Yes and no. The majority opinion in Eldred v. Ashcroft clearly discusses retroactive effect: "Given the consistent placement of existing copyright holders in p

Yes and no. The majority opinion in Eldred v. Ashcroft clearly discusses retroactive effect: "Given the consistent placement of existing copyright holders in parity with future holders, the author of a work created in the last 170 years would reasonably comprehend, as the “this” offered her, a copyright not only for the time in place when protection is gained, but also for any renewal or extension legislated during that time. Congress could rationally seek to “promote … Progress” by including in every copyright statute an express guarantee that authors would receive the benefit of any later legislative extension of the copyright term. Nothing in the Copyright Clause bars Congress from creating the same incentive by adopting the same position as a matter of unbroken practice."[1] Stated rational by above post isn't quite the same as the point made in Eldred, but it's based on the same idea -- i.e. parity between terms for newly created works and previously created works. [1] http://www.law.cornell.edu/supct/html/01-618.ZO.html http://www.law.cornell.edu/supct/html/01-618.ZO.html