Tim Armstrong said:

“If DRM systems weren’t so restrictive and permitted the full range of fair use, what force would be left in the most common objections to the DMCA?”

Are you serious? Fair use is not the only casualty of the DMCA, and may not even be the most important casualty. The loss of the ability to reverse engineer systems for interoperability purposes is a tragedy that harms technological innovation every year the law remains on the books. The DMCA sneers at open standards, and privileges platform monopolies. Please go to http://www.techliberation.com/archives/cat_open_source_open_standards_and_peer_production.php and read Tim Lee’s excellent series on this subject. Then see if you can still argue with a straight face that the DMCA will be okay if we just insert a couple of tweaks to preserve fair use.

I’m not sure if this recent post mounts the defense that you are looking for, but I think that it is in some neighborhood of it:

http://uchicagolaw.typepad.com/faculty/2006/07/fair_use_and_ac.html

I also think that the darknet critique assumes too much homogeneity among users. By that I mean, that it assume that we don’t need DRM to police “good” users and that DRM will fail to control “bad” users. I think that the world is much more mixed than that, so that even if DRMed stuff will always make it into the clear, raising the transactions costs of getting to that content may keep a middle group of users from accessing the in-the-clear content.

It’s certainly the case that the most widespread contemporary DRM systems do a poor job of protecting fair use, as the forthcoming Berkman Center white paper on education and digital media will likely demonstrate in great detail. To the extent that the DMCA justifies or ratifies a content provider’s decision to adopt restrictive DRM, it is rightly criticized.

But here’s the point: nothing in the DMCA requires the adoption of maximally restrictive DRM. The statute is technology-agnostic; it doesn’t care what capabilities any given DRM mechanism does, or doesn’t, have. Proposals for minimally restrictive DRM (which is to say, DRM that fully permits uses that would be recognized to be fair both under the law and under the more permissive social norms surrounding individual use of copyrighted works) are abundant in the computer science literature, although they haven’t crossed over into the legal literature yet.

You write: “I don’t see how [the complaints against the DMCA] are a bim rap simply because one can imagine DRM that does less damage.” But let me flip that around: you object to the DMCA *because* existing DRM is so restrictive, don’t you? If DRM systems weren’t so restrictive and permitted the full range of fair use, what force would be left in the most common objections to the DMCA? Not much, it seems to me.

And that’s all I’m trying to get at. Complaining about the statute, rather than the technology, shifts the blame onto Congress and away from where it really belongs: on the media companies who have elected to adopt maximally restrictive DRM. I’m sure those companies are happy to have the heat deflected by the DMCA, but don’t be fooled.

Hey, but you know there are probably some people for whom the DMCA works pretty well. Somewhere out there in the long tail.