Facially Viewpoint-Based Statutes Are Unconstitutional Even if They Aren't "Substantially" Overbroad

So the majority held in today's decision about the exclusion of "immoral or scandalous" marks from trademark registration (the FUCT case).

When a statute is challenged as violating the First Amendment on its face (as opposed to just as it was applied to this particular challenger), the Court often asks whether the law is "substantially" overbroad:

In the First Amendment context, … a law may be invalidated as overbroad if "a substantial number of its applications are unconstitutional, judged in relation to the statute's plainly legitimate sweep."

If the law is unconstitutional only as to a relatively modest set of applications, then it's not substantially overbroad, and won't be struck down on its face (though people can still challenge it in those particular applications).

But in today's Iancu v. Brunetti (the case involving the FUCT trademark, and the Lanham Act's provision that "immoral or scandalous" trademarks can't be registered), the Court held that this doesn't apply to viewpoint-based restrictions:

[T]he Government … [argues that the statute may constitutionally be applied] to lewd, sexually explicit, or profane marks … [and] invokes our First Amendment overbreadth doctrine, [asking] us to uphold the statute against facial attack because its unconstitutional applications are not "substantial" relative to "the statute's plainly legitimate sweep."

But … this Court has never applied that kind of analysis to a viewpoint-discriminatory law. In Tam, for example, we did not pause to consider whether the disparagement clause might admit some permissible applications (say, to certain libelous speech) before striking it down. The Court's finding of viewpoint bias ended the matter. And similarly, it seems unlikely we would compare permissible and impermissible applications if Congress outright banned "offensive" (or to use some other examples, "divisive" or "subversive") speech. Once we have found that a law "aim[s] at the suppression of" views, why would it matter that Congress could have captured some of the same speech through a viewpoint-neutral statute?

An important holding that could apply to many First Amendment cases that are far removed from Brunetti.