Interesting--and disturbing. This is the first I've heard of it. It is almost certainly what Obama and his allies would try to claim if, hypothetically, he were ruled ineligible.
Also of note in that link: "The de facto doctrine springs from the fear of the chaos that would result from multiple and repetitious suits challenging every action taken by every official whose claim to office could be open to question, and seeks to protect the public by insuring the orderly functioning of the government despite technical defects in title to office."
A counter-argument that comes to mind based on this explanation is that the de facto doctrine protects officials whose Is may not all have been dotted and whose Ts may not have been crossed and who otherwise acted in good faith--but not a fraud, which Obama would be, if he were found ineligible. After working so hard to bury his past, he cannot be said to have been ignorant of his lack of qualification.
It would get ugly, that's for sure.
The de facto doctrine doesn’t apply if someone knowingly commits fraud to criminally assume a position he is not eligible for. 0thugga has lied and covered up with assistants all his records. He has knowingly committed crimes to hide his ineligibility.
I am not smart enough to know this myself but have read enough of the eligibility threads to know it. El Gato and Red Steel and others know the details. Maybe one will chime in if they’re around.
The doctrine which gives validity to acts of officers de facto, whatever defects there may be in the legality of their appointment or election, is founded upon considerations of policy and necessity, for the protection of the public and individuals whose interests may be affected thereby. Offices are created for the benefit of the public, and private parties are not permitted to inquire into the title of persons clothed with the evidence of such offices, and in apparent possession of their powers and functions. For the good order and peace of society, their authority is to be respected and obeyed until, in some regular mode prescribed by law, their title is investigated and determined.