America doesn't acknowledge ROYAL TITLES. Actual American citizens are NOT even permitted to have them; they can only accept honorary ones. And besides which, Winston and his cousin were born in England with fathers who werfe Britsih citizens at the time of their births.
Again, if Cruz is allowed to run- then Churchill and The Duke of Marlborough would be able to run.
As would the Arab Prince who is a direct descendant of The Prophet Mohammad if they can’t find the formal renouncement of citizenship of his mother.