The Supreme Court this week upheld the power of Congress to restore copyright protections to public domain work against challenges based on the Copyright Clause of the U.S. Constitution. 

In a nutshell, the ruling opens the door for Congress to restore, or remove, copyright protections from any work so long as it has a rational basis to believe that doing so will “promote the Progress of Science and useful Arts.” 

For a more in depth discussion of the case, see coverage by The New York Times (available here) and the ABA Journal (available here).