Puerto Rico v. Sanchez Valle: The Obama Administration Abandons Longstanding U.S. Positions on Puerto Rico's Legal Status

I'm wary of the "dual sovereignty" principle as applied to double jeopardy but it has long been the rule and makes some degree of sense. And, applying it to Puerto Rico makes some sense too, but don't know about extending it. Not quite where I want to fight this self-rule battle personally. (Not alone.) Plus, the justice of self-rule is a given but as a matter of constitutional raw power? Not sure how they cannot do the "horrible things" cited here. Finally, the brief (see final pages) suggests the "abrupt change" argument is questionable.