Patents as Tribbles

Via Slashdot, I hear that some economists at the St. Louis Fed are making an argument that a patent system will inevitably grow beyond it's original intent, such that it becomes destructive. I haven't had a chance to read this yet, but it sounds like the basic libertarian critique of the state. As a PR tool, it will be nice to have a solid written critique from an establishment source. Maybe this can get people to start thinking about this phenomenon more generally.