It’s an interesting issue. On it’s face, it seems to me to be quite distinguishable from Obama’s situation. Mitt’s great grandparents were U.S. citizens who went to live in Mexico (polygamous Mormons), so it seems American citizenship is established at least as far as Mitt’s great grandparents. Regardless of what Mexican law says about their status, if the U.S. recognizes them as citizens, and since Romney was born in Detroit, I don’t see an issue. Obama’s father on the other hand was never an American citizen. He was either a British subject and/or a Kenyan national, so there’s no way he could confer ‘natural born citizenship’ to his son, regardless of where Barack was born...which has never been conclusively established.
In said case, Mexican law would supersede American law if it helps achieve an outcome which they want. Got it?
He didn't need to confer anything to his son other than his own flawed genes. Zero was born a citizen and is therefore natural born. That's all it means citizen by birth, as opposed to naturalization.
So give it up unless you like looking like a jackass. You aren't going to prevail with this ridiculous argument and even if you did, Obama's neighbor Billy Ayers would still be eligible, de Vattel be damned!