up supersized themselves. But did Ludwig really prove this? Well, no. As 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 truth: Ludwig never established a scientific link between sugar intake and chubby seventh-graders. As the Centers for Disease Control and Prevention later wrote: “There are no data from the [Ludwig] study that allow us to make an estimate of what proportion of obesity might be accounted for by changes in soft-drink consumption.”

Of course, the mass media chose the convenient over the complicated. And that’s OK; most Americans are accustomed to taking sound-bite television pop-science with the appropriate grain of salt. We should, however, expect a more thorough and conscientious job from elected legislators.

A sober, responsible look at nutritional science tells us that childhood obesity is far too complex a problem to be fixed by turning any particular food or beverage into forbidden fruit. Short of replacing Web-surfing and channel-surfing with actual surfing or any consistent exercise program, there’s no quick fix for overweight kids.

Health advocates from the American Dietetic Association tell us that there is no such thing as a “good” food or a “bad” food. It’s all in how you use it.

But this message never seems to be heard through the smokescreen of know-it-alls spouting half-baked summaries of Harvard studies, as though one of the world’s most complex public-health puzzles can be solved by blindly trusting a few experiments that everyone agrees have proved nothing.

There’s more bad science out there than good. California lawmakers ought to be demonstrating that they can tell the difference instead of teaching our kids an irrational fear of pop. Scientific literacy, too, is a worthwhile goal for our schools.