From Justice Kagan's concurrence, joined by Justice Sotomayor, in today's Chiles v. Salazar:
[A.] The Court today decides that the Colorado law challenged here, as applied to talk therapy, conflicts with core First Amendment principles because it regulates speech based on viewpoint. I agree. I write only to note that if Colorado had instead enacted a content-based but viewpoint-neutral law, it would raise a different and more difficult question.
As the Court states, governments must "nearly always" abstain from adopting viewpoint-based restrictions. Those laws represent a particularly "egregious form" of content-based regulation, implicating First Amendment concerns to the highest possible degree. A law drawing a line based on the "ideology" of the speaker—disadvantaging one view and advantaging another—skews the marketplace of ideas our society depends on to discover truth. And such a law suggests an impermissible motive—that the government is regulating speech because of its own "hostility" toward the targeted messages. If the First Amendment prohibits anything, it is the "official suppression of ideas." …
Consider a hypothetical law that is the mirror image of Colorado's. Instead of barring talk therapy designed to change a minor's sexual orientation or gender identity, this law bars therapy affirming those things. As Ms. Chiles readily acknowledges, the First Amendment would apply in the identical way. Once again, because the State has suppressed one side of a debate, while aiding the other, the constitutional issue is straightforward.
[B.] It would, however, be less so if the law under review was content based but viewpoint neutral. Such content-based laws, as the Court explains, trigger strict scrutiny "[a]s a general rule." But our precedents respecting those laws recognize complexity and nuance. We apply our most demanding standard when there is any "realistic possibility that official suppression of ideas is afoot"—when, that is, a (merely) content-based law may reasonably be thought to pose the dangers that viewpoint-based laws always do. But when that is not the case—when a law, though based on content, raises no real concern that the government is censoring disfavored ideas—then we have not infrequently "relax[ed] our guard." …
Medical care typically involves speech, so the regulation of medical care (which is, of course, pervasive) may involve speech restrictions. And those restrictions will generally refer to the speech's content. But laws of that kind may not pose the risk of censorship—of "official suppression of ideas"—that appropriately triggers our most rigorous review. And that means the "difference between viewpoint-based and viewpoint-neutral content discrimination" in the health-care context could prove "decisive." Fuller consideration of that question, though, can wait for another day. We need not here decide how to assess viewpoint-neutral laws regulating health providers' expression because, as the Court holds, Colorado's is not one.
Here's more from her opinion dealing with a similar question in Reed v. Town of Gilbert (2015), which she cites in her opinion in Chiles:
