I believe Romney is eligible.
Here is why.
George Romney, though being born a dual citizen was still an American because of his parents. George Romney’s son would have been born to an American father and mother. This makes Mitt a Natural Born Citizen.
Take a look of Obama, he was born British because of his father. Obama Jr. daughters were born in the US to two parents who were Americans (assuming OholyO was born in Hawaii) BUT... because of British law, his daughters could APPLY for British Citizenship and get it due to their grandfather’s full British heritage, and that of their own father. But here is the trigger, the crux.. they would have to apply for it, it isn’t automatic like their father’s citizenship - That of OholyO.
This describes Mitt Romney, Mexican Citizenship wasn’t passed on to him automatically, he would have to apply for it. Just like I would have to apply for Mexican Citizenship, but he would have a stronger case of getting it because his father was born in Mexico.
Citizenship issues get real mixed up real fast, and this is why the term “Natural Born Citizenship” was noted diplomatically. There had to be a baseline to start from.
Danae, for the umteenth time, George Romney was never a Mexican citizen. Mexico never claimed him as one of their own.