Heritage at State seems to be having a joke with me and The Hopi Tribe. They were going on about the latest batch of Hopi masks they expect the French to declare an "illegal sale". The French have explained in terms that could not be clearer why the sales concerned are not illegal in terms of French law. I have drawn the parallel between this and the way US dealers and authorities treat the sales of objects taken from foreign source countries within the USA. As has been pointed out a number of times, there are no legal grounds by which this can be done while the US refuses to make such items subject to export licensing - when it would become a cut-and-dried matter.
It does not seem an overly difficult concept to grasp. That is what the 1970 Convention is for. Trouble is the US do not recognize all of the articles, focussing on article 9 as a cop-out and the excuse for entering MOUs with a selection (selection made by them of course) of source countries. This is just a waste of time, if you are going to ratify a convention, ratify it and implement it. If you are not, stop pretending.
Pretence is what we get in the "NationalParkService FAQ on "international repatriation of Native American items" to which they sent a link today in answer to my tweet: go.usa.gov/38F6z
The NPS text confuses the issue by not actually explaining what is involved and including a muddle of other information.