
Michelle R. answered 11/26/19
Experienced, Patient LSAT, Law School, Bar Exam Tutor; Writing/Editing
First, let's agree that 'black letter law' means well-established principle of law that is widely accepted and is free from doubt, reinterpretation or ambiguity. Typically this law has been 'on the books' for many years and is followed by a majority of courts and legal practitioners.
Second, Pennoyer v. Neff, an 1878 Supreme Court, required the Supreme Court to determine whether an Oregon state court can exercise personal jurisdiction over a non-resident (Neff) where Neff was not a resident of Oregon and was not personally served with process within Oregon but did hold property in that state. The Court held that in an in personam case (i.e. it is against the person, not the property), the state court cannot exercise jurisdiction over that person unless that party is personally served with process within the state.
Thus, the black letter law of Pennoyer is that a state court can only exercise personal jurisdiction over a party if that party is served with process while physically present within the state.