Just how does this “reversal of his (Obama’s) Presidency happen, under what law? I think you know the answer is that there is no such mechanism and it never will happen. At best his “legacy” may be besmirched, but Trump is already doing a pretty good job of dismantling it piece by piece, which is what really matters in the end.
I know that some are passionate about the NBC issue, but it seems to me that after Obama, the definition has been changed and it is not what some wish to be, and that it will be deemed non-justiciable if a challenge based on the strict interpretation is brought to the Supreme Court.
Minor vs Happersett
In 1875, Chief Justice Morisson Waite wrote the opinion of the court on a unanimous decision, containing the following definition:
...the court observed that “new citizens may be born or they may be created by naturalization” and that the Constitution “does not, in words, say who shall be natural-born citizens.” Under the common law, according to the court, “it was never doubted that all children born in a country of parents who were its citizens became themselves, upon their birth, citizens also. These were natives, or natural-born citizens, as distinguished from aliens or foreigners.