U.S. Code Title 17 is the definitive legal resource for the U.S. Laws regardining copyright. This resource has relevant information on what constitutes copyright infringement and what actions are needed to remedy said infringements.
I will use the above resource as a primary source. This source will help me to define exactly what copyright infringement is according to the law. The above material will help me to define what actions a librarian could take when addressing sensitive copyrighted materials. By knowing the extent of the law I could then determine what are suitable actions to take when coming in contact with something which is questionable -- and in turn what is definitively illegal -- in order to argue for what actions a librarian could take to "push the envelope" on copyright law.