The US Constitution prohibits ex post facto laws. Marc
Bill Stewart wrote: > There were documents that were _going_ to become public domain soon > that will now stay copyrighted for another 20 years, > and one of the issues addressed by the Supremes in Eldred was > whether the grant of an extra 20 years of copyright monopoly to > documents that already had expiration dates assigned under the > old laws was appropriate, as distinguished from granting a > longer monopoly to new documents, but I thought it was established law > that if something once became public domain it stayed that way.
