[149] Adler, Inverting the First Amendment, supra note 6.  

[150] See generally

Miller v. California, 413 U.S. 15, 24 (1973) (delineating the current three-pronged obscenity standard);

Memoirs v. Massachusetts, 383 U.S. 413 (1966) (stressing that under the Roth obscenity test, a work must be utterly without social value before it can be considered obscene);

Roth v. United States, 354 U.S. 476 (1957) (holding that "obscenity" is not protected speech).

 Under this approach, the Court develops a definition of speech that can be banned, which then serves as a limit on legislative enactments. It recurs throughout First Amendment law.

For example, it is the approach taken by the Court in the subversive advocacy cases, which developed over the years into the current Brandenburg "incitement to imminent lawless action" standard. Brandenburg v. Ohio, 395 U.S. 444, 449 (1969).

Of course, one explanation for the Court's passive pose in Ferber is that the Court there was upholding a statute, whereas in Brandenburg, it was invalidating a statute. Arguably, striking down a statute requires explanation of constitutional limits in a way that upholding a statute might not. But this was not the case with Roth, the Court's first obscenity case. Even though the Court was upholding a statute and Roth's conviction under it, Justice Brennan's opinion nonetheless announced a standard constitutional definition of obscenity, one that the Court struggled to revise in Memoirs and finally in Miller.

[151] United States v. X-Citement Video, Inc., 513 U.S. 64, 78 (1994) (holding that it was necessary to prove that the defendant knew that the children in the materials were minors);
New York v. Ferber, 458 U.S. 747, 765 (1982) (holding that in the context of child pornography "criminal responsibility may not be imposed without some element of scienter").
This requirement is borrowed directly from obscenity law. See Smith v. California, 361 U.S. 147, 154-55 (1959) (establishing obscenity law scienter requirements).  

[152] Again, this was not an innovation unique to child pornography law, but rather a standard borrowed from obscenity law. See Miller, 413 U.S. at 23-24.  

[153] In Massachusetts v. Oakes, 491 U.S. 576 (1989), a case which turned on mootness, two Justices voted for the plurality's result - to remand the case - but did not join the plurality's reasoning.
Instead, Justice Scalia, joined by Justice Blackmun, argued that the Court should have reached the merits of the case. Id. at 588 (Scalia and Blackmun, J.J., concurring).
They then opined that the Massachusetts statute at issue, which criminalized a vast amount of child nudity and which reached further than any child pornography statute upheld by the Court, was not overbroad. Id.