I think a candidate should have 100% American-soil/born ancestry for three generations in order to be qualified. (American soil would include overseas military bases.)
You mention “divided loyalties”, and that’s huge. The “old country” in their minds and hearts would dilute their patriotism to America.
Of course, that would disqualify all of the top three candidates.
Probably a million things wrong with my idea, but FWIW...
IRREFUTABLE AUTHORITY HAS SPOKEN
(Oct. 18, 2009) The Post & Email has in several articles mentioned that the Supreme Court of the United States has given the definition of what a “natural born citizen” is. Since being a natural born citizen is an objective qualification and requirement of office for the U.S. President (and VP), it is important for all U.S. Citizens to understand what this term means.
http://www.thepostemail.com/2009/10/18/4-supreme-court-cases-define-natural-born-citizen/
BTW, US military bases are not necessarily US soil. It depends on the Status of Forces Agreement with the host country.
I am presently reading a book titled “The Forgotten War America in Korea 1950-1953” by Clay Blair. On page 145, there appears a quotation from a Col Michaelis, newly appointed regimental commander of the 27th Infantry “Wolfhounds” regiment where he says, “We’d just had our first child-a daughter. The only thing I had time to do was rush to the American Consulate with my wife and get our daughter certified so she wouldn’t be a Japanese citizen.”
Absent that certification, Japaneses citizenship laws would have been applicable to these two serving in the armed forces of our nation’s natural born US citizen’s daughter. US bases are leased and NOT US soil as embassy’s are. They are still host country soil and their citizenship laws are in full effect if the SOFA do not modify them.
You would have excluded Ronald Reagan.