That isn’t true of Mexico.
To be a Mexican citizen, one or both parents must be Mexican citizens. Just being born in Mexico doesn’t matter.
Gov.George Romney was born in Mexico to U.S. citizen parents. Mexico did not recognize George Romney as being Mexican, and when his parents returned to Utah when George was 7-years old, he was a U.S. citizen because his parents were Americans.
George Romney couldn’t serve as President, due to his birth in a foreign nation, and dropped his attempt to become a Republican candidate for that office in the 1960s. His son, Gov.Mitt Romney, delivered his ‘Natural born Citizen’ bona fides to the Republican Party early in 2012, as did Ron Paul and Newt Gingrich. Richard J. Santorum, who is ineligible to be President, did not. His father was an Italian citizen who naturalized as a U.S. citizen three years AFTER his son’s birth in Pennsylvania.
Many thanks for the info on Mexico with respect to Romney.
That is an example of the foreign country not having a claim on the person born there.
Then is he a citizen by u.s. rules (most likely).
Since Mexico hasn’t a claim on him, and the u.s does, then he can’t be in the position to have to choose between the two.