Neil Weinstock Netanel has self-archived "First Amendment Constraints on Copyright after Golan v. Holder" in SSRN.
Here's an excerpt:
Commentators have depicted the Supreme Court's January 2012 ruling in Golan v. Holder as a far-reaching repudiation of First Amendment limits on Congress's power to expand copyright and diminish the public domain. However, Golan imposes potentially significant First Amendment constraints on copyright protection even while granting fairly broad First Amendment immunity to Copyright Act amendments. It does so by effectively adopting Melville Nimmer's "definitional balancing" approach to resolving the tension between copyright and the First Amendment. . . As Golan applies that approach, neither Congress nor courts may "disturb" copyright law's idea/expression dichotomy or fair use privilege without running afoul of the First Amendment. Accordingly, following Golan, Copyright Act provisions and proposed legislation that would diminish one or both of those free speech safeguards remain vulnerable to First Amendment challenge.