This is what "fair use" is; it's a (legal) harmonization of the first amendment and the original Constitution. As far as the legal system is concerned, it settled this matter hundreds of years ago. I doubt you'll convince anyone to reopen the matter, and this isn't the avenue we should take anyhow. If you're going to go strict Constitutionalist, the word to be focusing on is limited. Is it a limited time when Congress retroactively extends the copyrights every time the expiration dates approach? Unfortunately, Lessig tried this last time and failed, though the ruling was such that the next time it comes up it might do better.
