Recently a San Francisco neighborhood merchants' group, the Valencia Corridor Merchants Association, announced it would seek a temporary ban on new restaurants in the up-and-coming neighborhood.

"As a merchants association, it's our job to protect the restaurants already on the corridor," said Deena Davenport, a neighborhood salon owner who also served as past president of the neighborhood association, in remarks to the San Francisco Examiner. "Our goal has always been to keep the diversity on the street."

But if the exclusionary goal of protecting existing restaurants against new competitors and the inclusionary goal of fostering diversity seem at loggerheads to you, then good on you.

Not so UC-Berkeley professor Karen Chapple, who applauds what she rightly labels "anti-competitive zoning" and calls the proposed ban "a terrific move" because it would "enact barriers to new entry to new business" and "preserve… the place's identity and keep… it as a regional destination."

Others, me included, aren't so supportive.

"A government-issued moratorium on new restaurants is a terrible idea: Consumer choice would be diminished, entrepreneurship would be stifled, and the jobs that could be created in the area by new restaurants would never materialize," says Bert Gall, a senior attorney with the Institute for Justice, in an email to me. "Moreover," says Gall, "such a moratorium would be unconstitutional: As several federal courts have recognized, mere economic protectionism of existing businesses is not a legitimate basis for government regulation."

"I honestly don't understand it," says taco restaurant owner Joe Hargrave, referring to the proposed ban in remarks he made to the Examiner. "I think it's kind of absurd."

"I'm skeptical of a moratorium," says city supervisor Scott Wiener, who oversees part of the area the ban would cover. "Even though they're asking for a moratorium of one year… moratoriums in the long run can have very negative and unintended consequences."

From his sensible comments, you might expect Supervisor Wiener would also oppose a measure introduced last month by a San Francisco supervisor to "protect [the] needs of established brick and mortar restaurants" in the face of competition from the city's food trucks. You'd be wrong.

Wiener doesn't just support the measure. He drafted and introduced it. And those words about "protecting [the] needs of established brick and mortar restaurants" are in fact… Wiener's own.

In spite of this double standard, Wiener actually appears less inclined than many of his colleagues to side with the brick-and-mortar restaurant community when conflicts arise between them and food trucks.

This infuriating brand of protectionism is hardly confined to San Francisco.

Last week a grocery and other businesses protested against a pharmacy's plan to sell beer and wine in one Washington, DC neighborhood.

And the Australian reseller Dick Smith Foods also recently issued a call to lawyers in the country with "guts and patriotism" to take action against American food seller Mars over the latter's use of an Australian flag on its tomato sauce—which is made with tomatoes grown in Australia.

Other examples of food protectionism abound—from tariffs on particular foods like honey to those impacting whole agricultural sectors.

While food tariffs are an obvious example of food protectionism (and the harm it causes), oftentimes seemingly unrelated food policies—from farm subsidies to food-safety regulations—both arise out of protectionist impulses and have a protectionist impact.

In short, food protectionism can be found in almost every industry and has a negative impact on burgeoning businesses—like new brick-and-mortar restaurants and food trucks in San Francisco—and on giant international corporations competing in far-off markets like Australia. Consumers are made worse off, too, by artificial barriers that mean food and food sellers can't meet demand.

Whether the protectionist impulses of governments and entrenched businesses are laid bare or are dressed up in calls for patriotism, planning, or public health, they share the common traits of harmfulness, ugliness, illegitimacy, and illegality. Such impacts—and the laws that lead to them—deserve no protection.