Constitutional FAQ Answer #121
Q121. "What if the President and Vice President die and the succession goes to a person who is an American citizen but not by birth. Is this possible?"
A. It is possible that this scenario can happen, however unlikely. In this case, the law governing the line of succession also specifies that any person holding an office in the line who is constitutionally unqualified to be President under normal circumstances would be passed over and the next eligible person in the line would become President. For example, if the President and Vice President were both killed and the Speaker of the House was born in Canada, the presidency would pass to the President Pro Tempore of the Senate.