A ton of people wrote in to point out Mark Helprin's Op-Ed article in this Sunday's New York Times ("A Great Idea Lives Forever. Shouldn't Its Copyright?"); some of them suggested writing a response.
So I've written one, and sent it in to the New York Times editors. As we have no problem with right-of-first-print arrangements here :-), I'm waiting to hear back from the NYT before posting it on this site. The NYT will let us know within a week if they're going to run it. [Update: they didn't run it, so it's posted here now.]
In the meantime, though, recent Canadian law school graduate Jacob Tummon wrote in with a piece that's as good an answer to Helprin as we could ask for, although he didn't write it as a response to Helprin. It's called "The Case for the Elimination of Copyright" (http://legaltree.ca/node/559), and it's a really good, thoroughly-footnoted analysis of the cases for and against copyright — economic, moral, and legal.
Tummon writes from a Canadian legal perspective, and helpfully compares Canadian with U.S. law at several points. There are also some great quotes from skeptics in copyright jurisprudence, including Stephen Breyer, who is now a judge on the U.S. Supreme Court. All in all, highly recommended.
Ironically, at the bottom of the page is a notice saying "Copyright © 2007 Legal Tree Project Inc." I suspect that notice is just placed there automatically, and that it's questionable under Canadian law whether they actually have an exclusive copyright on the piece, but Jacob himself could probably say authoritatively.