“The Italian government has successfully brokered deals with American museums and private collectors for the return of what it says are looted antiquities. But it is finding the Ny Carlsberg Glyptotek, an art museum in Copenhagen, harder to crack. … At the core of the dispute are Etruscan and Greco-Roman objects that the Glyptotek bought from Robert Hecht, an American antiquities dealer now on trial in Rome….”