Since when did the "Carter Center" get to become an international mediator? I think this is way out of line. There are far too many people (mostly left-wingers or worse) roaming the world doing "diplomacy" these days, ranging from Jimmy to Louis Farrakhan. There's probably no way to stop them from traveling about as private citizens. But I don't quite understand why they seem to have acquired semi-official status, and their doings are never rejected by Washington.
Since the left lost the American elections, they seem to have decided that the way to handle it is to set up a shadow government, complete with its own diplomatic corps. I think this should be nipped in the bud; it gives, at best, conflicting messages.