When I photograph a public sculpture, can I sell the photograph as a fine art print?

Copyright does not just protect against exact copying of a work, it also protects against copying of the work with minor modification. The latter is known in copyright law as derivative works. Turning a book into a movie is regarded as a derivative work and doing so without the permission of the owner of the copyright on the book would be copyright infringement. Similarly, if the sculpture is copyrighted (e.g., the Statute of Liberty copyright has expired), photographing the sculpture can be regarded as creating a derivative work and selling the photograph to profit from the artistic value of the sculpture could get you an infringement suit from the copyright owner. Good luck, Todd