Copyright assignment law seems to contain a massive loophole that has not been addressed by either Congress or the Courts. As a result, it is possible that an issue of copyright law would be solved by looking at state law, a curious anomaly for a federal cause of action.
The issue in question involves the assignment of copyrights. As it stands, when a copyright is assigned from one owner to another, the transfer must explicitly, by statute, include accrued causes of copyright infringement; if it does not, then the new owner does not have standing to prosecute the causes of infringement that occurred when they were not the owner.
The law does not, however, address what happens if the assignment is backdated. In this case, in theory, the assignment should be valid "as of" the date it was backdated. This, however, circumvents the intention of the law, which was designed to prevent a situation where 2 parties could potentially sue for the same copyright violation.
Moreover, copyright law doesn't take into account this basic contract principle. As a result, it is possible that courts might look to state law to decide the issue, thereby effectively creating different law applying to copyright in different states, a curious anomaly for a federal statute.