Chester A. Arthur's father was born in the UK and was still a British citizen at the time of his birth. He was the first president who didn't fit your definition.
...it wasn't enforced against Obama, for very obvious reasons.
What obvious reasons. Because he was black? Isn't every other law enforced on blacks? Out of the millions of people who should've known better, nobody even mentioned that there might be a problem...because he was black?
Fact is, nobody even broached the so-called two American parent requirement on Free Republic until December 8, 2008 -- over a month after Obama's election.
And, of course, no legal objection to Cruz's candidacy was eve upheld.
I find that very hard to believe.