I have posted a new article, with co-conspirator Steve Sachs, and professor Jud Campbell at Stanford, on the original meaning of the Privileges or Immunities Clause of Section One of the Fourteenth Amendment: General Law and the Fourteenth Amendment, forthcoming in the Stanford Law Review.
Our core claim is that the privileges or immunities of citizens were defined by the unwritten general law recognized by Swift v. Tyson and later deprecated by Erie Railroad v. Tompkins.
Here is the abstract: