The law would extend copyrights on works retroactively, so a lifetime of photos that are already in the public domain would be re-captured by copyright. That would bring about a huge amount of legal uncertainty over works that have already been shared, remixed, sold, and modified in innumerable ways. If this bill passes, many tens of thousands of photographs that have been uploaded into cultural archives, including Wikipedia, may have to be erased from the Internet or else they could face civil, or even criminal prosecution failing to do so.