I remember debates about losing the Panama canal. The big argument was the large super tankers could not fit into the Panama canal so it was not really so valuable any more. Assuming that the nuclear subs will fit into the canal it is hard to imagine it is not a great military value to the Chinese. besides the time it saves it also makes sure no subs can trail their subs. If they can get away with building an serious army base at the Canal it would cut the Americas plum effin in half. Given how nice we have been to the people in Latin America the Chinese might not find such diplomatic bridges so hard to build with the Panamanians.