Legally it is a little trickier. The constitution requires a president being a "natural born citizen". But that term has NOT been properly defined.
In Obamas´s case, it was never an issue, as his birth certificate states he was born in Honolulu (that's why the birthers concentrated on claiming it was forged). Having been born within the limits of the country, he is a natural born citizen by long established precedent and assumption, no matter who his parents were.
The issue with Cruz is that he was born in Canada, and outside of any US controlled territory. He gets citizenship because his mother was a US citizen at the time of his birth, not because of territoriality. Now, most everyone would agree that having the right of citizenship at birth satisfies the "natural born" requirement, but there is no precedent establishing that, and that is the angle he is being attacked on. Like it or not, he running and/or winning the presidency would create such a precedent, and there could be valid legal challenges along the way. In his place I would arrange for an ally to sue him on this matter in an amicable court and have the matter elevated as fast as possible to get it out of the way.
In Obamas´s case, it was never an issue, as his birth certificate states he was born in Honolulu (that's why the birthers concentrated on claiming it was forged). Having been born within the limits of the country, he is a natural born citizen by long established precedent and assumption, no matter who his parents were.
The issue with Cruz is that he was born in Canada, and outside of any US controlled territory. He gets citizenship because his mother was a US citizen at the time of his birth, not because of territoriality. Now, most everyone would agree that having the right of citizenship at birth satisfies the "natural born" requirement, but there is no precedent establishing that, and that is the angle he is being attacked on. Like it or not, he running and/or winning the presidency would create such a precedent, and there could be valid legal challenges along the way. In his place I would arrange for an ally to sue him on this matter in an amicable court and have the matter elevated as fast as possible to get it out of the way.