Natural Born Citizenship and the qualifications for which have been established in English Common Law, on which our laws are based, since the 1600’s, two parents born of that nation, the baby being born on that soil.
I believe the author has confused English Common Law with De Vettal.
http://books.google.com/books?id=PNkUAAAAYAAJ&pg=PA17&lpg=PA17&dq=english+common+law+citizenship&source=bl&ots=w5Vd0zi5Ak&sig=TAiGZ_s5_hShp9CV20TAd9wEDLc&hl=en&ei=IHY7S76CDo7csgO937DLBA&sa=X&oi=book_result&ct=result&resnum=6&ved=0CBsQ6AEwBTgU#v=onepage&q=english%20common%20law%20citizenship&f=false
It is interesting to note that Winston Churchill's mother was an American.
I agree, and Ben Franklin was a huge proponent of Vattel, see links: