The New York Times wrote In Supreme Court Opinions, Clicks That Lead Nowhere
"Supreme Court opinions have come down with a bad case of link rot. According to a new study, 49 percent of the hyperlinks in Supreme Court decisions no longer work."
"For most of the Supreme Court’s history, its citations have been to static, permanent sources, typically books. Those citations allowed lawyers and scholars to find, understand and assess the court’s evidence and reasoning. Since 1996, though, justices have cited materials found on the Internet 555 times, the study found. Those citations are very often ephemeral."
"The United States Court of Appeals for the Ninth Circuit, in San Francisco, could serve as a model. It maintains an electronic archive of what it calls “webcites” in the PDF format. Professor Zittrain and his colleagues are at work on a more ambitious solution, Perma.cc, a platform built and run by a consortium of law libraries. It allows writers and editors to capture and fix transient information on the Web with a new, permanent link."
Maybe they could link to archive.org instead. If they start keeping their own copies of their cited material, I wonder how long until there's a copyright lawsuit brought. The article mentions that Scalia cited a car chase in The French Connection. Stranger things have happened than Fox suing for a clip of their content posted without their permission (even in obvious fair use situations).