In US v. Stevens, No. 08-769, the Supreme Court affirmed the Third Circuit's reversal of defendant's conviction under 18 U.S.C. section 48 for selling videos depicting dogfighting, on the ground that section 48 was substantially overbroad, and therefore invalid under the First Amendment, because section 48 explicitly regulated expression based on content and was thus presumptively invalid.
As the Court wrote: "Congress enacted 18 U. S. C. Section 48 to criminalize the commercial creation, sale, or possession of certain depictions of animal cruelty. The statute does not address underlying acts harmful to animals, but only portrayals of such conduct. The question presented is whether the prohibition in the statute is consistent with the freedom of speech guaranteed by the First Amendment."