In a recent presentation, the top executive of Campbell Soup Co. made the case for mandatory labeling of foods made with bioengineered ingredients. Speaking before investment analysts, Denise Morrison, president and chief executive officer, said the food industry would be better off with a single mandatory standard than a patchwork of state laws that would be “costly, impractical and confusing.”

Tracing Campbell’s shift away from its more mainstream position in favor of voluntary labeling to preempt state laws, Ms. Morrison said the issue and her company have “evolved.” “Everyone knows that the majority of Americans want G.M.O.s labeled,” she explained. In fact, the reality is not so simple. For most Americans, bioengineered ingredients do not rank high among food safety or health concerns. Similarly uncertain is a second assertion by Ms. Morrison that “everyone knows” the G.M.O. issue is one of the most pressing facing the food industry.

It may be true that a mandatory labeling law would be better than a patchwork of state laws. Better still is a renewed congressional effort, led by Senator Pat Roberts of Kansas to make labeling voluntary. The food industry rightly grouses over the costly and mounting burden of unnecessary regulations. There is no reason to advocate labeling requirements that offer consumers no demonstrable benefits whatsoever.