Well I brought up the question of his citizenship status some time ago, specifically being unsure how his grandfather fleeing the US affects his citizenship.
Well now it has come out that his Grandfather bought and owned land in Mexico... this is important because at that time, just as now, only Mexican citizens can own land in Mexico. And at that time one could only become a Mexican citizen if they renounced all other citizenship's; dual citizenship's were not allowed.
So, not only did Grandpa Romney flee the nation as a criminal, he renounced his American citizenship and became a Naturalized Mexican citizen. That means that when Mitts Father was later born in Mexico he was a Mexican citizen.
Despite the fact Mitts Dad came to the US and was Governor of Michigan, he never became a US citizen. Mitt being born in Michigan is a US citizen from birth, thanks to the stupid anchor baby interpretation of law, but since his father was never a US citizen (JUST LIKE OBAMA'S) Mitt is not a Natural Born Citizen.
And now it is looking like they will make Rubio the VP pick and he also isn't Natural Born since neither of his parents were citizens at the time of his birth.