This has never happened before. Yesterday’s FDA hearing on limits for salt in food marked what may be an unprecedented shift in the agency’s regulatory role. This is not the first time that federal officials have considered controlling the availability of a widely consumed substance. Just this year, Congress granted the FDA authority to regulate tobacco. And in 2003, the agency banned ephedra. The same rationale guided these various regulations: Each substance posed an “an unreasonable risk to the public health.” But salt is different.
Why? Salt is presumed to be safe. The FDA currently categorizes sodium as “GRAS” or “generally recognized as safe.” As long as it’s GRAS, salt is protected from the dubious agenda of nutrition activists like Center for Science in the Public Interest (CSPI) nag Michael Jacobson. But Jacobson wants to get rid of the federal roadblock, saying: “Salt should be considered generally recognized as dangerous, not safe.” 
CSPI initially claimed that its desire to remove salt’s GRAS status was fueled by a desire to label foods high in salt, thereby informing consumers. At this week’s hearing, however, the group’s message changed from education to regulation. Jacobson preached that action by the FDA to restrict the use of salt is "long overdue." This switch should make Americans question whether or not CSPI’s menu labeling advocacy in general is really just about the labels.
Regardless, salt doesn’t need warning labels or federal limits. Substances previously capped or banned by the FDA were dangerous at any level. Salt on the other hand is good for public health. In fact, salt is absolutely necessary for life. The advocacy groups pushing for federal controls claim that the amount of salt consumed, rather than salt itself, is harmful. However, even at high intakes there’s no direct evidence (nothing like the proof against cigarettes) that sodium causes disease. 
Capping salt levels by government fiat would have far-reaching, detrimental implications. Let’s face it. Too much of any good thing (eggnog, TV, family, etc.) can be bad for your health. And that’s doubly true for government. Though we’re certain of salt’s merit, the science on its alleged deleterious effects is still ambiguous at best. As one Reason magazine feature explains, uncertainty should be tolerated in the laboratory, but not in the legislature:

Unlike its scientific counterpart, the political process cannot accommodate ambiguity. The vote must be yes or no, not maybe. Sanford Miller, a former Food and Drug Administration staffer now at the University of Texas Health Sciences Center, told [Science magazine correspondent Gary] Taubes that the salt controversy is the “number one perfect example of why science is a destabilizing force in public policy.”

Clarification: Yesterday (“Americans Are Gaining Laws, Not Weight”) we reported that New York City Health Commissioner Thomas Freiden told 60 Minutes that “there’s little scientific evidence that posting calories will make people eat less.” However, it was correspondent Lesley Stahl, not Freiden, who made the statement while introducing the commissioner’s willingness to implement an unproven regulation.
Researchers from the University of Vermont corroborate Stahl’s sentiment:

Despite the growing push for such legislation to be developed, and more importantly, the need for research in the area that has been identified, there has been no research demonstrating the impact that food labeling will have on consumer behavior with respect to eating out.