I have said elsewhere ("A Necessary Cost of Freedom"?) that the Supreme Court's decision in Sorrell v. IMS Health may have, for all intents and purposes, done away with the Central Hudson test which any regulation relating to commercial speech must pass. That test, for those unfamiliar with the doctrine (and really who is familiar with it outside of those litigating around it?), has 4 parts. The first two elements are almost never controversial. Prong 1 is whether the product or service is legal and whether the speech in question about that legal product or service is truthful and not misleading. (There is a wealth of complication here is this deceptively simple requirement but that is a post for another day. Suffice it to say that this is not usually where the fights are). Prong 2 asks whether a substantial government interest is involved. Again, this is not usually the question around which a fight arises.
The fights usually arise around prongs 3 and 4. Prong 3 requires that the government show that its regulation "directly advance" the goal in prong 2 and Prong 4 requires that it does so without being "more extensive than necessary" to advance that goal in prong 2.
As we look at the many public health issues - off label use marketing, junk food marketing and others - you might notice a problem. Regulatory efforts which are effective are likely to be fairly broad - say banning certain types of advertising altogether or banning in particular venues and thus will very often run afoul of prong 4. In contrast, when agencies or legislators try to very narrowly tailor a particular rule, chances seem very good that it will be harder and harder to measure effectiveness or to attribute any change to a particular measure so narrowly tailored provisions may fail prong 3. This last observation may be exacerbated by courts willingness to interpret the standards for the admissibility of expert evidence under Daubert to require unrealistic standards for causation or, at the very least, to give an advantage to those entities able to marshal a great deal of evidence to cast doubt on a particular claim. The Most Influential Supreme Court Decision You've Never Heard Of.
This may be only one of many reasons not to mourn the potential irrelevance of Central Hudson, although I caution that nominally it is still good law and the Court took pains not to overrule it. But many an effective intervention could easily get crushed between the jaws of prongs 3 and 4, particualrly in the current environment where courts seem inclined to treat claims for freedom for commercial speech so generously. That is probably bad news for the public health community and perhaps for the regulation of the marketing practices of the financial industry.