While Mitt Romney’s father was born in Mexico, he was born to two American citizens and thus was an American citizen at birth - jus sanguinis. Thus Mitt Romney was born in the US to two American citizens, and thus would presumably qualify as a natural-born citizen.
Just seems odd in a country mostly made up of originalist definition Natural Born Citizens, that the last few Presidential candidates, McCain, obama and possibly Romney, haven't been.
I understand it's just the Constitution, so it's not like it's important or anything, but I can't help but wonder why we can't at least try to follow it after a couple hundred years of swearing oaths to defend it instead of undermining it for political convenience.