as far as I jnow he didnt...
But his bigamous grandfather had renounced his US citizenship wshen he fled from the US with his many “wives” and children...
When he left the US it was for good choosing to live a life of sin in Mexico...
He did not intend to return nor live under the jurisdiction of US laws ever again...
The bigamy laws in the US would have caused him to be jailed..
decades later it was only a revolution in Mexico that caused some of the Romney family to enter the US as refugees...
They hid among about a 1,000 returnoing US citizens, none of them asked for ID or papers because of the circumstances...
The border officials just thoughtall of the 1,000 were US citizens just visiting Mexico..
However the Romneys were by then Mexican citizens..
When Mexican born George Romneyy ran for president in 1964 and 1968 there was a problem with his citizenship...
His lack of US citizenship was being discussed at the time..
He was beaten by both Barry Goldwater and Nixon so the inquiry into his eligibility for POTUS was not persued..
Wikipedia states that George Romney’s father did not relinquish his US citizenship. Do you have a source that says that he did so?
If grandma Romney left the US vowing never to return, but did not officially (whatever that means in the context of citizenship) renounce his citizenship, then he would have remained a US citizen. This means that George Romney was a citizen but not natural born, and therefore Mitt Romney, if he was born in the US, was a natural born citizen.
If George’s father renounced his US citizenship in a legally valid way, and George Romney never took on American citizenship, then Mitt Romney would be in exactly the same situation as Barack Obama and, as far as I can see, would be ineligible to be President.
The issue turns on whether George Romney’s father renounced his US citizenship in a way that was legally valid and was not a US citizen when George was born in Mexico.